Our previous study observed a non-monotonic time-dependent deformation from the long-term isothermal tensile creep tests, indicating the significant influence of physical aging on viscoelastic behavior. In this work, a new physical mechanism-based thermo-rheological complex constitutive relation that combines Ngai’s coupling model and Schapery’s nonlinear viscoelastic framework is established. A piecewise function was used to represent the non-monotonic time-varying compliance, in which molecular cooperativity and the interaction between different relaxing units were considered. The strength of the interaction is presented by a coupling strength parameter. The effects of stress and temperature on the deformation are represented by not only two shift factors but also are associated with the coupling strength parameter, which is modeled as a function of the fictive temperature. The physical aging effect is also incorporated into the evolution of the fictive temperature. The proposed model was verified by a comparison of the experimental and finite element simulated results. Finally, the physical meanings of the model parameters and their correlation with the macroscopic deformation of the laminates were discussed.

我们之前的研究在长期等温拉伸蠕变测试中观察到非单调的时间依赖性变形，表明物理老化对粘弹性行为的显着影响。在这项工作中，建立了一种新的基于物理机制的热流变复杂本构关系，该关系结合了Ngai的耦合模型和Schapery的非线性粘弹性框架。采用分段函数来表示非单调时变顺应性，其中考虑了分子协同性和不同松弛单元之间的相互作用。相互作用的强度由耦合强度参数表示。应力和温度对变形的影响不仅由两个位移因子表示，而且与耦合强度参数相关，该参数被建模为假想温度的函数。物理老化效应也被纳入虚拟温度的演变中。通过实验和有限元模拟结果的比较验证了所提出的模型。最后讨论了模型参数的物理意义及其与层合板宏观变形的相关性。