Improvements are needed in crash severity discrimination for multi-staged airbags, side airbags, seat belt pretensioners, and related occupant restraint devices. In a three-stage cooperative research project Advanced Safety Concepts Inc. (ASCI) has been investigating the use of shock waves generated during a crash to provide substantially earlier indication of the direction and severity of crash. A piezoelectric shock sensor for location on the windshield glass has been developed. With the piezoelectric sensors, crash severity can be assessed as a function of energy (proportional to velocity-square) rather than force (proportional to acceleration). In stage 1 of the project, ASCI instrumented a vehicle windshield with piezoceramic sensors used to detect early signs of stress failure for industrial applications such as storage tanks. In stage 2, ASCI developed a piezoelectric sensor for automotive applications. The ASCI piezoelectric sensors are adhered to the inside glass surface. In stage 3, the ASCI windshield mounted piezoelectric crash sensing system was then subjected to industry-standard crash tests. Analysis of the data indicated that two modes of crash-induced vibration are detected by the ASCI piezoelectric sensors located on the windshield. Transverse or flexural waves, similar to the waveforms detected by standard accelerometers, are detected in the lower frequency range; and longitudinal or in-plane stress-waves are detected in the higher frequency range. By comparing the two frequencies, information is obtained which discriminates a non-crash event from a crash event. In conclusion, ASCI piezoelectric sensors mounted on the windshield represent a promising new approach to crash sensing and crash discrimination.
Crash sensing using piezoelectric sensors on vehicle windshields
Crash-Sensierung mit Hilfe piezoelektrischer Sensoren auf der Windschutzscheibe
6 Seiten, 3 Bilder
Conference paper
English
Airbag , Aufprallversuch , Biegeschwingung , Energie , Frequenzbereich , Glas , mechanische Schwingung , Personenkraftwagen , piezoelektrischer Aufnehmer , Sicherheitseinrichtung (Fahrzeuginsasse) , Sicherheitsgurt , Sicherheitssystem , Transversalwelle , Verkehrsunfall , Wellenform , Wellenformanalyse , Windschutzscheibe
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