Wave propagation characteristics and broadband dynamic response prediction of aerospace structure under pyroshock load

Abstract

In this work, the propagation characteristics of near-field and far-field waves in a honeycomb sandwich structure subjected to pyroshock are analyzed using the wave finite element method, and the mode numbers of flexural and longitudinal waves are obtained based on the phase closure principle of standing waves. By superimposing propagating waves, a broadband dynamic response prediction method is proposed for honeycomb sandwich structures and validated against the analytical solution of an Euler beam and the conventional three-dimensional FEM results of a honeycomb sandwich structure. The influence of structural parameters on flexural and longitudinal waves is investigated, along with their effects on the broadband response. The results reveal that increasing face sheet thickness affects near-field and far-field waves in the same direction, reducing the broadband modal density of bending waves by 19% and slightly decreasing that of longitudinal waves. In contrast, increasing core layer height affects near-field and far-field waves in opposite directions: it reduces the broadband modal density of near-field bending waves by 30.3% while slightly increasing that of far-field longitudinal waves. Adjusting the core layer height can significantly reduce the frequency-domain peak acceleration and broadband energy by 54.1% and 52.7%, respectively.