Development of CAE-Based Crash Sensing Algorithm and System Calibration

State of the art electronic restraint systems rely on the acceleration measured during a vehicle crash for deployment decisions. The acceleration signal is analyzed with different criteria, among which the velocity change is a dominant criterion in almost any existing crash detection algorithm. Sensors in the front crush zone have recently been added to help develop restraint systems that comply with the new FMVSS208 and EuroNCAP regulations. Front crash sensors are usually evaluated for their velocity change during a crash and typically play a key role in the deployment decision. CAE based FEA analysis has recently been used to generate signals at the sensor module locations in crash simulations to provide supplemental information for crash sensing algorithm development and calibration. This paper presents an initial effort in developing a velocity-based crash detection algorithm, that allows broad use of CAE generated velocity time histories for system calibration. Sample calibrations for a FMVSS 208 and EuroNCAP compatible dual stage airbag system are shown based on data obtained from testing and simulation of production vehicles. Deployment times established using the velocity-based algorithm are comparable with those determined from a traditional acceleration-based algorithm. It is further shown that CAE analysis provides acceleration data, which give the same system response as real vehicle data when evaluated with appropriate algorithms.