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实验结果表明:高聚物在高应变率下的率相关的变形过程通常伴随着内部损伤的演化。这种演化导致了高聚物的最后断裂.采用改进了的熔丝网络模型及蒙特卡罗随机方法进行的数值模拟以及基于热激活机理所作的分析,得出了率相关的损伤演化律.相应地导出了计及损伤的率相关的非线性粘弹性本构关系,以考虑损伤弱化效应.进而提出了一个动态断裂判据,其同时与应变、应变率相关。采用SHPB技术与反向传播神经网络相结合的新方法,进一步证实了上述主要结果.
The experimental results show that the rate-dependent deformation of polymers at high strain rates is usually accompanied by the evolution of internal damage. This evolution led to the final rupture of the polymer.The rate-dependent damage evolution law was obtained using improved network models of fuses and Monte Carlo randomized numerical simulations and analyzes based on the mechanism of thermal activation A new nonlinear viscoelastic constitutive relation with damage-related rate is derived to consider the damage-weakening effect. Then a dynamic fracture criterion is proposed, which is related to both strain and strain rate. Using SHPB technology and backpropagation neural network combination of new methods to further confirm the above results.