长期贮存的固体发动机药柱脱粘界面裂纹分析

Analysis of the Interfacial Crack in Debonded Layer of Long Term Storage Solid Motor Grain

为了分析长期贮存的固体导弹发动机药柱脱粘层界面裂纹在燃气内压和轴向过载联合作用下的扩展情况,建立了发动机药柱在包覆层与推进剂之间脱粘的三维有限元计算模型,并于脱粘界面的裂纹尖端设置三维奇异裂纹元,模拟脱粘界面裂纹扩展。在包覆层与推进剂之间设置不同深度脱粘,计算了在燃气内压和轴向过载联合作用下不同贮存期、不同深度的界面裂纹尖端的应力强度因子,得到了界面裂纹应力强度因子随贮存时间、脱粘深度的变化规律,对长期贮存的固体发动机脱粘界面裂纹的扩展进行了分析。

The interfacial debonded cracks are liable to occur in the stress relief boot of solid missile motor. In order to determine the allowable debonded depth in different storage period, a method to analyze the stability of the inteffacial crack is presented. Under the circumstance of internal pressure and axial acceleration loading, the three-dimension finite element models of the motor grain with interfacial debonded cracks were established, and several interfacial debonded cracks were preset along the stress relief boot between cladding and propeUant. Thus three-dimension singular crack elements at the tips of fore and rear stress relief boot were established to simulate the debond propagation. Along with the interracial debended crack propagation, the stress intensity factors of the crack tips in different storage period were respectively calculated to prejudge its stability. The method and conclusions will be helpful in using solid missile motor with interfacial debonded cracks.