Mathematical analysis of a new sensitive-to-shock automotive crash sensor

Davood Kalantari, Mohsen Mahdiani

In this study, mathematical analysis of a simple and new mechanical sensitive-to-shock automotive crash sensor is presented. The system includes a cantilever beam with a current-carrying wire. Due to the high acceleration generated in a crash, the beam breaks and cut the electrical circuit off. With cutting off the electricity, secondary activations can occur, including activation of the air bag system, unlocking doors and disabling the alarm system. The proposed system is lightweight, low-cost and seems to have acceptable accuracy. Analysis is based on the mathematical equations particularly the Laplace transform method. The results showed that if a hard plastic cantilever beam with height of 8 cm and cross-sectional area of 3×0.3 cm2 is selected, the system will work well in accidents with speed greater than 40 km/hr.