Mechanical non-reciprocity programmed by shear jamming in soft composite solids

Mechanical non-reciprocity, manifested as asymmetric responses to opposing mechanical stimuli, has traditionally been achieved through intricate structural nonlinearities in metamaterials. However, continuum solids with inherent non-reciprocal mechanics remain underexplored, despite their potential in applications such as wave guiding, robotics and adaptive materials. Here we engineer non-reciprocal mechanics in soft composite solids by using the shear jamming transition from granular physics. Through the control of the interplay between inclusion contact networks and matrix elasticity, we achieve tunable, direction-dependent asymmetry in both shear and normal mechanical responses. In addition to static regimes, we demonstrate programmable non-reciprocal dynamics by combining responsive magnetic profiles with the anisotropic characteristics of shear-jammed systems. This method enables asymmetric spatiotemporal control over motion transmission, a previously challenging feat in soft materials. Our work establishes a strategy for designing non-reciprocal matter, bridging granular physics with soft material engineering to realize functionalities essential for mechano-intelligent systems.