In the present work, an analytical equation describing the plate torsion test taking into account the transverse shear stiffness in sandwich plates is derived and numerically validated. Transverse shear becomes an important component if the analyzed plate or shell is thick with respect to the in-plane dimensions and/or its core has significantly lower stiffness than the outer faces. The popular example of such a sandwich plate is a corrugated cardboard, widely used in the packaging industry. The flat layers of a corrugated board are usually made of thicker (stronger) material than that used for the corrugated layer, the role of which is rather to keep the outer layers at a certain distance, to ensure high bending stiffness of the plate. However, the soft core of such a plate usually has a low transverse shear stiffness, which is often not considered in the plate analysis. Such simplification may lead to significant calculation errors. The paper presents the generalization of the Reissner’s analytical formula, which describes the torsional stiffness of the plate sample including two transverse shear stiffnesses. The paper also presents the implementation of the numerical model of the plate torsion test including the transverse shear stiffnesses. Both approaches are compared with each other on a wide range of material parameters and different aspect ratios of the specimen. It has been proved that both analytical and numerical formulations lead to an identical result. Finally, the performance of presented formulations is compared with other numerical models using commercial implementation of various Reissner–Mindlin shell elements and other analytical formulas from the literature. The comparison shows good agreement of presented theory and numerical implementation with other existing approaches. Composite materials play an important role in many practical engineering designs. They consist of at least two materials, which are called fiber and matrix material, or are composed of more than one layer. A special class of composite layered materials is sandwich plates; they consist of a soft core and two outer sheets. The internal one supports the faces and provides the overall flexural stiffness of a structure. In composite laminates or sandwich plates and shells, an important role is played by flexural and torsional stiffness. A typical example of such a sandwich plate is the 3-layer corrugated cardboard, in which the core is corrugated and therefore light. The role of the core called “flute” in jargon is to provide shear stiffness while the outer sheets called “liners” ensure the flexural stiffness. Transversal shear effect is especially important in thick plates.Avilés and coauthors conducted experiments on the torsion of sandwich panels and made measurements of the shear properties . The autOver the years, there have been many approaches in the literature for calculations or experimental determination of the transverse stiffness of sandwich and corrugated plates. In 1978, Cohen published a paper on the transverse shear stiffness of laminated anisotropic shells . NordstrAnalytical or numerical analysis of the composites with heterogeneous layers is not trivial. A crucial point in the analysis of such plates, e.g., corrugated cardboards, is a method of simplification of the heterogeneous layer. This process is called a homogenization, a method for obtaining the effective properties of the corrugated core ,11. AfteIn analytical or numerical analysis of corrugated sandwich panels three approaches are distinguished in the literature: classical laminated plate theory (CLPT), first order shear deformation theory (FOSDT) and higher-order shear deformation theory (HOSDT). Notice that the CLPT do not include the transverse shear effect. The FOSDT has been proposed by Reissner and Mindlin ,18. CarlIn this paper, a new generalized form of the Reissner analytical formula describing the torsion of the sandwich plate is proposed. The torsional stiffness and both transverse shear stiffness are taken into account in these considerations. The presented formula is compared with the numerical models and other analytical approaches existing in the literature.z-axis. It was assumed that cross sections remain straight during deformation, but they do not necessarily remain normal to the middle surface. The assumption is typical for shear deformable plates.A plate of constant thickness The equilibrium equations are expressed in terms of the bending moments y direction, In the present study,  adopted ,18.The relation between bending moments and the curvatures can be expressed as:The foregoing constitutive equations incorporate a limiting-type orthotropy assumption due to sample size considered a≫b, see a, which leads to ,26:(11)TSubstituting the torque with a pair of forces, see Determining the transversal shear stiffness of the sample from a static torsion plate test has been recently studied by the authors . The stuhe paper , constanFurther research showed that despite the fact that AKK  has goodAssuming the In both the Relationships between strains  analysis has been a popular method for modeling advanced engineering problems. Due to its popularity and universality, the developers of FE software more and more often provide their users new functions, extending its capabilities. Following this trend, the software often allows one to include users’ material or element subroutines tailored for particular needs. Therefore, the FEM approach in comparison to the analytical approach is easier to be applied in the modern engineering tools. In the laminated plate element, the field variables, The membrane, bending and shear strains associated to the displacement in Equation (40) can be therefore obtained as follows:Substituting Equations (40) and (42)–(44) into Equation (39) leads to:It is noted that the shear locking phenomenon can appear in Equations (50) and (51) as the plate thickness decreased. To overcome this adverse the Reissner–Mindlin plate quadrilateral element with assumed transverse shear strain fields was adopted here. We used the plate element with 4 nodes with linear shear field, which initially was developed by Bathe and Dvorkin ,28. Its A standard 4-noded Q4 element ,34 is chThe The relationship between the Cartesian transverse shear strains at the middle-edge points and the natural transverse shear strains is:The Cartesian transverse shear strains at the four sampling points are then related to the nodal displacements by:The substitute transverse shear strain matrix was obtained byHere, the element is described as QLLL . The element satisfies conditions ,36,37, with commonly used finite elements were essentially worse. In the worst cases, the overestimation of the force was even up to four times. In this comparison, the 3-node triangular element performance was surprisingly moderately good. Moreover, the differences between rectangular and square samples were significant. It should be noted that in rectangular samples, if the material had a large transversal shear stiffness along a longer dimension of the sample, the differences of all methods to the reference solution were very low.


A very flexible structure with a tunable stiffness controlled by an external magnetic stimulus is presented. The proposed structure is fabricated using two magnetic-responsive materials, namely a magnetorheological elastomer (MRE) as a skin layer and a magnetorheological fluid (MRF) as a core to fill the void channels of the skin layer. After briefly describing the field-dependent material characteristics of the MRE and MRF, the fabrication procedures of the structure are provided in detail. The MRE skin layer is produced using a precise mold with rectangular void channels to hold the MRF. Two samples are produced, namely with and without MRF, to evaluate the stiffness change attributed to the MRF. A magnetic field is generated using two permanent magnets attached to a specialized jig in a universal tensile machine. The force-displacement relationship of the two samples are measured as a function of magnetic flux density. Stiffness change is analyzed at two different regions, namely a small and large deformation region. The sample with MRF exhibits much higher stiffness increases in the small deformation region than the sample without MRF. Furthermore, the stiffness of the sample with MRF also increases in the large deformation region, while the stiffness of the sample without MRF remains constant. The inherent and advantageous characteristics of the proposed structure are demonstrated through two conceptual applications, namely a haptic rollable keyboard and a smart braille watch. Smart fluids, including electrorheological fluids (ERFs) and magnetorheological fluids (MRFs), can be effectively applied in a number of scenarios, including as an automotive damper and for vibration control in flexible structures. ERF consists of a carrier liquid with fine nonconducting particles, and its apparent viscosity depends heavily on an electric field applied to the fluid domain. Thus, ERF is often utilized as a core layer in sandwich structures  to improve damping properties or to modify the modal characteristics of a structure ,2,3. HowSome applications, for example bio-health patches and wearable haptic gloves, require a soft outer skin layer. A magnetorheological elastomer (MRE) is a skin  comprising of rubber embedded in magnetic-responsive iron particles. The rubber component contributes sufficient softness to allow for the manufacturing of a wide range of shapes and curvatures. Previous studies have demonstrated the effectiveness of MRE-based structures ,8. UnlikThe main technical contribution of this work is to fabricate a new soft structure whose stiffness can be tuned by external magnetic field. The field-dependent stiffness of the structure was evaluated experimentally. The structure consisted of two magnetic-responsive materials, namely MRE as a skin layer and MRF as a core to fill void channels in the skin layer. The MRE skin layer contained 30 wt.% of carbonyl iron particles (CIP) and was produced via a multiple step process, including molding and curing. The mold was made from machine structure carbon steel (S55C) and had excellent wear resistance. The mold had rectangular void channels into which MRF was injected, followed by bonding between the upper and lower skin layers. Two samples with identical geometry and dimensions were produced with and without injecting MRF into the channels. Magnetic analysis with permanent magnets was conducted to ensure that the magnetic field was well-distributed. The samples were fixed to a specialized jig in a universal tensile machine and the tensile force was detected by the load cell at the top, while the tensile length was determined using an embedded encoder attached to the motor. After several trial tests considering data collection, noise and breaking possibility of the samples, the tensile speed was fixed at 500 mm/min. The force-displacement curves of two samples were used to establish the stiffness change as a function of the magnetic flux density. The sample without MRF exhibited an increase in stiffness of 72.8% in a small deformation region when a 0.3 T magnetic field was applied, while the sample filled with MRF exhibited a 156.6% increase under the same conditions. The stiffness of the sample with MRF increased across a large deformation region, while the stiffness of the sample without MRF did not vary with the application of a magnetic field. Unlike the conventional smart structures shown in An MRE is a composite material that reacts to a magnetic field. It has an elastic solid state in the absence of the magnetic field, as opposed to MRF which is fluid. However, MRE has been used in similar application fields to MRF, including the use as a vibration isolator. The magnetically sensitive particles in MRE were bound within a silicone rubber matrix and an additive as shown in MRF is a typical controllable intelligent fluid and is usually composed of a silicon oil-based fluid and ferrous particles that interact with a magnetic field. If an MRF is acted upon by the magnetic field, its yield stress can quickly change as the particles align to form chain-like structures. The main particles in MRFs are micro-sized. An MRF is generally treated as Bingham fluid, which is a type of non-Newtonian fluid ,19. CommTwo samples were produced to demonstrate the effects of the MRF on the stiffness change in the soft structure. The configurations and geometric dimensions of the samples are given in The production process was divided into four parts as shown in The change in stiffness of the soft structure as a function of the magnetic field intensity was investigated using the experimental apparatus and set-up shown in refer to e.The stiffness of the magnetic-responsive soft structures was compared to the mechanical properties of MRE structures in previous studies. The stiffness was defined as the slope of the force-displacement curve, but elastomers generally do not exhibit linear elastic deformation. Borin et al.  performeThe sample with MRF behaved completely differently as shown in d, db and n denote the distance, bifurcation within large and small deformation and the order of polynomial expression, respectively. F(d) was fitted to order 3 and 1 for the samples with and without MRF, respectively. The order of the samples was chosen based on the tensile force-displacement curves given in Unlike the small deformation region, stiffness did not increase linearly with displacement in the large deformation region and was instead characterized by an instantaneous slope based on the relationship between the tensile force and the displacement. Due to its nonlinearity, the tensile force-displacement curve was represented by a polynomial curve fitted as follows:The new soft structure produced using two magnetic-responsive materials, namely MRE and MRF, with a stiffness tuned by external stimuli has been validated experimentally. Two conceptual applications utilizing the proposed soft structure were presented in this section in order to attract further interest in the present work for a wide range of applications. The first conceptual application is a rollable keyboard with a haptic function. There are two major issues associated with current keyboards, namely hardboards, which prevent portability, and the constant pressure of each key, which causes typos due to the lack of distinguishable pressure on each key. Both problems can be resolved by using the keyboard shown in The second conceptual example shown in A new soft structure with a stiffness tuned by external magnetic stimuli was produced, and the stiffness tuning capability of the structure was experimentally validated. The soft structure used two magnetic-responsive materials, namely an MRE as a skin layer and an MRF as a core. The MRE skin layer contained 30 wt.% carbonyl iron particles (CIP) and was manufactured through a multi-step process, including molding and curing. The rectangular mold with void channels to hold MRF was made from machine structure carbon steel (S55C). After bonding the upper and lower skin layers, two samples were produced, namely one with MRF-filled channels and one without (empty channels). Finite element analysis was conducted to investigate the magnetic field distribution with permanent magnets and the samples were fixed to the specialized jig in a universal tensile machine. The force-displacement curves of the samples with and without MRF were measured at a fixed tensile speed of 500 mm/min. The stiffness of the sample without MRF increased by 72.8% in the small deformation region when a 0.3 T magnetic field was applied, while the stiffness of the sample with MRF increased by 156.6%. The stiffness change in the large deformation region was also evaluated through curve fitting. The stiffness of the sample without MRF did not change in a magnetic field, while the stiffness of the sample with MRF increased by 330.9% in a 0.3 T magnetic field. The soft structure exhibited a stiffness change across a wide deformation range. The soft structure was proposed for use in two conceptual applications, namely a rollable portable keyboard and a smart wearable braille watch. These applications clearly demonstrate the great potential of this soft structure and should attract more interest in further applications of various fields including bioengineering.However, in order to realize commercial products utilizing the proposed soft structures, several works need to be explored in depth. Firstly, analytical equation of motion and the finite element analysis of the proposed soft structure should be carried out to optimally fabricate any shape of the soft structure. It is remarked here that the finite element analysis of composite tubes characterized by different Young moduli has been investigated in . Secondl


Cable-based actuation systems are preferred in rehabilitation robotics due to their adequate force transmission and the possibility of safely locating the motors away from the patient. In such applications, the cable dynamics represents the prescribing component for the system operating loads and control. A good understanding of the actuation, based on cable-conduit transmission, is therefore becoming mandatory. There are several types of cable-conduit configurations used for the actuation. Currently, there is lack of information in literature with regard to the push-pull cable type. Therefore, the main focus of this contribution is to evaluate push-pull cable-based actuation used within wearable robotic devices. This study includes working principle description of push-pull cable actuation with its characteristic advantages and drawbacks. The use of push-pull cables in bidirectional force transfer with remote actuation is investigated being integrated in a test-stand setup of a novel gait rehabilitation device. The experimental results and close analysis of the push-pull cable-based actuation system outline its performance, the overall dynamic behavior and the transmission efficiency of push-pull cables used for powered orthoses. In the development of novel rehabilitation robotic devices engineers are faced with the challenge of combining suitable design concepts, high performance actuator technologies and dedicated control strategies in view of improved physical human-robot interaction (HRI). According to a number of investigations on different actuation approaches for exoskeletons, the low power/weight and force/angle ratios are still major drawbacks Herr, . ClassicCable driven actuation, such as: open-ended cables Tsai, , endlessIn recent years, cable-conduit actuation gained significant attention in rehabilitation robotics FinFThe total wrap angle (θ) of the cable system is represented in Figure There is only limited literature on experimental evaluation of friction between the cable and outer conduit for push-pull cables. The experimental results on PPC static friction evaluation were presented in Slavnić et al. , with thIn the initial testing phase and the evaluation process of PPC-based actuation system, a test-stand setup of the CORBYS gait rehabilitation device .The operating range of the slider-crank mechanism is a function of the lengths of the crank, connecting the rod and the distance of the slider line from the crank pivot, therefore:Fm is equal to:Fs that acts on the push-pull cable end is represented by:Fma – the axial force transmitted by the connected rod is expressed as:The force Fin vs. Fout). Based on these force measurements, Equations  were used to calculate the torque required for the orthosis joints actuation.Several experiments were performed in order to evaluate the transmission efficiency of the PPCs by comparing forces measured on the motor and respectively, the orthosis joint sides of the cable .The force measurements are provided by the two force sensors (U9C), located on the joint (indicated in graphs by JF) and the motor sides (indicated in graphs by MF) of each PPC. This data was used later to determine the torque parameter τThe hip and knee joints were tested in separate trials. Therefore, two sets of experiments can be distinguished, for the hip and respectively, for the knee. Each set consisting of two tests with different motor velocities following a sinewave amplitude.Hz and then to 0.05Hz.For the hip joint actuation experiments motor amplitude was set to ±25°. To vary the velocity, sinewave frequency was set to 0.15Hz and then 0.05Hz.For the knee joint experiments the motor amplitude was set to 30°, starting from the initial position when the orthosis leg is in vertical position. In contrast to the hip actuation experiments, hier PPC was always in tension due to the fact that the orhosis knee joint has limited range of motion and does not allow extension. Therefore, the dynamics of PPC in contraction was not characteristic for the knee actuation experiments. However, the same frequencies as the ones used in the hip experiments were used, 0.15Force and position measurements were collected from all the experiments and exported to MATLAB. Each experiment was performed in several trials. Out of continuous data stream an arbitrary period of 30 s was selected for further data processing. The same period was considered for all four experiments.In Figures Figure It can be also observed that the angle of the joint exceeds that of the motor by 2–5°. This appears due to the various geometrical dimensions of the slider-crank elements used on the joint and respectively, the motor sides, as specified in Table In the second set of experiments, see Figures Figure Fin, obtained from the hip and knee actuation sets of experiments. According to the graphs we can observe almost linear relation between motor torques and forces.In Figures Fin and Fout ) measured in the experiments. According to this data we can conclude that the difference between the efficiencies values is not considerable for the two selected speeds. Also, it can be observed that in pushing phase the efficiency is slightly higher as less force is required to perform the movement. Therefore, the efficiency depends on the operating loads, which is in line with the specifications from literature, presented in the introduction part of this article. It can be also observed that in contrast to the hip PPC, the knee PPC is operating with less efficiency. This can be explained by the different geometry and of the knee cable, which is longer and thinner with an increased bending curvature.In Table In this paper were addressed the critical points of cable-driven transmissions, including their dynamic behavior, main advantages, and drawbacks with the focus on the push-pull cable configuration. PPC-based transmission has been implemented in actuation of a new gait rehabilitation robot CORBYS, but in order to test the performance of actuation system its simplified version (a test-stand) has been used for the experiments. One of the main goals of experiments was to estimate the transmission efficiency of the PPC and to observe the overall dynamic behavior of the system. The obtained results suggest to think about following control optimization strategies for compensation of friction, nonlinearities, and backlash issues.All types of cable-conduit transmissions present drawbacks, such as nonlinear friction highly dependent on curvature and geometry of the cable. The dynamic behavior and functional characteristics of Bowden and PPC transmissions are very similar, but there are also few differences. In comparison to PPC, Bowden cable-based actuation systems can operate only in pulling direction. Taking into account that PPCs are larger in diameter and more stiff, they are able to transmit larger forces compared to the Bowden cables. Moreover, PPCs have the ability to transfer forces in two directions, pushing and pulling.Considering hip joint experiments, if we compare force readings provided by the motor side force cell  and joint force cell , it can be observed that the higher force is needed at the motor side. This outcome appears due to the energy losses caused by nonlinear friction along PPC actuation mechanism.When the motor achieves the maximum imposed angle position (−25° or 25°) it changes the actuation direction. Starting from that moment, according to the graphs, it can be observed that the gravity helps the movement and JF and MF are overlapping. According to the experimental results illustrated in Figures In contrast to the hip actuation experiments, the push-pull cable in knee joint experiments was always in tension because the orthosis leg was not passing through the equilibrium position. Therefore, observing the PPC dynamics while in contraction (which is pushing phase) is missing for the knee actuation experiments. The difference in force readings between the motor sensor (MF) and joint sensor (JF) can be visualized on the graphs. This difference is produced by losses of energy due to the dynamics of the actuation system and push-pull cable nonlinear friction. This force difference is more evident in contrast to the hip PPC, due to the physical characteristics of the PPC used for the kne actuation joint. Namely, it is longer, thinner (see Table m was determined based on sensors force measurements (MF) and using formulas 4, 7–9 presented in theoretical part of section 2.Taking into account that the exact model of the PRL+ actuator is difficult to obtain due to its nonlinear characteristics, the motor torque τm was one of the goals followed in this contribution. This torque will be used as a reference for further investigations on torque control strategies as an alternative to the position control used so far. Torque control is especially important for the applications where human-robot interaction is involved, such as in exoskeleton applications. This solution permits to avoid integration of the expensive torque sensors in the system and reduces its mechanical design complexity.The establishing of the motor torque τCable-based actuation systems show many advantages over classical actuators when implemented in various robotics related applications. The employment of this type of actuation in wearable devices permits the dislocation of the actuators from the orthosis so that inertia of the motors is not imposed on human body, therefore, improving safety and functional aspects. Still, issues related to control challenges, specific mechanical design requirements and assumptions have to be considered. These aspects were addressed in this paper together with the evaluation of cable-based force transmission system for powered orthoses.Several experiments were performed to evaluate the transmission efficiency of the PPCs by comparing forces measured on the motor and respectively, the orthosis joint sides of the cable. Based on these force measurements, the torque required for the orthosis joints actuation was computed.Additionally, we noticed that the efficiency of the PPC force transmission is highly dependent on the configuration of the actuation components of the system, such as mechanical design, geometry of the PPC, bending angles, and cable preloads.The other objective during the experiments, was to observe the effect of velocity changes on operational and output forces. According to obtained results the force amplitude does not change considerably but the force oscillations are more evident at higher velocities.According to the obtained results, can be concluded that all specific features and compromises typical for cable-conduit-based transmissions are also characteristic to PPC actuation. Still, using PPC actuation in certain applications could be preferred due to the number of individual advantages. For example, capability to transfer larger forces in two directions and less complex mechanical construction of the actuation system. The use of PPC actuation systems is advised in applications where the light-weight design and transmission of large forces are required, definitely a solution to consider in wearable devices.SG, CR-G, and VG were working together on experimental setup and post-processing of results. BV and DL were providing guidance in this research study, as well they contributed in a writing process of this article.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Penetration of a flexible and steerable needle into a soft target material is a complex problem to be modelled, involving several mechanical challenges. In the present paper, an adaptive finite element algorithm is developed to simulate the penetration of a steerable needle in brain-like gelatine material, where the penetration path is not predetermined. The geometry of the needle tip induces asymmetric tractions along the tool–substrate frictional interfaces, generating a bending action on the needle in addition to combined normal and shear loading in the region where fracture takes place during penetration. The fracture process is described by a cohesive zone model, and the direction of crack propagation is determined by the distribution of strain energy density in the tissue surrounding the tip. Simulation results of deep needle penetration for a programmable bevel-tip needle design, where steering can be controlled by changing the offset between interlocked needle segments, are mainly discussed in terms of penetration force versus displacement along with a detailed description of the needle tip trajectories. It is shown that such results are strongly dependent on the relative stiffness of needle and tissue and on the tip offset. The simulated relationship between programmable bevel offset and needle curvature is found to be approximately linear, confirming empirical results derived experimentally in a previous work. The proposed model enables a detailed analysis of the tool–tissue interactions during needle penetration, providing a reliable means to optimise the design of surgical catheters and aid pre-operative planning.The online version of this article (10.1007/s10237-020-01310-x) contains supplementary material, which is available to authorised users. PBNs possess a structure with a number of interlocked segments that slide relative to one another, with motion inspired by the egg-laying channel of certain wasps. PBNs are capable of 3D steering, thanks to a bevel tip and a programmable offset between the segments . The stage ends once the strain energy accumulates to a critical value, at which a crack is initiated.Cut propagation until full penetration:Once a crack is initiated, the external work is also consumed by frictional dissipation and work of fracture. Following initial rupture, there is a relaxation of the elastic strain energy (region 2a) and beginning of the cut propagation under increasing force (region 2b).Sliding after full penetration:When the indenter has penetrated the material for the whole depth and breaks through the other end, there is another stage of relaxation, and the frictional resistance is the only remaining contribution (region 3).The mechanics of needle penetration is about the complex interaction between needle and target tissue. The detailed insertion behaviour depends on a great number of variables, e.g. the characteristics of the indenter, the properties of the target material and the penetration rate  designed at Imperial College, London  has the capability to account for the nonlinear behaviour of soft materials and allows the inclusion of the contact constraints imposed by the penetration of the needle. In two-dimensional implementations of CZM, the fracture process zone is lumped into a line ahead of the crack tip, and the crack surfaces interaction is defined through a stress–displacement relationship describing the damaging mechanisms taking place close to the crack tip. The length of the cohesive process zone ace Fig. a:3\documDepending on the shape of the stress–displacement relationship, different types of failure can be described: for quasi-brittle materials, a possible choice is given by the bilinear curve  the FE analysis and (ii) a post-processing step. The complete formulation is summarised in Fig. Part (i) is carried out with the commercial software SIMULIA Abaqus 2017 (Dassault Systèmes), using the implicit static solver and accounting for nonlinear geometry. Each iteration describes the penetration of the needle from the initial configuration . The needle is prevented from buckling by moving between two rigid vertical surfaces, which are frictionless, fixed and represent delivery through a trocar, which is common for flexible catheters. Contact constraints are enforced using a Lagrange multipliers method, with a frictional interaction between the needle and the substrate described by the Coulomb frictional law. Since the material of the substrate is highly deformable, it was necessary to introduce an initial notch to ease the convergence at the stage of indentation, as shown in Fig. The refined inner region of the substrate is remeshed at each iteration of the penetration algorithm, in order to accommodate the advancement of the needle. The remeshing stage is carried out in MATLAB, using the mesh generator DistMesh , measured at a specified distance At this point, a criterion to determine the crack propagation direction needs to be defined. Several alternatives have been proposed in the literature Supplementary material 2 (mp4 24585 KB)Below is the link to the electronic supplementary material.


The issue of information security is closely related to every aspect of daily life. For pursuing a higher level of security, much effort has been continuously invested in the development of information security technologies based on encryption and storage. Current approaches using single-dimension information can be easily cracked and imitated due to the lack of sufficient security. Multidimensional information encryption and storage are an effective way to increase the security level and can protect it from counterfeiting and illegal decryption. Since light has rich dimensions  and synergy between different dimensions, light as the input is one of the promising candidates for improving the level of information security. In this review, based on six different dimensional features of the input light, we mainly summarize the implementation methods of multidimensional information encryption and storage including material preparation and response mechanisms. In addition, the challenges and future prospects of these information security systems are discussed. Information security has become a significant global issue not only in economic and military fields but also in the daily lives. Because of the large temptation of enormous profits which can be potentially obtained from the acquisition of secured information, the methods for counterfeiting or illegal decryption emerge endlessly –3. ThereA system of information encryption and storage can be simplified as the integration of the input, the material, and the output . The sysLight, as the most common physical quantity in daily life, is one of the promising candidates as the input owing to its easy accessibility and high-level controllability , 39. TheIn this review, we will focus on light itself as the sole input, to summarize how it plays the role in the multidimensional information encryption and storage. As shown in Conceptually, light includes not only visible light within the range of 400 nm to 700 nm that can be perceived by human eyes but also nonvisible light like ultraviolet (UV) light and near-infrared (NIR) light. Light of different wavelengths as the input means discrepant energy inputs. Based on the rule of energy matching, they could induce different physical or chemical changes of materials, which further exhibit the encrypted and stored multidimensional information. For information encryption and storage, whatever the input is, the most convenient output is in the form of visible light that could be easily read out by the naked eye, smartphone, or miniature spectrometer . Hence, DCL means the optical process that produces longer-wavelength emission when exposed under shorter-wavelength excitation, with a change from the high-energy photon to the low-energy one. In general, DCL materials are excited by UV light or short-wavelength visible light like violet or blue light. Most luminescent materials including organic luminescent dyes, aggregation-induced emission (AIE) molecules, and semiconductor quantum dots are all regarded as the typical DCL materials –57. BaseAlternatively, another simpler approach for multidimensional information encryption and storage is to assemble multiple DCL materials with different excitation and emission properties. A coordination compound of europium(III) and fluorescein was selected to form a dual luminescent ink for printing on the substrates . Under Uvis conversion). For UCL materials, different Ln3+ ions doped into one host material can play the role as sensitizers to harvest photons from the input light or activators to emit different-wavelength light, respectively. Owing to the specificity of UCL from the low-energy photon to the high-energy one, it shows the great advantage of avoiding background fluorescent interference. Thus, there are more choices of substrates to provide the high-quality information output under different conditions . Th. Th4:Yb/4@NaYF4) were fabricated, where the optimal concentration of Er3+ could increase to 100 mol% . Th. Th2)  in intensity , 73. TheIrreversible reactions related to light are usually based on either the photoinduced decomposition by cleaving functional groups or the photoinduced addition/polymerization to form stable covalent bonds. Different irradiation durations indicate the differences in the extent of reaction.Taking the photoinduced decomposition as an example, it is of great importance to control the rate of decomposition precisely in order to keep just a piece of information for an irradiation time. The controllable photoresponsive transition of 9,9′-bis(anthracene) sulfoxide (AnSO) made it a promising candidate for multidimensional information encryption and storage . After ecis-trans isomerism or the tautomerism . Ow. Ow92]. y-axis of array. After switching the direction of polarization light along the x-axis of array, the microimage of the university's main building appeared , it generated a holographic image of a smiley or sad face at the third harmonic frequency in blue (at 422 nm), respectively  94]..94].The polarized plane of CPL is dynamically changing, which can be classified as left-handed circular polarized light (L-CPL) and right-handed circular polarized light (R-CPL) according to the phase difference. Similar to LPL-responsive materials because CPL can be decomposed as the combination of two LPL, it is feasible to design specific nanostructures to display different optical responses to L-CPL and R-CPL. One example of these nanostructures was the double-layer aluminum arcs embedded in a transparent polymer film as chiral color pixels  95]. By. By95]. Owing to the special chirality of CPL, chiral molecules are one of the promising candidates to show different responses to L-CPL and R-CPL . Celluloz-direction was engineered by stratification of an uncrosslinked liquid crystal elastomer and a chiral liquid crystal network under the linear polarized UV light . By. By4:Yb,Besides, it could also be achieved by the integration of multiple materials with different light-power sensitivities. When photonic crystal dots containing rhodamine 6G were controllably shaped as bumps, plates, and coffee rings on the substrate, they showed different fluorescence enhancement abilities . After pAlthough it is maneuverable to adjust the power of light, there still exist challenges such as severe local heating when using high-power light. The instability of luminescent materials under high-power light irradiation will affect the successful information readout, which limits its application to some extent.In conclusion, multidimensional information encryption and storage when the input is light have been proven as an effective and reliable approach to increase the security level of information. Six-dimensional features of the input light  could be used separately or synergistically to encrypt and store multidimensional information in one material. It is simple and practical to modulate light to meet the requirements of different inputs. The pros and cons of these six-dimensional features are summarized in Though decent progress has been achieved, it is still essential for us to think deeply about the current challenges. First, it is still not achievable to take full advantage of multidimensional characteristics of light for safer information encryption and storage. On the basis of information encrypted and stored in one-dimensional feature of light, other dimensional features of the input light can be synergistically introduced to realize the multidimensional information system. Thus, the crosstalk problem among different information should be placed much emphasis, which requires great resolving ability to distinguish the small enough discrepancy to decrypt as different information. In other words, the preparation of materials or the design of nanostructures with multiple functions should be more precise and more controllable. Second, the stability of information storage or readout is rather important, which has a direct impact on the quality of information output. The irreversible photobleaching phenomenon may appear when luminescent materials are exposed under UV light with high power for a long time. It should have the capacity not only to keep for a long time under the ambient condition but also to obtain stable information readout under the special input conditions. Third, the available and portable way for information readout is the key factor for expanding its application in daily life, even though it may be a sophisticated structure or the extremely special material. It is important to keep high-level information security and good practicability simultaneously. Other technologies for simplifying or miniaturizing the device for the input or the output will continuously drive this field to make tremendous progress. Last but not least, different from the research on the lab, the economic cost is more worthy of consideration for every manufacturer in practical application. Because the eventual goal of information security is to gain more benefits, there will be a comparison between the cost of different information security technologies and the profits of information itself. Cost-efficient preparation methods of novel materials suitable for multidimensional information encryption and storage are strongly required.Therefore, more efforts on the multidimensional information encryption and storage with light as the input are needed. To summarize, future innovative works should continue to aim at the acquisition of high-level information security through three aspects: the input, the material, and the output. For the input side, as mentioned in Introduction, light is not the sole choice. Other forms of physical signals such as force, heat, electricity, magnetism, or chemical signals could be used together as the multiplexed input. A variety of inputs indicate more channels for different kinds of information encryption and storage to provide high-level information security. Then, the selected input is closely related to the material. Researches about novel functional/smart material will provide greater possibility to find the optimal one to meet the requirement of the input. By introducing fabrication methods with high spatial resolution, it is possible to make the size (shape) of the smallest information unit further downsize (refine). It is an important basis to realize high-density information storage and assure information readout with high quality. For the output side, information readout should be more efficient and more completed. For example, it can be considered not only as colored pattern information but also as the information of spectral pattern that contains more channels for information encryption and storage. Therefore, the rapid development of integrated process technologies, preparation of multifunctional materials, and information sensing technology will dramatically promote the capacity to control the input, the interaction between the input and materials, and the output. With the ingenious encryption to store multidimensional information in one material, these methods for information encryption and storage will play an important role in the future of information security.


Material extrusion additive manufacturing (ME-AM) techniques have been recently introduced for core–shell polymer manufacturing. Using ME-AM for core–shell manufacturing offers improved mechanical properties and dimensional accuracy over conventional 3D-printed polymer. Operating parameters play an important role in forming the overall quality of the 3D-printed manufactured products. Here we use numerical simulations within the framework of computation fluid dynamics (CFD) to identify the best combination of operating parameters for the 3D printing of a core–shell polymer strand. The objectives of these CFD simulations are to find strands with an ultimate volume fraction of core polymer. At the same time, complete encapsulations are obtained for the core polymer inside the shell one. In this model, the deposition flow is controlled by three dimensionless parameters: (i) the diameter ratio of core material to the nozzle,  Additive manufacturing (AM) has introduced several advantages over conventional methods, such as shortening the design manufacturing cycle, lowering production costs, and increasing the degree of automation ,2. AmongTo overcome some of the mentioned drawbacks, a novel material design approach, namely core–shell structured filament, has recently been developed . In thisProcessing conditions affect the mechanical properties of ME-AM-fabricated parts, fabrication time, and the manufacturing resolution. Strand-to-strand distance plays a crucial role in the mechanical strength, and porosity of the fabricated parts ,13. DepeNumerical simulation has been widely employed as a predictive tool to analyse various manufacturing processes  and provIn this study, the deposition flow of a core–shell polymer strand is simulated using an isothermal CFD model. Focusing on the deposition flow immediately after the deposition of extruded polymers on the build plate enables us to fully understand the effects of various parameters—including the normalised gap between the extruder and the build plate, the velocity ratio of the moving substrate to the average velocity inside the nozzle, and the diameter ratio of core to the nozzle—on the encapsulation of core inside the shell matrix. As an example, full encapsulation is shown in layers two and three of In this article, a core–shell strand extruded from a printing head and deposited in a moving build plate is simulated using a CFD model. The following computation model is adopted to investigate the effects of various parameters on the encapsulation of core into the shell matrix, and the following principles are applied.p is the pressure, The material extrusion is generally governed by the Navier—Stokes equations, accounting for mass and momentum conservation. Given that the deposition flow of plastic materials has a deficient Reynolds number  are solved using a coupled pressure–velocity scheme with the implicit time-marching approach and the PRESTO scheme for pressure discretization. Moreover, the Green-Gauss node-based scheme is employed to evaluate gradients, and the QUICK scheme is selected to discretise the convective terms. The volume fractions of the molten polymers and air inside the control volumes are also solved using the implicit modified HRIC scheme . FurtherD is divided into two parts: the inner one (with a diameter of d) for the extrusion of the core polymer and the outer for the shell polymer. The nozzle is positioned over the build plate at the distance of t—the so-called extruded layer height. In the simulations, the nozzle head is fixed over the build plate, moving with the constant velocity of V. The molten shell and core resins enter the cylindrical nozzle with the same average extrusion volumetric flux of U.The geometry of the computational model, represented in The top surface of the nozzle is considered an inlet boundary condition with a fully developed velocity profile. The no-slip boundary condition is applied on all solid walls of the numerical model—i.e., build plate and the nozzle wall—so that the materials fully adhere to them. The numerical model’s remaining external surfaces are prescribed as an outlet boundary condition, where the extruded materials are free to exit the computational domain. Only half of the domain is solved with a symmetry boundary in the In this study, the extruded material’s deposition flow is simulated for various printing parameters, presented in Assuming the creeping flow, the flow’s viscosity and density do not affect the results of the simulations. However, their value was included in Considering the assumptions mentioned above, three dimensionless parameters can entirely determine the deposition flow: the velocity ratio ng speed . Given tThe performed simulations include a range of operating conditions, from a slow printing speed with a small gap and a medium flow rate of polymer to a fast printing speed with a large gap and high polymer flow rate. l et al. . The difFurthermore, comparing cross-sections obtained from operating conditions in which stigated , this stTo have a deeper insight, first, cases with stigated . For t/D. As the velocities of extrusion of core and shell resins are also equal, it can be concluded that the volumetric flow rate is the same and, thereby, the volume of extruded core and shell is almost equal to 50 vol% for each one in The encapsulation occurred in a case with Finally, numerical cases are studied in detail from the point of view of the offset between the centres of the core and the overall strand (or the shell centre)—In simulated cases with In this study, the deposition flow of an ME-AM-manufactured core–shell structured strand was simulated. Here, a manufacturing process in which the core polymer embedded into the shell inside the heated printing head and the resulting core–shell structure immediately deposited onto the build plate was simulated. The objectives were to find strands with the highest volume fraction of the core to maximize the dimensional accuracy of the resulting strand, the full encapsulation of the core inside the shell resin to maximize the improvement of interdiffusion of polymers between adjacent layers, resulting in the improved interfaces, through altering printing parameters, as well as to minimise the offset between the core centre and the strand centre in order to reduce anisotropy in the structure. Three dimensionless parameters, which included the velocity ratio The results showed that increasing Although some cases offered appropriate cross-sections from the point of view of encapsulation alone, they may suffer from some serious deficiencies, including high porosity and low inter- and intralayer bond line densities, when they are put beside and on top of each other to form a mesostructure. Hence, it is proposed to simulate the successive deposition of strands in order to assess the effect of different operating parameters on the properties of the formed mesostructure for future work.


Including an active participation of stakeholders along the transportation decision-making process is increasingly recognized as a necessary condition for reaching successful and high-quality decisions. This paper presents a framework for deciding on the appropriate transportation strategy for a supply chain from a multistakeholder perspective. It consists of three steps: (1) defining the transportation-strategy decision-making context and the objectives that must be achieved; (2) analyzing the actual transportation strategy regarding its three components: transportation network; transportation mode; and transportation insource/outsource, as well as identifying the stakeholders interested in the study; and (3) conducting a group decision making regarding each transportation strategy’s component, while involving the key stakeholders and taking into account the specificities of transported products. The proposed framework is then applied to a real case of the Moroccan public pharmaceutical supply chain, which has different features that distinguish it from other supply chains including its importance, urgency, and regulation. We employed the DELPHI method to determine the key stakeholders that should be involved in the decisional process. After that, we applied the group AHP method for selecting the appropriate transport-network design option while involving the identified key stakeholders. As one of the major logistical drivers, transportation has a large impact on both responsiveness and efficiency of the supply chain . By ferrIn today’s constantly changing environment, knowing how to successfully navigate these changes and make the appropriate and effective transportation decisions to properly make the products arrive safe to customers at right time, right place, and right cost is a must . With thMany authors ,5,6 claiProcess management is concerned with the overall planning and coordination of the process. It structures the process into different stages. The theorists claim that the number of steps involved in the decision-making process varies depending on the nature of the problem . In gene-Problem identification: The first stage of the process involves defining the problem to be addressed ,11. It i-Option generation: This stage involves the formulation of options and alternatives that look likely to achieve the objectives defined in the previous step. It includes inputs from key stakeholders ,9.-Option assessment: This stage includes a technical analysis of each option to determine to what extent each option meets the stated objectives. In order to assess the different strategic alternatives, a multicriteria decision analysis (MCDA) can be applied. Ishizaka and Labib  claimed -Formal decision making: The decision is made by taking into account the views of stakeholder groups.-Implementation: This will include a process management plan that defines the detailed program of activities and schemes.-Monitoring and evaluation: This assesses the outputs and outcomes of the implementation against the process’s objectives.These stages are as follows:Stakeholder engagement covers a wide range of tools that can be used to ensure appropriate stakeholder involvement in all stages of the project decision-making process. Stakeholder’s participation in transportation decision-making process is emerging as a basic component for reaching successful and high-quality decisions ,14.According to the literature ,9, some The stakeholders are defined as any individual or group of individuals that can influence or are influenced by the decisions to be made . Stakeho(i)-Financial barriers: These are the barriers relating to the funding of a project.-Legal barriers: These concern the legal regulation and requirements that inhibit the implementation of decisions to be made.-Institutional barriers: These concern the rules and norms that stakeholders use to organize all forms of repetitive and structured interaction between them.Contextual barriers which include the financial, legal, and institutional barriers.(ii)-Management barriers: These include any barriers relating to management of the decision-making process.-Communication barriers: These concern the problems associated with achieving consensus between stakeholders on possible courses of actions.Process barriers which can occur at any stage of the process, including:Barriers: A successful transportation process management recognizes the potential barriers that may restrict the scope of the project or hinder project completion. According to Kelly et al. , there aIt has only been in more recent years that the stakeholders have become more engaged in making the appropriate transportation decisions and invited to give their ideas and express their needs and concerns . The awaTherefore, transportation decision making is considered as a highly complex process, requiring the participation of multiple concerned stakeholders with different interests, expectations, and varying perceptions .Several research works can be found in the literature that cover the topic of designing a transportation decision-making process. They are generally carried out to provide high-quality transportation decisions. Cascetta et al.  proposedIn other work, Le Pira et al.  proposedFurthermore, Macharis et al.  proposedIn addition, reference  proposedThe analysis of these different transportation decision-making processes has shown the existence of many points of similarity. All of these processes involve a similar number of steps from the identification of the problem to be addressed, through the generation and assessment of alternatives to the implementation of the chosen alternatives and the monitoring of their impacts. Considering stakeholder participation and interaction in the process, all the previously described models have shown a vital interest in involving the stakeholders in all the phases of the process because of its benefits in making successful decisions. They considered that interaction is fundamental to the success of the decision-making process, because it allows one to increase the degree of consensus of the collective decision.However, we have noticed that these studies do not deal with determining decisions regarding the transportation in a supply chain. We therefore determine a lack in establishing a decision-making process that helps in deciding on strategic transportation decisions in a supply chain.Moreover, the transportation of pharmaceutical products, in particular, represents one of the most complicated operations in the pharmaceutical supply chain because of the sensitive nature and the specific characteristics of pharmaceuticals that require a high degree of attention during transportation . ImpropeIn this paper, we are interested in presenting a participatory framework for deciding on the appropriate transportation strategy for a pharmaceutical supply chain while involving the interested stakeholders.The rest of this paper is organized as follows: The suggested framework is presented in Developing a successful supply-chain transportation strategy involves decision making regarding several components. Choosing the appropriate transportation mode, designing the transportation network, and deciding which part of the transportation process will be outsourced and which one will be insourced are the major decisions that must be made, while involving the relevant stakeholders and taking into account the specificities of products to be transported, in order to design an effective transportation strategy.Based on the literature review, we proposed a transportation strategy decision-making process that effectively involves the stakeholders in all the phases of the process in order to help the decision makers in making the appropriate and the most shared decisions. The group decision-making process involves several steps; the first one is analyzing the identified stakeholders to retain the most critical ones to be fully engaged in the decision process in order to satisfy their needs and expectations. The second step consists of identifying the problem associated with each component and the objectives that must be achieved in order to reach the final goals related to the transportation strategy. The third step involves the generation of the alternative options, the determination of the different criteria, and then a multicriteria group decision analysis (MCGDA) method is applied in order to determine the best option that meets the stated objectives, while taking into account the views of stakeholder groups. In fact, the reason behind the choice of the multicriteria group decision-making analysis method to be applied for deciding on transportation strategy is due to the presence of different stakeholders with multiple conflicting criteria involved in the decision-making process.The fourth step of the proposed framework includes all necessary preparatory resources needed in order to bring the selected option to the point of operation; this stage can be supported by the participation of the stakeholders. Finally, an evaluation of the outputs of the implemented alternative is undertaken in order to determine whether the objectives have been met.In the following section, we present a literature review regarding the key components of the proposed transportation strategy decision-making process, with the intent of creating a clear understanding of the problem at hand, as well as analyzing and defining the relevant criteria used in the literature in evaluating the problems associated with these components.In this section, we briefly review literature devoted to the key components of the suggested transportation strategy decision-making process: namely, the design of the transportation network, the choice of the appropriate transportation mode, deciding on transportation outsourcing/insourcing, products portfolio analysis, and management of stakeholder engagement. We also define the relevant criteria used in the literature in evaluating the problems associated with these components.The movement of products from a source to a destination can be undertaken using one or a combination of the following modes of transport: air, package carriers, truck, rail, water, and pipeline . Each ofRail or railway transportation is the cheapest, quickest, and best suited for carrying heavy, bulky, and not very time-sensitive goods over long distances. Some of the advantages are constancy, low-cost guarantee, and greater reliability, and they are not affected by the weather and traffic conditions. The main disadvantages are inflexibility and specified routes between fixed terminals; moreover, they do not stop at intermediate points .Sea transportation is suited for carrying very large and bulky loads at low cost. However, the damage risk is high, transit times are long, and there is a limitation and inflexibility with regard to finding appropriate ports.In addition, air transportation is the most convenient mode, when a slow speed is unacceptable. It is, however, the most expensive mode .Of all the transportation modes available to use in the movement of products, trucking, is still the single most widely used mode . A varieFull truckload shipping is described as a transportation chain with only one link, where source and destination are peer-to-peer connected through a direct, noncombined transportation , so thatOn the other hand, the term LTL is appropriate when transporting shipments in small lots that do not fill an entire truck . Less-thFurthermore, in order to take advantage of the benefits offered by various transportation modes and compensate for deficiencies, shippers often use more than one mode to transport products. The intermodal transportation, as this integrated approach is called, has become increasingly common and applicable. It provides a flexible response to the changing supply-chain management requirements in global markets and distribution systems .-Customers/suppliers density and distance (C1): This criterion should also be considered when deciding on the degree of temporal aggregation to use when supplying customers. Moreover, the selection of the mode to ship goods depends on the accessibility and the geographic location of the customers/suppliers.-Shipment size (C2): Decision makers should take into consideration the weight, density, and shape of the products as well as its packaging in choosing the appropriate transportation mode. For instance, lightweight products can be transported by land or air, while heavier products are suited for railroads or waterways.-Requirements associated with the type of the freight to ship, such as goods for fast consuming (highly perishable) or frozen products.Financial value of the transported freight.Product characteristics (C3): This criterion is involved with product-related features:-Delivery time (C4): Duration of the overall transportation process.-Transportation cost for shipment of products from source to destination.Cost of damages to freight incurred at the transportation or transshipment stages.Information system cost to provide coordinated transportation.Total cost (C5): This contains all cost factors that are involved in the transportation process.-The ability to meet the unexpected changes in demand.The ability to change the volume and weight capacity of the transportation vehicles.The ability to change the transportation route at any time during transportation.Flexibility (C6): This criterion handles the unexpected changes in demand during the transportation, capacity flexibility, and routes flexibility.-Probability of avoiding damage and loss of quality of goods.The accidental rate in a determined time period.Safety criteria (C7): This involves the safety problems related to the transportation process.In the selection of a suitable mode from the different modes previously described to use for each part of the transportation network, all the characteristics related to the concerned mode of transportation have to be considered. Under certain conditions, the choice of the suitable transportation mode may seem obvious, but a comparison that depends on a variety of criteria may be nevertheless required. As shown in In today’s constantly changing market, managing transportation is a key factor for a more efficient and cohesive supply chain. Deciding which part of the transportation process will be outsourced and which one will be insourced is one of the most important strategic decisions that have a large impact on the total supply-chain profit .In fact, transportation managers should decide whether to outsource the entire transportation process or to outsource a part of it, and they should also determine the level and extent of outsourcing of each part based on the growth in total supply-chain profitability . OutsourRecently, outsourcing has become the most preferred strategic option for the most important structures in order to keep focus on their core businesses . However-Total cost (C1): Estimating the cost of outsourcing the transportation or keeping it in-house is an important criterion to be taken into account while making the decision. A deep cost–benefit analysis must be done in order to make the right decisions.-Core competency (C2): Outsourcing is a very helpful tool which enables the company to concentrate on its own core competencies and to increase its efficiency and profits.-Technological capability (C3): Outsourcing can offer the possibility to benefit from the new technologies that meet the changing market conditions, and also to access the latest technology and external skills and talent.-Flexibility (C4): Outsourcing allows organizations to create lean supply chains that can quickly change to meet changing requirements, demands, or technologies.-Responsiveness (C5): Outsourcing improves the responsiveness of the supply chain.-Quality (C6): Outsourcing offers an improvement of the quality, in the sense of offering a specific level of technological capability that is required to meet the minimum requirements for the product quality.-Timeliness (C7): The outsourcing decreases the delivery time when the customer orders are small in the sense of aggregating different firm’s orders.-Information security (C8): The outsourcing can lead to the failure of the product traceability and the leakage of the information.-Quality Control (C9): Insourcing offers the advantage of a high degree of control and visibility over all the operations.-Product complexity and specificity (C10): In making the insourcing/outsourcing decisions, it is necessary to take into account the nature of product to ship in order to avoid damage.-Risks (C11): Risks related to outsourcing, such as risk of strategic information leakage and risk of the product leakage-Shipment size (C12): Outsourcing is a better option when shipment sizes are small, whereas owning the transportation fleet is better when shipment sizes are large.Choosing either to outsource or to insource is a complex decision-making process, arising out of a variety of several factors. Many authors present different factors critical to deciding between outsourcing and insourcing. A deep analysis of the literature devoted to the insourcing/outsourcing decision-making process sorted different criteria that are mainly used by the decision makers in making the right insourcing/outsourcing decisions See . These iA summary of the reviewed studies on the outsourcing/insourcing decision-making process under considering the different criteria that have been already discussed is shown in Moreover, the involvement of the public and the stakeholders is another important dimension that must be taken into account in making the insourcing/outsourcing decisions.The design of a transportation network affects the performance of the whole supply chain by implementing the infrastructure in which several transportation decisions are made . It usedThere are a variety of transportation-network design options ,63.(a)Direct-shipment network: The products are transported directly from suppliers to customers.(b)Direct shipping while applying milk runs: The goods are either transported directly from one supplier to multiple customers or from many suppliers to one customer.(c)All shipments via central distribution center (DC) with inventory storage: Products are shipped to customers via a distribution center which is built for each region of the country. The products are held in inventory at the distribution center.(d)All shipments via central distribution center (DC) with crossdock: Products arrive from many suppliers into inbound trucks to be transformed into smaller shipments that are then loaded onto trucks going to each customer.(e)Shipping via distribution center (DC) using milk runs: Products are shipped from suppliers to distribution centers to be then transported on milk-run to each customer by consolidating small shipments.(f)Tailored network: Combination of different transportation-network options based on customer and product characteristics.They include the six options given below See :(a)DirecChoosing the appropriate transportation-network design option is one of the most important operations that transportation managers should focus on. In this sense, we have proposed in a previous work  a framew-Delivery time (C1): The actual time between placing an order, and receiving the delivered product;-Number of trucks (C2): The use of milk run reduces the number of trucks utilized for shipping pharmaceutical products;-Transportation cost (C3): Consolidating shipments lowers transportation cost;-Information system cost (C4): The use of milk runs increases the cost of an information system, because it requires a significant degree of coordination;-Size of served area (C5): The design of the appropriate transportation network must be suited to the size of the area to be served;-Transportation risk (C6): Risk is the probability of harm or damage occurring from exposure to a hazard, and the likely consequences of that harm or damage. It may refer to the concept that the transportation plan is not reliable in practice. It also refers to the potential impact on environment and human, for example, when it comes to the transportation of hazardous materials. Transportation risk reduction is one of the major interests of the public and governments around the globe . Therefo-Demand satisfaction (C7): Maximizing the satisfaction of customer demands amounts to maximizing the quality of the transportation service, which is influenced by improving the timeliness of transportation process  and maxi-Flexibility (C8): The use of the milk run increases the flexibility;-Regulatory criteria (C9): Each activity in the transportation process should be carried out according to requirements related to the specificities of transported products.An in-depth analysis of the literature has allowed us to draw up a list of a variety of criteria that have been mainly used in designing transportation networks. These include:A summary of some reviewed studies on the design of the appropriate transportation-network option, considering the different criteria that have been already discussed, is shown in Stakeholder management is regarded as an effective approach to manage conflicting stakeholder interests and to improve the quality of decisions to be made by taking into account the diverse interests of all legitimate stakeholders ,75.The procedures involved in stakeholder-management process have been widely discussed in existing literature. Summarizing these procedures, we have considered in our previous work , the staAs depicted in Several researchers have highlighted the importance of managing the stakeholder participation for improving the quality of the transportation decision-making process. We have provided, in our previous work , a summaAnother factor that often is left out of discussions on transportation decision making is looking at the actual physical characteristics of what is being shipped, such as type of product, weight, value, perishability, handling characteristics, and packaging ,80. SeveIn this section, we apply our suggested approach to design a transportation strategy for the public pharmaceutical products supply chain in Morocco. In the first stage, we identify the context of the study, and we define the transportation strategy’s objectives that must be achieved. In the second stage, we analyze the actual transportation strategy to help create a clear understanding of what needs to be decided. After that, we identify all the stakeholders that may affect or be affected by the design of the Moroccan public pharmaceutical transportation strategy. Finally, we conduct a decision-making process regarding the design of the transportation network, while involving the relevant stakeholders and taking into account the specificities of pharmaceutical products, in order to design a successful transportation strategy.In recent years, Morocco launched a number of actions and strategies to enhance access to health services and improve health outcomes for the whole population. In this context, the Moroccan ministry of health had begun to establish a series of actions to improve the level of accessibility and availability of pharmaceutical products for Moroccan citizens.With the generalization of basic health coverage in 2012, public hospitals must meet the increasingly important demand for care and must face a population that has become more demanding. To adapt to this strong demand, the annual budget allocated to the acquisition of pharmaceuticals has dramatically increased from 300 million dirhams in 2003 to more than 2 billion dirhams in 2018 .Faced with this situation, the current logistic circuit seems to be saturated and no longer adapted to the new challenges. For this reason, the Moroccan Ministry of Health expressed the need to develop an effective and efficient pharmaceutical supply chain through the proposition of strategic and tactical decisions with respect to the following six dimensions: (1) distribution networks, (2) facilities and installations, (3) inventory management, (4) transportation, (5) outsourcing (public–private partnership), and (6) the new technologies and information system .Supply division: Responsible for the consolidation of requirements of the different health institutions, the tenders’ launch, the reception, the storage, the distribution of pharmaceutical products, and the administrative management, as well as the supply monitoring.Pharmaceuticals suppliers: 40 pharmaceutical laboratories and 20 suppliers of medical devices.Central warehouses: which are four in number .Regional warehouses: They include four completed  and four under construction .Public health institutions (customer zones): which are 159 in number, including 77 provincial and regional hospitals (PH) and (RH) and 82 provincial delegations (PD), which is in charge of supplying 2750 basic healthcare institutions.As can be seen from Pharmaceutical products should be available in public health institutions at all times in sufficient quantities, delivered and administered safely. In this context, Morocco is making a major effort at increasing the budgets allocated to the acquisition of pharmaceutical products and developing techniques and measures providing health institutions the means to participate in defining their needs . DespiteTo address these problems, different decisions should be made in relation to the different flows of goods between suppliers and customers including facility location, production, inventory, and transportation ,63.Transportation is one of the major supply-chain drivers, as it is responsible for linking the whole supply chain from suppliers to customers. In this sense, we are going to design an appropriate transportation strategy that improves the efficiency and responsiveness of the Moroccan public pharmaceutical supply chain.Transportation of pharmaceutical products is the most important part in a logistics chain because the products being transported are for human consumption. Therefore, it is necessary to develop an appropriate transportation system to ensure that the medicines arrive to consumer in perfect conditions.In the Moroccan public sector, the deliveries of pharmaceuticals are made by the supply division of the Ministry of Health in a planned way with typically four deliveries per year with an annual volume of 25,000 tons of products.The products are transported by using small trucks or small vans from suppliers to the storage sites of the Moroccan Ministry of Health, which are divided into central and regional warehouses. The central warehouse usually has copious storage capacity, and it is in charge in delivering the received products, either directly or via regional warehouses, to the customer zones, including provincial and regional hospitals (PH and RH) and provincial delegations (PD) by using smaller vans and cars.The distance for the transportation of pharmaceutical products is about 700,000 km yearly. The supply division is responsible for delivering pharmaceuticals to provincial and hospital pharmacies through contractual transportation companies. Meanwhile, basic healthcare facilities are delivered by the delegations’ own transportation means. The trucks used for transporting products have different capacities depending on the demand to be delivered .The Moroccan pharmaceutical-products transportation system knows the intervention of a multiplicity of stakeholders with different levels of competences and interests. As depicted in Designing the appropriate pharmaceuticals transportation strategy involves various groups of stakeholders with different interests and wants, which makes achieving their satisfaction a difficult objective to realize. In this sense, it is of great importance to prioritize them to retain the most critical ones to be fully engaged in the design process in order to satisfy their needs and expectations.We have used the DELPHI method  to complWe have been inspired by the work of  in applyIdentification of panel of experts: They should have relevant knowledge and experience in their respective fields. In this manner, 16 people were identified and contacted either directly or via email. Through feedback, 10 of them expressed their agreement to be part of the panel as shown in Design the questionnaire: Firstly, we demanded to each expert to consult the established list of stakeholders and to add others that may be considered pertinent. Then, we outlined some dimensions regarding the transportation of pharmaceuticals to be considered in the questionnaire, so the experts could have a common understanding of the study context . After tConsultation of the experts and analysis of results: The questionnaire has been administered to each expert by email or via direct contact. Then, the questionnaires are returned to be analyzed, aggregated, and shared with the different experts. Several rounds of questionnaires can be sent out to the group of experts until arriving at a group consensus. The degree of consensus among experts is assessed using Kendall’s W coefficient of concordance. This coefficient measures the extent to which the experts agree on their rankings, it ranges between 0 (Perfect disagreement) and 1 (perfect agreement). For a value of W less than 0.7, the questionnaire should be sent back to experts . All expTo analyze the experts’ answers, we started by calculating the sum of the scores assigned to each stakeholder regarding their “having an influence on” and “being impacted by” the different mentioned dimensions. Then, the completed experts’ responses were analyzed using IBM SPSS Statistics software . The first Delphi round indicated values of W less than 0.7. Hence, the questionnaire was sent back a second and third time to each expert for new responses, accompanied by his or her own rating in the previous rounds and the consolidated result of the panel’s responses. The third round showed an increase of W, which exceeded 0.7, indicating a better degree of consensus .For a better understanding of this prioritization, we have put the stakeholders in the influence/impact matrix proposed by  Figure .As can be seen from However, it should be noted that the identified stakeholders and their obtained classification can be updated at regular intervals over time, according to the happened changes in the environment.Moreover, designing the appropriate pharmaceuticals transportation strategy requires decision making regarding different components: designing the appropriate transportation network, choosing the suitable transportation mode, and deciding which part of the transportation process will be outsourced and which one will be insourced, while involving the relevant stakeholders and taking into account the specificities of the pharmaceutical products. In this paper, we are interested in designing the transportation network.In the following section, we conduct a decision-making process to choose the most appropriate transportation-network design option for the Moroccan public pharmaceutical supply chain while involving the main stakeholders and taking into account the specificities of pharmaceutical products.We have proposed, in a previous work , a frameHowever, we realized that the analysis of the transportation system should involve many social groups and different aspects. Accordingly, we have decided to engage the identified key stakeholders in choosing the appropriate transportation-network design option for the public pharmaceutical supply chain in Morocco.✓(TN1): Products shipping via central/regional warehouses;✓(TN2): Products shipping via central/regional warehouses by using milk run from suppliers to central warehouses;✓(TN3): Products shipping via central/regional warehouses by using milk run from regional warehouses to a supply chain’s customers;✓(TN4): Products shipping via central/regional warehouses by using milk run from suppliers to central warehouses and from regional warehouses to a supply chain’s customers.Four transportation-network design options were proposed in :✓(TN1): The choice of the appropriate transportation-network design option is based on a set of criteria (Cj). Based on the previous list of criteria determined according to the literature , six cri-Delivery time: the actual time between placing an order and receiving the delivered product.-Number of trucks: the use of milk run reduces the number of trucks utilized for shipping pharmaceutical products.-Transportation cost: consolidating shipments lowers transportation cost.-Information system cost: the use of milk runs increases the cost of information system because it requires a significant degree of coordination.-Criteria to maximize:-Regulatory criteria: Transporting pharmaceutical products should be carried out according to requirements of the drugs act in order to avoid the risk of impacting the safety, quality, and effectiveness of pharmaceuticals.-Flexibility: Ability to respond to unexpected events in order to satisfy the customer’s specific needs.Criteria to minimize:Six key stakeholders were contacted representing the six main interest stakeholder groups which have already been mentioned. Through feedback, only five stakeholders expressed their agreement to participate in the decision-making process: (1) Ministry of Health (S1), (2) Ministry of Transport (S3), (3) public healthcare facilities and healthcare personnel (S7), (4) healthcare industry (S8), and (5) patients (S11). Stakeholders were individually contacted and approached directly or through emails explaining the objective of the study with a detailed description of the four different alternatives in terms of strengths and weaknesses. Then, they were asked to confirm the established list of criteria. Nevertheless, deciding io the appropriate transportation network while engaging the key stakeholders and taking into account the different criteria needs to be tackled with a multicriteria decision-making approach.Many MCDA methods exist, but the analytic hierarchy process (AHP), proposed by , is usedIn addition, as different persons affect the decision-making process, the AHP method has been adapted to be applied in group decision making. Hence, it is considered a useful method to support stakeholder engagement in making appropriate decisions ,98.There are different ways to combine the preferences of the decision makers into a consensus rating : accordiIn the following section, we applied the different steps of the AHP method  to selecFirst, a hierarchical structure of the problem was modeled . StartinThen, the stakeholders’ weight was evaluated from the stakeholders themselves (self-assessed weights) through a questionnaire. The judgements were justified by the analysis of the results of DELPHI method .After that, each of the stakeholders was asked to make pairwise comparisons for the different alternatives against each criterion and for the different criteria while verifying the consistency. Then, an aggregation of the priority vectors of different alternatives, while taking into account the criteria weights, was performed in order to obtain the ranking of alternatives according to each stakeholder b.As can be seen from In the following section, aggregation of individual priorities has been performed, while applying the weighted arithmetic mean method to derive a collective decision as an output of the AHP methodology . A consuTransportation is at the heart of supply-chain operations, as it is the responsible for ensuring the movement of products from supply sites to customers. Deciding on the appropriate transportation strategy requires the participation of multiple stakeholders with different interests and expectations. The main objective of this paper was to propose a framework for designing an appropriate transportation strategy for a supply chain from a multistakeholder perspective. This research work was born from the need of the Moroccan Ministry of Health in improving the efficiency and the responsiveness of the pharmaceutical public supply chain in order to satisfy the increasing demand of pharmaceuticals. We have applied the suggested framework for deciding on the appropriate strategy for transporting pharmaceuticals in the Moroccan public sector.Patients (S11): They are at the core of the health system. The World Health Organization emphasized to put the patients at the center of the healthcare system by meeting their needs and expectation . The patMinistry of health (S1): It plays a crucial role in the design of the pharmaceuticals transportation strategy through strengthening the Moroccan’s healthcare system and having the overall responsibility for the management and development of that system.Public healthcare facilities (S7): They are the primary means of the healthcare delivery to patients. They play a potential role in the design of the pharmaceuticals transportation strategy through their location in the distribution network, their respect of patient’s preferences, and their ability to ensure the availability of pharmaceutical products to patients.Ministry of Transport (S3): It plays an important role in the design of the pharmaceutical transportation strategy, as it is responsible for transportation within the Moroccan’s country including overseeing road safety and developing government transportation policies.Healthcare industry (S8): It plays a key role in the healthcare system as it is the responsible of the production and the distribution of healthcare products, especially the pharmaceuticals, to the different healthcare institutions.Local authorities (S5): They represent a key participant in the implementation of national healthcare strategies.First, an analysis of the current pharmaceuticals supply chain was carried out in order to have a clear understanding of the actual situation, to determine the multiple daunting challenges faced by the current supply system, and to define the objectives that must be achieved to meet the Ministry of Health‘s expectations. Then, we analyzed the current transportation strategy regarding its three components: transportation network, transportation mode, and transportation outsource/insource. We established a list of the different stakeholders interested in the design of the pharmaceuticals transportation strategy for the Moroccan public sector. The identification of stakeholders was done based on the literature review conducted on previous studies on healthcare and transportation sectors, and also, through the analysis of some conducted interviews and work meetings with the professionals of the Ministry of Health. These stakeholders were prioritized, while applying the DELPHI method, according to their degree of “having an influence on” and “being impacted by” the design of the transportation strategy of the pharmaceutical products in the Moroccan public sector. The findings have allowed the identification of six key stakeholders to be fully engaged in transportation strategy decision-making process:We contacted six stakeholders representing the identified key stakeholder groups for participating in the transportation strategy decision-making process. Through feedback, only five stakeholders expressed their agreement to participate. (1) Ministry of Health (S1), (2) Ministry of Transport (S3), (3) public healthcare facilities and healthcare personnel (S7), (4) healthcare industry (S8), and (5) patients (S11).After that, we applied the AHP Group method to choose the appropriate transportation-network design option for the Moroccan public pharmaceutical supply chain while involving the identified key stakeholders into. The results showed that applying the milk-run option from suppliers to central warehouse, as well as from regional warehouses to customer zones, is the most suitable transportation-network option for shipping the pharmaceutical products in the Moroccan‘s current public distribution network.Deciding on the others transportation strategy’s components while involving the relevant stakeholders into choosing the appropriate transportation mode, as well as deciding which part of the transportation process will be outsourced and which one will be insourced.The proposed transportation strategy decision-making process was conducted while engaging five key stakeholders that represent five key stakeholder groups: namely, (1) Ministry of Health, (2) Ministry of Transport, (3) public healthcare facilities and healthcare personnel, (4) healthcare industry, and (5) patients. However, in order to improve the quality of the decisions to be made, we look for involving others performing persons representing the key stakeholder groups.Having a clear insight on the stakeholders involved in the decision-making process and the interactions among them is helpful in guiding an effective participation process aimed at consensus building among stakeholders. In this sense, we propose, for our future work, to use a modeling approach based on participatory modeling methods such as: the social network analysis (SNA), discrete choice models (DCM), and agent-based models (ABM).Improving the proposed framework to be adapted for designing a smart transportation strategy through the employment of the digital and telecommunication technologies like information and communications technology (ICT) and the Internet of things (IoTs). The design of such transportation system will have numerous benefits including improving the life quality of the entire population and maximizing the sustainability and environmental conservation .Another issue that deserved investigating is to use other multi-criteria decision analysis (MCDA) methods adapted to be applied in the group decision-making context participation to evaluate and analyze the performance of the decisions to be made.The findings of this research work raise some interesting research questions and create promising perspectives for future work. We summarize below a list of some potential research venues:In this paper, we presented a framework for designing an appropriate transportation strategy for a supply chain while involving the concerned stakeholders and taking into account the specificities of the transported products.This framework was applied to a real case study of the Moroccan public pharmaceutical supply chain. First, we defined the transportation strategy decision-making context and the objectives that must be achieved. Second, we analyzed the current transportation strategy regarding their three components: transportation network, transportation mode, and transportation insource/outsource. Then, we identified the stakeholders interested in designing the pharmaceuticals transportation system. Finally, in the third step, we conducted a group decision-making process regarding the transportation-network design component. In this sense, the identified stakeholders were first analyzed and hierarchized while employing the DELPHI method to determine the key of them. After that, we have applied the Group AHP MCDA method for selecting the appropriate transportation-network design option while involving the identified key stakeholders into. The results showed that shipping products via central/regional warehouses with using milk run from suppliers to central warehouses and from regional warehouses to a supply chain’s customers is the most suitable transportation-network option for shipping the pharmaceuticals in the Moroccan’s public pharmaceutical supply chain.Future work will deal with choosing the appropriate transportation mode, as well as deciding which part of the transportation process will be outsourced and which one will be insourced, while involving the relevant stakeholders.