Shear Jamming Transition in Soft Composite Solids

Soft composites are widely used in the modern materials industry and play a significant role in emerging engineering fields such as soft robotics, wearable medical devices, and intelligent responsive materials. In particular, recent studies have shown that densely filled soft composites can exhibit nonlinear mechanical properties similar to biological tissues. However, due to the multiscale complexity and structural heterogeneity of soft composites, classical theories struggle to accurately describe the interplay between particle interaction networks and the elastic matrix in dense limits. To address this issue, this study systematically investigates the role of shear jamming in the nonlinear mechanics of soft composites. Specific research achievements include: (1) By combining experimental studies with theoretical analyses of shear jamming phase transitions, a phenomenological model based on critical scaling laws was established, which accurately describes the shear stiffening behaviors of soft composites for different material parameters; (2) By controlling the coupling between shear jamming structures and the soft elastic matrix, multi-axis non-reciprocal responses was achieved. Furthermore, by integrating magnetic intelligent units with shear anisotropy characteristics, a spatiotemporally programmable mechanical non-reciprocal system was developed; (3) By designing the structural memory of shear jamming networks, a quantitative transition from particle-like systems to biological tissue-like enhanced behaviors was realized in soft composites. These studies provide new insights for addressing key challenges in dense soft composites and open new pathways for the development of mechanically intelligent materials.