基于变形热的NEPE推进剂本构模型

针对硝酸酯增塑聚醚(NEPE)推进剂在冲击载荷下的变形生热现象,基于热传导理论,拟合得到了冲击载荷下的温升函数。基于固体推进剂力学特性所具有的温度相关性,将温升函数添加到黏-超弹本构模型中,由此提出了一种考虑变形生热的黏-超弹本构模型,利用NEPE推进剂的SHPB实验数据进行了参数的获取和模型验证。结果表明:该模型可以很好地预测固体推进剂在高应变率下的力学曲线; 在研究聚合物冲击载荷条件下本构模型时应考虑冲击生热对聚合物造成的软化影响。

Constitutive Model of NEPE Propellant Based on Deformation Heat

Aiming at the deformation heat phenomenon of nitrate ester plasticized polyether(NEPE)propellant under impact load,the temperature rise function under impact load was obtained based on the heat conduction theory. Due to the problem that the mechanical properties of solid propellants is temperature-dependent,a new viscous-hyperelastic constitutive model considering deformation heat was proposed. The split hopkinson pressure bar(SHPB)tests of NEPE propellant were used to obtain parameters and verify the constitutive model. The result shows that the proposed model can predict the true stress-engineering strain curve well under high strain-rates,and the softening effect of heat caused by impact load on the polymer should be considered while studying the constitutive model of polymer under impact load.