On the ringing observed in shock-loaded piezoresistive stress gauges

It has been noted in several works that a gauge mounted close to a metal surface shows some electrical ringing when loaded rapidly by a shock wave. This effect may be explained in terms of the capacitance introduced between gauge and target. It was not expected that such effects would be observed when gauges are placed onto insulators such as ceramics. However, a similar trace was observed in which ringing at the top of the fast-rising elastic wave was seen. We present gauge data to illustrate this effect and show a simple solution to suppress this noise with an assessment of its limitations. High-speed photographs and fast emission measurements are used as an aid in explaining the phenomenon.