Search Results

Stochastic simulation is used to account for the variation in the manufacturing and assembling processes of the vehicle structure and occupant restraint system. An integrated full vehicle model with belted driver, 50th percentile male Hybrid III dummy, subjected to a 35 mph zero degree impact test, is used to present the scatter in the vehicle crash and occupant restraint performance. Yield stress of a typical mild steel has scatter values between 10 to 20% and a coefficient of variation of 5% is derived for scaling the stress and strain curve. The thickness tolerance has scatter values specified between 5 to 10% and a coefficient of variation of 2% is used in the study. The material properties and thickness of major structural components for absorbing impact energies, such as the motor/occupant compartment rails and upper rails, bumper beam, cradle, and toe pan are the random input variables for the structure.

There is a growing interest in using pressure sensors to sense side impacts, where the pressure change inside the door cavity is monitored and used to discriminate trigger and non-trigger incidents. In this paper, a pressure sensor simulation capability for side impact sensing calibration is presented. The ability to use simulations for side impact sensing calibration early in the vehicle program development process could reduce vehicle development cost and time. It could also help in evaluating sensor locations by studying the effects of targeted impact points and contents in the door cavity. There are two modeling methods available in LS-DYNA for predicting pressure change inside a cavity, namely airbag method and fluid structure interaction method. A suite of side impact calibration events of a study vehicle were simulated using these two methods. The simulated door cavity pressure time histories were then extracted to calibrate the side sensing system of the study vehicle.