C/C热防护结构弹性波仿真分析方法及损伤对弹性波的影响

Elastic wave simulation analysis method and damage effect on elastic wave in C/C thermal protection structures

热防护结构(Thermal protection structures,TPS)作为可重复使用航天飞行器的关键结构,其安全性和可维护性至关重要。已有的针对可重复使用航天飞行器TPS的结构健康监测的研究不多,特别是C/C、C/SiC等复合材料制造的TPS。针对可重复使用航天飞行器C/C TPS,研究其基于主动弹性波的结构健康监测方法。提出了一种TPS弹性波数值仿真方法,在验证方法有效性的基础上,开展了面向C/C TPS损伤监测的弹性波传播特性研究,从信号时域特征、弹性波传播波场、损伤散射信号、损伤散射信号波场及损伤因子5个方面全面分析了弹性波在C/C TPS中的传播特性及损伤带来的影响。结果表明,当分层损伤边长大于25mm后,损伤因子剧烈变化,因此采用基于弹性波的结构健康监测方法可以很好地监测C/C TPS内部分层损伤及损伤的扩展情况。

Thermal protection structures(TPS)are key structures for reusable space vehicles,whose safety and maintainability are of vital importance.There are very few researches on structural health monitoring for TPS,especially for C/C,C/SiC composite TPS.The structural health monitoring method based on active elastic wave was studied for the C/C TPS of reusable space vehicles.A numerical simulation method of TPS elastic wave was proposed.On the basis of verifying the effectiveness of the method,the elastic wave propagation characteristics for C/C TPS structural damage monitoring were studied.From signal time domain characteristics,elastic wave propagation wave field,damage scattering signal,damage scattering signal wave field and damage index,analyzing the elastic wave propagation characteristics of C/C TPS and the effects of damage were analyzed completely.The results show that when the length of the stratified damage edge is greater than 25mm,the damage index changes dramatically,so the structural health monitoring method based on elastic wave can be used to monitor the internal stratified damage and damage expansion of C/C TPS.