固体推进剂药柱不确定结构分析及方法比较

针对复合固体推进剂力学性能参数的不确定性对固体火箭发动机药柱结构分析的影响,使用软件ANSYS parametric design language(APDL)建立了受固化降温载荷和压力载荷联合作用下药柱结构的参数化有限元模型.在此基础上,分别应用蒙特卡洛法和响应面法,研究了复合固体推进剂热膨胀系数与初始泊松比的随机分布对药柱结构有限元分析的影响,并对两种方法得到的概率分析结果进行了对比.结果表明:复合推进剂热膨胀系数和初始泊松比微小的变化会对结构分析结果产生较大的影响；药柱结构响应对初始泊松比更为敏感.在药柱结构有限元分析时考虑推进剂力学性能参数的不确定性十分必要.通过对两种不确定结构分析方法的比较发现,响应面法得到的分析结果与蒙特卡洛法得到的分析结果十分接近,且分析效率远高于蒙特卡洛法.

Uncertain structural analysis of solid propellant grain and comparison of the methods

Concerning the influence of uncertainty in composite solid propellant's mechanical properties on structural analysis of solid rocket motor(SRM) grain,the parameterized finite element model of SRM grain under temperature and pressure loading is constructed through ANSYS parametric design language (APDL).On that basis,the influence of random distribution of composite solid propellant's thermal expansion coefficient and initial Poisson's ratio on finite element structural analysis of SRM grain is studied with Monte-Carlo method and response surface method.Results of the two different methods are compared.The results show that small changes in composite solid propellant's thermal expansion coefficient and initial Poisson's ratio cause relatively great influence on the results of structural analysis and the structural responses of the propellant grain are more sensitive to initial Poisson's ratio.So,uncertainty in composite solid propellant's mechanical properties should be considered during finite element structural analysis of SRM grain.It is indicated by the comparison of this two kinds of methods that response surface method can give approximately the same results as those from Monte-Carlo method and is greatly more efficient than Monte-Carlo method.