This paper describes the application of piezoelectric shock sensors located on a car windshield to provide crash severity information at an early stage in an impact. Three sensors are used on the inside of the glass, one at the centre front lower edge, the other two at each of the upper corners. In static tests, the sensors demonstrated excellent repeatability. In industry-standard crash tests both piezoelectric sensors and accelerometers were installed: the sensors detected significant crash energy earlier than the accelerometers detected change in velocity. Analysis of the sensor data showed that two modes of crash-induced vibration are detected: transverse or flexural waves; and longitudinal or in-plane stress waves. Comparison of these frequencies discriminates a non-crash event from a crash event. Further testing is planned to develop an algorithm that can be used to improve occupant restraint systems. For the covering abstract see ITRD E126782.
Samenvatting