Failure Modes in MicroNanosystems: Understanding Fatigue and Fracture Strength

This lecture delves into the failure modes in MicroNanosystems, focusing on fatigue and fracture strength. It covers the concept of fatigue as a cycle-dependent decrease in yield strength, the impact of fluctuating loads on materials like steel, and the engineering challenges in Si springs for shock tolerance. The discussion also includes the fracture strength of different poly-Si layers and the effect of temperature on fracture. The lecture provides insights into the endurance limit of materials, the rare occurrence of fatigue in silicon compared to metal MEMS, and the Weibull failure probability plot for poly-silicon layers at various temperatures.