Erlangen 2018 – scientific programme

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AGA: Arbeitsgruppe Physik und Abrüstung

AGA 2: Verification and Conventional Systems

AGA 2.1: Talk

Wednesday, March 7, 2018, 16:30–17:00, B 0.014

Seismic Modelling of Tracked-Vehicle Signals for Monitoring and Verification — •Mathias Pilch and Jürgen Altmann — Experimentelle Physik III, TU Dortmund

To understand the characteristics of seismic signals measured with passes of tracked vehicles we numerically modelled the responses of a layered soil at various distances to a vertical force pulse. The soil properties were chosen similar to the ones found at the measurement site. The pulse amplitude and shape followed the force time function measured under the track elements. Because of different wave types and of reflection at the layer boundaries, the signal shape varies with distance. During a vehicle pass the road wheels roll over the tracks (with different left-right offset), each producing one force pulse at each element. At a sensor site the one-pulse signals for the corresponding slant distances are superposed, shifted by the respective excitation times. As the vehicle moves, the times and distances vary. The sum signals and their spectra show qualitative agreement with the ones from the measurements. Differences are: the theoretical signals are much simpler and weaker, and higher frequencies seem to be damped much less at larger distance. Due to the large variability seismic vehicle-type recognition seems much more difficult than acoustic.