固体发动机药柱表面裂纹的处理

工程实际中通常采用于药柱表面裂纹处铲槽的方法来释放裂纹尖端的应力应变集中,以确保药柱含裂纹的固体发动机能正常点火发射.为确定铲槽的深度和宽度,基于线粘弹性三维有限元,首先确定发动机药柱点火发射时的危险部位;其次,在危险部位设置深度不同的裂纹,在裂纹尖端构建三维奇异裂纹元,模拟裂纹扩展,分别计算随着裂纹扩展所对应裂纹深度的各类应力强度因子,由此判断裂纹的稳定性,以确定是否需要对裂纹进行铲槽处理;最后,确定在危险裂纹处需要铲槽的深度与宽度.通过对某翼锥-圆柱组合型药柱在点火发射时的数值分析,提出了药柱危险部位裂纹的处理方法,量化了药柱表面裂纹的处理.该方法可为修复药柱表面含缺陷的发动机提供参考.

Treatment of surface crack on solid motor grain

In order to ensure solid motor with cracked grain to be successfully launched, the strain and stress concentration at the tips of crack should be released by shoveling slot on the crack of grain surface. Based on linear visco-elasticity 3D finite element method, the depth and breadth of slot can be determined. Firstly,dangerous locations of motor at launch are defined. Secondly, 3D singular crack elements at the tips of crack are established to simulate the crack propagation. Along with the surface crack propagation, the stress intensity factors of the crack tips are respectively calculated to prejudge its stability. Finally, the depth and breadth of slot are obtained. Through numerical analysis for some cone-cylinder combined grain at launch, the treatment method for cracks at dangerous locations was put forward. The method and conclusion can provide a reference for repairing solid rocket motor with surface defects.