极端条件下大长径比固体发动机药柱结构完整性快速分析

Rapid Structural Integrity Analysis of the Solid Propellant Grain with Large Aspect Ratio under Extreme Conditions

药柱的结构完整性对固体火箭发动机正常工作具有重要意义,大长径比、高马赫数、复杂药形和极端温度等给药柱结构完整性带来了严峻的考验。基于ANSYS Workbench软件平台,采用粘弹性分析方法针对某大长径比(L/D>16)翼柱形药柱进行了结构完整性分析,得到了极端温度条件下点火增压过程药柱的应力-应变响应,为药柱的完整性评估提供指导。同时为实现点火增压过程中药柱结构完整性快速分析,建立了药柱内关键位置药柱应力-应变响应的快速评估方法,开发了结构完整性快速评估程序,并应用该评估系统分别对高温(60℃)和低温(-40℃)点火增压过程中药柱结构完整性进行分析,得到药柱内危险位置的等效应力、等效应变和等效模量的变化情况,最后与基于线粘弹性本构模型的有限元仿真结果进行了对比分析。仿真结果表明,两种计算方法得到的药柱内危险位置的等效应力、等效应变和等效模量大小基本吻合,且快速评估系统大大节省了计算时间,可实现点火增压过程复杂药形内孔燃烧药柱的快速分析。

The structural integrity of the solid propellant grain is of great significance to the correct working of the solid rocket motor(SRM).Large aspect ratio,high Mach,complex grain shape and extreme temperature have brought severe challenges to the structural integrity of grains.In this paper,based on ANSYS Workbench software platform,the structural integrity of the finocyl grain with a large aspect ratio(L/D>16)is analyzed by mean of viscoelastic theory.The stress-strain response of the grain subjected to the ignition pressurization loading at extreme temperature is obtained,which provides guidance for the integrity evaluation of the grain.At the same time,in order to realize the rapid analysis of the structural integrity,the new calculating method of the stress-strain response at the key position in the grain established,and a rapid evaluation program is developed.Then the structural integrity of the grain during the high temperature(60℃)and low temperature(-40℃)is analyzed by using the rapid evaluation program,and the results of the equivalent stress,strain and modulus of the key points of the grain are obtained.Finally,by comparing with the finite element simulation results based on the linear viscoelastic constitutive model,the results obtained by two methods are basically consistent.The rapid evaluation program greatly saves the calculation time and shows the good applicability on the structural integrity analysis for the finocyl grain.