Abstract

Soft composites offer new avenues for the design and fabrication of materials and devices that exhibit novel properties and functional behavior. Engineering the interplay between the geometrical structuring of constituent materials and the large deformation behavior of the soft matrix enables structural transformations and tunable properties. Here we explore the mechanics and the design of soft composites through analytical and numerical modeling as well as through experiments on physical prototypes fabricated using multi-material 3D printing. A first exemplar set focuses on both patterned and layered structures which exhibit deformation-induced pattern transformations. These structural transformations result in concomitant changes in a multitude of behaviors: giving superelastic and multilinear elastic response, enhanced mechanisms for energy storage, and the ability to manipulate wave propagation and alter phononic band gaps. Inspired by natural material systems, we also explore soft composite materials with alternating soft/stiff layered structures. The discrete anisotropic nature of these material systems are demonstrated to provide protective yet flexible armor and are separately found to be a novel design for soft actuators, transforming local compressive loading to large scale rotational motion. Also inspired by nature, a third set presents soft matrices augmented by stiff particles which yield a material with morphable surface topologies.