Cellular variable stiffness materials for ultra-large reversible deformations in reconfigurable structures

摘要

Structures that can physically adapt to fulfill many roles can enable a new generation of high-performance military systems. The key to achieving substantial benefit from shape-changing operations is large changes in structural geometry and stiffness. In this study, we demonstrate variable stiffness cellular materials capable of large global changes in area through local buckling modes. Furthermore, stiffness properties and Poisson ratios may be tailored to provide desirable structural reconfiguration properties such as negative Poisson ratio and highly anisotropic stiffness. However, stiffness properties of cellular materials are two to three orders of magnitude below their constitutive materials properties. Their elastic properties can vary considerably as a function of the applied strain level due to the redistribution of structural material within the cells. Another complication is the difficulty in controlling the local buckling mode due to sensitivity to boundary conditions and loading conditions.