Characterization and Modeling of Layer Jamming for Designing Engineering Materials with Programmable Elastic-Plastic Behavior

Abstract

The use of layer jamming materials has promising applications in soft robotics and vibration control, where there is a need to have materials that can change their properties in situ. However, there is limited research on analytically modeling the plastic deformation response of layer jamming materials attributed to the level of cohesion between layers that controls the shear resistance to achieve variable mechanical properties in shear and bending deformation modes. In this paper, we present and validate a model for engineering layer jamming materials with programmable elastic-plastic properties. The model is validated using Digital Image Correlation (DIC) displacement measurements to track layer decohesion for the following test scenarios: (i) variable vacuum pressure, (ii) variable layered material, and (iii) variable transverse symmetry. To illustrate the utility of the model, we conducted a sensitivity study on a multi-material layer jamming specimen to identify the critical regions of a beam where greater interfacial adhesion can enhance the resistance of the beam to plastic deformation. The layer decohesion measurements are consistent with existing knowledge that for laminated materials, layer decohesion will initiate towards the free edge. However, it contradicts a previous assertion that in layer jamming materials, decohesion would initiate at the fixed end. With this model, we have a better understanding of how to design layer jamming materials to improve the performance of structures through variable compliance, load bearing capacity, and energy absorption.