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为了探讨环境温度对固体火箭发动机点火发射时药柱内表面裂纹稳定性的影响,以翼锥-过渡伞盘-圆柱组合药型的发动机为例,采用三维有限元方法,在发动机药柱的危险截面上沿危险方向预设裂纹,在裂纹尖端构建奇异三维裂纹元,计算在不同环境温度下点火发射时裂纹的应力强度因子。结果表明,药柱表面裂纹在伞盘顶端和圆柱段表面不会以张开方式扩展,伞盘顶端裂纹不会以滑开方式扩展,圆柱中段表面裂纹除低温外,在高温和常温点火发射时均自动止裂;伞盘裂纹若扩展将以撕开方式失稳扩展,低温较高温点火发射危险,圆柱中段表面裂纹可能以撕开方式扩展,高温较低温更为危险。
In order to study the influence of ambient temperature on the crack internal stability of solid propellant rocket engine, a three-dimensional finite element method was used to take the propeller-transitional umbrella disc-cylinder combination type engine as an example. The crack is pre-set along the dangerous direction in the cross-section and the singular three-dimensional crack element is constructed at the tip of the crack. The stress intensity factor of the crack at different ambient temperatures is calculated. The results show that the crack on the surface of the column does not expand in an open manner at the top of the column and the surface of the cylindrical section. The crack at the top of the column does not expand by sliding. In addition to the low temperature, All will automatically crack. If the crack of the umbrella plate is expanded, it will be unstably expanded by the tearing method, and the ignition at a relatively low temperature is dangerous. The surface cracks in the middle part of the cylinder may be expanded by tearing, and the higher temperature and the lower temperature are more dangerous.