基于损伤型本构高过载下装药强度数值仿真方法研究

Research on Numerical Simulation Method of Grain Strength Based on Damage Constitutive Model under High Overload

关键词:  高过载  非线性粘弹性  累积损伤  强度  固体推进剂

Key words:  High overload  Nonlinear viscoelastic  Accumulative damage  Strength  Solid propellant

摘要:

为了准确反映改性双基推进剂装药在高过载发射条件下的破坏情况，采用基于含累积损伤的非线性粘弹性本构模型，利用ABAQUS有限元软件二次开发的UMAT子程序，对某型火箭弹在过载发射情况下的装药进行了数值研究，分析了装药在高过载条件下的变形行为和力学特性。结果显示，在最大加速度为1.39×10 4 g 的高过载下，最大应力发生在装药底部内孔处；装药径向尺寸变化很小，可以忽略发动机壳体对装药外表面的约束而将其视为自由表面。比较了最大应力强度准则和累积损伤准则对装药在加速度冲击和压强端面冲击载荷下破坏的判断，两种判据的结果都表明，装药在高过载冲击载荷下没有被破坏。

Abstract:

In order to make accurate analysis of the grain integrity of modified double-based propellant，the numerical simulation using the secondary developed UMAT subroutine of the ABAQUS finite element software of a certain type of rocket under high overload were completed based on accumulative damage nonlinear viscoelastic constitutive model. The deformation and mechanical behavior of the grain were analyzed. The results show that the maximum stress take place in the inner circle of grain bottom under high acceleration overload with the maximum value is 1.39×10 4 g .Considering that the radial deformation of grain is too small，the constraint to grain outside surface imposed by case of solid rocket motor can be ignored and thus the grain outside surface can be taken as a free surface. Two different kinds of strength criterions were compared to judge the solid rocket propellant grain integrity under the acceleration impact load and the end face pressure impact load. The Maximum stress strength criterion as well as the strength criterion based on accumulative damage both suggest that the grain should not be destroyed.