Discrete Element Modeling of the Shear Characteristics of Biomimetic Snake-Scale Interfaces

Biomimetic snake-scale interfaces exhibit pronounced shear anisotropy, demonstrating promising application potential in the optimal design of soil–structure interfaces. To elucidate the underlying mechanisms of this anisotropy, this study employs the discrete element method (DEM) to develop a ring shear model of the glass bead–biomimetic snake-scale interface. Based on the simulation results, the shear response and its micromechanical evolution under constant normal stress are analyzed, and the effect of normalized scale height H/d and its underlying mechanism are discussed. The results indicate that the biomimetic snake-scale interface exhibits significant directional shear differences, with cranial shearing yielding a higher peak shear stress than caudal shearing. Moreover, cranial shearing forms a thicker shear band, where particles adjacent to the interface are more prone to interlocking at the steep slopes of the scales, thereby establishing a stronger force chain structure. Furthermore, the scale height exerts a nonlinear influence on the interfacial strength. For the particle-size and scale-length conditions considered in this study, cranial shear strength exhibits an apparent threshold response with increasing H/d, which is associated with particle climbing and trapping mechanisms, whereas caudal shear strength increases gradually. These findings may provide a useful reference for the design and potential engineering application of biomimetic snake-scale interfaces.