Analysis of Dynamic Mechanical Effects of Single-Crystal Silicon Anisotropy on MEMS Fuze Safety and Arming Systems under High Strain Rates

Silicon-based MEMS fuze safety and arming systems face significant dynamic failure risks under high-g shock conditions in operational environments. The primary cause lies in the insufficient understanding of the coupling mechanism between the anisotropic properties of single-crystal silicon and high strain-rate loading, which severely constrains reliability design and performance optimization. This study investigates the dynamic mechanical behavior of single-crystal silicon under high strain rates, focusing on failure mechanisms induced by material anisotropy in MEMS fuze systems subjected to high-g impact. Dynamic mechanical parameters of single-crystal silicon along three principal crystallographic orientations, <001>, <110>, and <111>, were obtained via split Hopkinson pressure bar (SHPB) tests. The results reveal significant strain-rate sensitivity and orientation dependence in both elastic modulus and ultimate strength. Based on experimental data, a finite element model incorporating crystallographic orientation was developed to systematically analyze the effects of crystal orientation, impact amplitude, and excitation frequency on the dynamic stress response of the fuze's setback safety mechanism. Key findings include: structural stresses simulated with high strain-rate constitutive parameters consistently exceed those derived from quasi-static parameters, with a maximum difference of 32.1%; crystal orientation significantly modulates stress distribution; and the relationship between impact peak amplitude and stress response exhibits nonlinear growth. This research provides theoretical and data-driven support for the reliability design and crystal orientation optimization of silicon-based MEMS fuze safety and arming systems under high strain-rate conditions.