The application of pressure cure molding technology can effectively reduce the structural integrity problems of casting solid rocket motors. In order to describe the curing and cooling process under this new technology more realistically, it is decomposed into two processes, pressurization curing, and pressure relief cooling and a time-varying segmented solid propellant intrinsic equation applicable to the pressure cure molding technology is proposed. The constitutive equation takes into account the change in material properties caused by the change in the state of the propellant during the curing process. In order to accurately model the changes in mechanical properties of the propellant during curing, the present constitutive equations for this process are rewritten in incremental form and implemented in the user subroutine UMAT of the finite element analysis platform ABAQUS. The detailed derivation steps of the constitutive equation are introduced in this paper, and the subsequent application analysis is carried out with reference to the star-shaped grain. The final stress and strain state of the propellant after cooling is used as the main analytical index. The results show that the pressure cure molding technology can effectively reduce the residual stress and the residual strain on the inner surface of the propellant grain. The pressure cure effect on the outer surface of the grain is relatively small compared to the overall reduction. The time-varying constitutive model provides technical support for a more accurate description of the pressure cure process.

中文翻译：

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压力固化推进剂的粘弹性本构模型

压力固化成型技术的应用可以有效减少铸造固体火箭发动机的结构完整性问题。为了更真实地描述该新技术下的固化冷却过程，将其分解为加压固化和减压冷却两个过程，提出了适用于压力固化成型技术的时变分段固体推进剂内禀方程。本构方程考虑了在固化过程中推进剂状态变化引起的材料特性变化。为了准确模拟固化过程中推进剂机械性能的变化，该过程的本构方程以增量形式重写，并在有限元分析平台 ABAQUS 的用户子程序 UMAT 中实现。本文介绍了本构方程的详细推导步骤，并结合星形晶粒进行了后续的应用分析。冷却后推进剂的最终应力应变状态作为主要的分析指标。结果表明，压力固化成型技术可以有效降低推进剂药柱内表面的残余应力和残余应变。与整体减少量相比，颗粒外表面的压力固化效果相对较小。