热防护系统单自由度动态特性理论模型

Single degree of freedom dynamic theoretical model for a thermal protection system

针对防热瓦的加速度响应以及应变隔离垫(SIP)的动强度问题,提出了热防护系统(TPS)随机振动单自由度动态特性理论模型,并且考虑了SIP的线性刚度和非线性刚度;推导了线性理论模型的解,并且研究了非线性理论模型的迭代求解流程;将有限元分析结果与线性理论解进行了对比,验证了线性理论模型的合理性。对比了非线性理论模型与线性理论模型的解,结果表明:SIP非线性刚度对动态响应具有重要影响,且SIP等效线性刚度系数与激励的类型有关;研究了外载荷大小对非线性理论模型的等效线性刚度系数和系统响应的影响规律,结果表明载荷大小的增加会导致系统等效线性刚度的增加,并且响应也随之提高。该研究为防热瓦的加速度响应、SIP的动强度和TPS动态完整性分析提供了理论依据。

A single degree of freedom random dynamic theoretical model for a thermal protection system(TPS)was proposed to study the acceleration response of the tile and dynamic strength of the strain isolation pad(SIP).The linear and nonlinear stiffnesses of the SIP were considered.The solutions of the linear theoretical model were derived,and the iterative solving procedure of the nonlinear theoretical model were studied.The rationality of the linear theoretical model was verified by comparing linear theoretical solutions with the results of finite element analysis.The solutions of nonlinear and linear theoretical models were compared.It is shown the dynamic responses and the equivalent linear stiffness coefficient are related to the nonlinear stiffness of SIP and the type of excitations.The influences of external loads on the equivalent linear stiffness coefficient and the responses were studied.The equivalent linear stiffness and the responses increase with the increasing of external loads.The investigations provide a theoretical basis for the analyses of the acceleration response of the tile,dynamic strength of the SIP and dynamic integrity of the TPS.