Design and Genetic Algorithm Optimization of a High-Shock-Resistant MEMS Accelerometer Sensitive Structure for Automotive Airbag Applications

High-shock accelerometers are essential for automotive airbag systems, where sensors must detect extreme shock events while maintaining structural integrity. However, conventional MEMS structures often suffer from stress concentration and mechanical failure under ultra-high-g conditions. To address this, a novel capacitive MEMS accelerometer with a symmetrical four-quadrant, four-anchor spring-frame suspension is proposed. A genetic algorithm was used to optimize the connecting and support beam geometries, reducing their respective regional maximum Von Mises stresses by 39% and 21.7%. Finite element simulations show that the optimized structure withstands a 10,000 g shock with maximum Von Mises stress in the sensitive structure remaining below 1.2 × 10⁸ N/m² . The final design offers a ±480 g measurement range within a 700 μm × 700 μm footprint, demonstrating strong potential for high-reliability deployment in automotive airbag systems.