Pyroshock Response Prediction of Spacecraft Structure in Wide Frequency Domain Based on Acceleration FRF

Xiong Wang,Yongbing Dang,Jifeng Ding,Yi Sun,Wei Liu

doi:10.3390/aerospace9020054

Abstract

The initiating explosive shock environment of an aerospace mission has the characteristics of instantaneity, high amplitude and a wide frequency domain. An improved method based on the acceleration frequency response function (FRF) and virtual mode synthesis method (VMSS) is proposed to predict the pyroshock response of a spacecraft structure in a wide frequency domain. Firstly, the statistical energy analysis (SEA) model of the spacecraft structure was established, and the FRF and modal density of the model were obtained. Then, the paper explains how, due to the small number of modes in the low-frequency band, the calculation results of the SEA method in the low-frequency band were not accurate enough. The FRF of the SEA model in the low-frequency band was modified by an FRF test of the structure. Finally, the shock response spectrum (SRS) was obtained based on the VMSS and the modified FRF. A shock experiment on the spacecraft structure was conducted by using the shock experiment system, which is based on a light-gas gun. The accurate shock force function and acceleration response results were obtained. The numerical results based on the improved method are in line with those in the experiment. This verifies that the novel method can better grasp the response characteristics of the structure in the broadband domain. The novel method effectively improves the response prediction accuracy of the SEA model in the relatively low-frequency band. While ensuring the computational efficiency, more accurate shock response results in a wide frequency domain were obtained. The novel method presented in this paper provides support of numerical analysis for pyroshock response prediction of spacecraft structure in a wide frequency domain.

Highlights

A pyrotechnic separation device is commonly used in the launch, on-orbit and return of spacecrafts
The novel method presented in this paper can better grasp the response characteristics of the structure in the broadband domain and effectively improves the response prediction accuracy of the statistical energy analysis (SEA) model in the relatively low-frequency band
This study presents an improved method of predicting the pyroshock response of a spacecraft structure in a wide frequency domain based on acceleration frequency response function (FRF) and the virtual mode synthesis method (VMSS) method

Summary

Introduction

A pyrotechnic separation device is commonly used in the launch, on-orbit and return of spacecrafts. The key point of the shock response prediction method based on the VMSS and SEA models is the accurate FRF of its structure Considering this background, this paper studies the pyroshock response prediction method of spacecraft structures in a wide frequency domain through experimental and theoretical methods. The novel method presented in this paper can better grasp the response characteristics of the structure in the broadband domain and effectively improves the response prediction accuracy of the SEA model in the relatively low-frequency band. It provides the support of numerical analysis for pyroshock response prediction of the spacecraft structure in a wide frequency domain

Derivation of the Basic Theory

Shock Experiment and Simulation Study of Spacecraft Structure

SEA Model and FRF

Conclusions