关键词: 推进剂药柱;表面裂纹;推进剂燃烧;缺陷分析

Abstract: Associated with the characteristic of stress distribution in the high loaded solid propellant grain under combusting condition, two types of cracks on its cavity surface, the transverse surface crack and the longitudinal surface cracks,are taken into accounted. Respectively, one brick shaped experimental grain and another disc shaped one are employed for simulating above two types of cracks.Through numerical approach by FEM, the Squeezing Propagation Mode (SPM) is concluded to be rational for describing single surface crack propagation of combusting grain. In detail, this model is denoted by an empirical formula, which illustrates effects on transverse tearing stress of the surface crack tip due to three factors, such as pressure of combusting gases on main burning surface, pressure of gases in the gap of surface crack, and deepness of surface crack. According to this model, the longitudinal surface crack is found easier to propagate than the transverse surface crack

Key words: Propellant grain;Propellant combustion;Surface cracking;Defect analysis