Numerical Simulation of Novel MEMS Strain Sensor for Structural Health Monitoring

This paper presents the numerical simulation of novel Micro-Electro-Mechanical- System (MEMS) based piezoresistive strain sensor in order to monitor the localized strain in structures such as crack tips. The MEMS strain sensor developed in this study is made of single crystal silicon, and has 100 μm width and 400 μm length which prevents the strain gradient effect at the vicinity of stress concentration regions. The device has a novel U shape configuration where the open side of the U shape faces the crack tip and provides additional strain amplification. The silicon has piezoresistive property, which can have a gage factor reaching up to 165. Rigid substrate effect of silicon package on the strain sensor has been minimized based on the geometrical feature which has been used to amplify the stress in the sensor. The MEMS strain sensor has been optimized using COMSOL Multiphysics software, which enables the combination of multiple physics solutions in a single model, which are structural and electrical in this study.