固体发动机药柱的裂纹稳定性分析

Stability analysis of the crack in solid rocket motor grain

关键词:  固体推进剂火箭发动机  推进剂药柱  裂纹扩展  有限元法  应力强度因子

Key words:  Solid propellant engine  Propellant grain  Crack propagation  Finite element method  Stress intensity factor

摘要:

为了确定固体发动机药柱内表面裂纹在内压与轴向过载联合作用下的稳定性及最大允许裂纹深度 ,以翼锥药形的固体发动机为例 ,在危险截面上沿危险方向预设裂纹 ,采用有限元方法 ,于裂纹尖端构建奇异二维裂纹元 ,模拟裂纹扩展 ,分别计算随着裂纹扩展所对应裂纹深度的应力强度因子 ,由此判断在内压与轴向过载作用下 ,裂纹只能以滑开方式失稳 ,最大允许裂纹深度可由临界应力强设因子确定

Abstract:

A method to analyze the grain crack stability was presented The most dangerous section and the more dangerous points were determined by the three dimension viscoelastic finite element analysis of solid rocket motor grain Several cracks were preset along some directions in the more dangerous points, and the crack was simplified as the two dimension elastic crack because the most dangerous section is at the middle of the grain and motor work time is rather short The singular crack element and two dimension elastic finite element method were used to calculate the crack stress intensity factor The grain crack stability was discussed by stress intensity factor