Current crash sensing systems are normally based on acceleration sensing. Therefore, the deceleration pulses affecting the car’s body are used to apply the firing thresholds of the restraint systems. A new kind of crash sensing consists of measuring high frequent chassis vibration regarding frequencies up to 20 kHz:​ crash sensing based on structure-borne sound (SBS). The main benefit of this technology will be to support the common deceleration-based crash detection in crash type distinction during the early crash phase. To be able to use the acquired data in a physically reasonable way, the events causing SBS during crash important to know.

In the proceeding of the study, the events occurring during a crash are interpreted as shock excitations of different impulse lengths that can be divided into hard and soft events. Valuable results from a multitude of component crash tests on a drop tower test stand are transferred to vehicle crashes in serial development. The applicability of crash separation criteria is examined. The crash type distinction of hard/soft crashes based on structural vibration sensing is the main idea to support the differentiation of hard no fire tests and soft must fire tests. The study shows that shock excitation of the vehicle structure is the most important cause of high frequent vibration signals acquired during vehicle crashes.

The article deals with the usage of high frequent structural vibration in the range up to 20 kHz for crash detection. The understanding of the vehicle being a structure under linear elastic shock excitation leads to a physically plausible usage of the signals for crash type distinction.