Evaluation of accelerometer mechanical filters on submerged cylinders nearan underwater explosion

An accelerometer, mounted to a structure near an explosion to measure elast o-plastic deformation, can be excited at its resonant frequency by impulsiv e stresses transmitted within the structure. This results in spurious high peak acceleration levels that can be much higher than acceleration levels f rom the explosion itself. The spurious signals also have higher frequencies than the underlying signal from the explosion and can be removed by a low pass filter. This report assesses the performance of four accelerometer and filter assemblies. The assessment involves measurements of the response of a mild steel cylinder to an underwater explosion, in which each assembly i s mounted onto the interior surface of the cylinder. Three assemblies utili se a piezoresistive accelerometer in which isolation is provided mechanical ly. In the fourth assembly, a piezoelectric accelerometer, with a built-in filter, incorporates both mechanical and electronic filtering. This assembl y is found to be more suitable because of its secure mounting arrangement, ease of use, robustness and noise free results.