低温环境下固体火箭发动机药柱伞盘结构设计

Design for the umbrella slot configuration of the solid rocket motor grain under low temperature condition

关键词:  固体推进剂火箭发动机  粘弹性  有限元法  药型结构设计+

Key words:  Solid propellant rocket engine  Viscoelasticity  Finite element method  Design grain configuration~+

摘要:

为提高固体火箭发动机伞盘药型药柱的低温力学性能,可通过调整伞盘药型来缓解其应力应变集中水平。以某固体火箭发动机药柱前伞盘为例,应用三维粘弹性有限元分析方法,分析不同前伞盘药型结构发动机的低温应变场,得到药柱前伞盘最大VonMises应变随伞盘药型结构变化的规律,结果表明药柱伞盘宽度的变化对伞盘顶部应力应变集中的影响最大。再综合考虑内弹道性能和浇铸工艺的要求可确定药柱前伞盘的最佳结构。该方法可为固体火箭发动机药型设计提供定量参考。

Abstract:

The low temperature mechanic property of the solid rocket motor is one of the most important qualitative criteria. Under low temperature loading, the serious stress and strain concentrations always occur at the top of the umbrella slot and can cause cracks in the concentrative position. The width and depth of the umbrella slot can be adjusted to release the stress and strain concentration in order to improve the mechanic property. With three-dimension viscoelastic finite element method, several finite element models of the motor grain with different width and different depth of fore umbrella slot were established. Under low temperature loading, the Von Mises strain fields of the grain were studied.The Von Mises strain fields of fore umbrella slot were obtained. The results show that the maximum Von Mises strain of the umbrella slot descends significantly with the increment of its width.Thus, adjusting the width of the umbrella slot is more useful than adjusting its depth. Then the suitable configuration of the umbrella slot can be obtained by synthesizing the demand of internal ballistic trajectory and produce technics. The analytical method and these conclusions are available for designing solid rocket motor grain configuration.