温度冲击下变截面圆孔装药的热力耦合分析

Thermal coupling analysis of variable cross-section circular hole grain under temperature impact

为研究温度冲击载荷对某改性双基推进剂装药结构完整性的影响,基于热力耦合基本理论,开展了不同温度下改性双基推进剂力学松弛试验,得到了不同温度下松弛模量的6阶Prony级数及以293.15 K为参考温度的时温等效W.L.F(Williams-Landel-Ferry)方程。利用Ansys有限元软件对由333.15 K降低至218.15 K的温度冲击条件下装药结构完整性进行分析,结果表明:装药的温度和应变在温度冲击前期变化较剧烈,至12 000 s时基本达到平衡,装药前端面两个拐角处在温度冲击前期发生破坏;为验证仿真计算结果,开展了由333.15 K降低至218.15 K的温度冲击试验。在温度冲击过程中,药柱沿轴向和径向出现裂纹,起裂点为推进剂装药前端两个拐角。温度冲击试验结果验证了仿真计算的准确性,说明该计算过程可用于装药结构完整性分析。

In order to study the influence of temperature impact load on the structure integrity of a modified double-base propellant grain, mechanical relaxation tests of the modified double-base propellant at different temperatures were carried out based on the basic theory of thermo-structure coupling. The sixth order Prony series of relaxation modulus at different temperatures and the time-temperature equivalent W.L.F(Williams-Landel-Ferry) equation with 293.15 K as the reference temperature were obtained. Ansys finite element method software was used to analyze the structure integrity of the grain under the temperature impact condition from 333.15 K to 218.15 K. The results showed that the temperature and strain of the grain changed sharply in the early stage of temperature impact, and basically reached balance at 12 000 s. Two corners of the grain front face were damaged in the early stage of temperature impact. In order to verify the simulation results, from 333.15 K to 218.15 K temperature impact test was carried out. The results showed that: in the process of temperature impact, the propellant column cracks appeared along the axial and radial directions, and the crack initiation points were at the front two corners of the propellant grain. The temperature impact test results verified the accuracy of the simulation calculation, which showed that the calculation process can be used to analyze the structural integrity of grain.