固体火箭发动机药柱裂纹的J积分分析

Analysis of stability of crack in solid rocket motor grain with J-integral

为了探讨某固体火箭发动机药柱纵向裂纹在点火增压时的稳定性,采用三维粘弹性有限元法,在三维J积分圆柱围道曲面内裂纹尖端,构建奇异三维裂纹元,提高模拟精度,分别计算了随裂纹扩展所对应裂纹深度的J积分,并根据J积分随裂纹度变化规律,探讨裂纹的稳定性。研究表明,发动机点火发射时药柱前翼槽出现的纵向裂纹最为危险。

In order to investigate the stability of lognitudinal cracks in a solid rocket motor（SRM）grain during ignition pressurization,three-dimension viscoelastic finite element models of the motor with cracks were established.The three-dimension singular crack elements at the tips of cracks were developed to simulate the crack propagation.And all the singular crack elements were included in the 3-D J-integral loop surface to improve the calculational precision.Along with the crack propagation,the J-integral of the crack tips are respectively calculated to prejudge its stability.The results show that the most dangerous situation will occur in the fore slots with lognitudinal cracks during the rocket launch.