温度载荷下带筋套管形装药结构完整性分析

Structural integrity analysis for the canular solid propellant grains subjected to temperature loading

关键词:  固体推进剂火箭发动机  结构完整性  热粘弹性  热膨胀系数  肉厚系数

Key words:  Solid propellant rocket engine  Structural integrity  Thermoviscoelasticity  Thermal expansion coefficient  Thickness coefficient

摘要:

为了分析带筋套管形装药在低温多次出现点火爆炸的原因,基于Updated Lagrangian方法,推导了热粘弹性大变形增量本构关系。在分析瞬态温度场的基础上,进一步给出了热应力应变分布,指出了危险点位置。通过选取十二种热膨胀系数以及十四种肉厚系数,对推进剂药柱进行了结构完整性计算,得出热膨胀系数与最大等效应力应变成线性关系,而肉厚系数与最大等效应力应变之间成指数函数关系的结论。结果说明:肉厚系数的选择对固体火箭发动机装药保持结构完整性有重要影响。

Abstract:

For test-firing failure evaluation of the canular solid propellant grains under low temperature surrounding,the thermoviscoelastic large deformation incremental constitutive equation was derived based on Updated Lagrangian method.In order to investigate the transient temperature field and the distribution of thermal stress and strain,a step-by-step finite element model accompanied by concepts of time-temperature shift principle and thermorheologically simple material assumption was used.In addition,the dangerous location was obtained from the simulation.Twelve different thermal expansion coefficients and fourteen thickness coefficients were assumed to evaluate the effects on the structural integrity.The results show that thermal expansion coefficient has a linear relation to the maximum equivalent stress and strain response,whereas thickness coefficient has an exponential relation to them,which show that thickness coefficient plays an important role in structural integrity of solid propellant grains.