Transient Ray Tracing Method for High Frequency Bending Waves in Complex Structures

High frequency transient wave propagation is a very interesting physical area. Currently, a large number of measurement methods are in use to qualify these signals. Typically, however, only the corresponding frequency domain spectra are computed and further investigated. Concerning the simulation of these signals there have been many attempts to approach real test signals. In many cases, however, it was only possible to calculate averaged spectra or low frequency time signals with an acceptable effort. In case of the application of crash impact sound sensing there is a need for simulating a high-frequency transient bending wave in the range from 5 to 20 kHz in the time domain. Thus, a simulation method based on the mathematical description of the main physical effects is developed (section 2). These formulas describe the wave propagation on its way through the structure. In order to get a good reproduction of propagation the infinite number of possible rays has to be reduced to only a few relevant rays (section 3). Here, the superposition of the single rays to the final time signal at the sensor position is also shown. In a further step the application of the simulation method for a typical car structure is shown and the good agreement between measurement and simulation is discussed (section 4). A short outlook on possible application areas (section 5) is followed by the conclusion (section 6).