Evolution of temporal features during pyroshock propagation caused by wave dispersion

Abstract

Aerospace devices are vulnerable to pyroshock and require testing. The shock response spectrum (SRS) compares shock severity but ignores temporal features. To improve testing reliability, temporal characteristics and their changes during pyroshock propagation need to be studied. In this paper, the shock propagation problem is studied experimentally. Two temporal features, i.e., the effective duration and the initial rise time, are characterized by the moving mean square method. An appropriate window length is suggested based on the frequency analysis of the shock environment. The evolutions of the effective duration and the initial rise time are characterized and traced during shock propagation. The elastic wave mode of shock propagation is analyzed. It is found that shock propagates in structures mainly in the form of flexural mode. A temporal features prediction method based on traveling damped sine waves is also provided and validated by experimental results.