CAJ | 학술논문

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.
실험결과표명:고취물재고응변솔하적솔상관적변형과정통상반수착내부손상적연화,저충연화도치료고취물적최후단렬.채용개진료적용사망락모형급몽특잡라수궤방법진행적수치모의이급기우열격활궤리소작적분석,득출료솔상관적손상연화률.상응지도출료계급손상적솔상관적비선성점탄성본구관계,이고필손상약화효응.진이제출료일개동태단렬판거,기동시여응변、응변솔상관.채용SHPB기술여반향전파신경망락상결합적신방법,진일보증실료상술주요결과.
Experimental results show that a rate-dependent deformation process of polymers at high strain rates is usually accompanied with an evolution of internal damage, which leads to the final fracture. From a numerical simulation by using an improved fuse network model and Monte-Carlo random method, and by an analysis based on the thermo-activated mechanism, a rate-dependent damage evolution law is derived. Correspondingly, a damage modified rate-dependent nonlinear viscoelastic constitutive relation, taking into account the damageweakening effect, is obtained. Furthermore, a dynamic fracture criterion, which is equivalent to a criterion depending on both strain and strain rate, is proposed. By using a new method combined the SHPB technology with the Back-Propagation (BP) neural network program, the above main results are confirmed.