Shock spectrum measurement and analysis of underwater explosion on a floating shock platform

The time domain curve of a moving body is directly perceivable, but the motive characteristics of the body can be shown further by using the frequency domain analysis. Although the shock spectrum analysis is a useful method of frequency domain analysis to study the shock motion, the zero drift phenomenon of shock acceleration measurement influences the accuracy of shock spectrum data. In the tests of underwater explosion on a floating shock platform, we have obtained the accurate shock spectrum by using a method of verifying each other between the calculated shock spectrum from acceleration and the measured shock spectrum from reed gauge. Our analysis has shown the shock spectrum is used not only to estimate the shock response of the ship equipment, but also to identify three different frequency regions in the shock spectrum, which are corresponding to the three processes induced by underwater explosion, that is, shock, afterflow and bubble pulse, respectively. And hence, we have found that the afterflow of underwater explosion is important to shock and vibration of ship equipment.