Abstract During the service of shape memory polymer (SMP), the thermal-mechanical cycle is a necessary process. Meanwhile, the influence of the viscoelastic properties of SMP, such as rate-dependent behaviors, can not be ignored during the application. Consequently, a constitutive model based on the multiplicative decomposition of the deformation gradient is proposed in this work, which can clearly describe the viscoelastic behavior and capture the thermal-mechanical cycle process of SMP. By introducing the “phase transition” concept, SMP is assumed as a composite composed of glassy phase and rubbery phase, and the volume fractions of each phase vary with temperature. Furthermore, according to the different mechanical behaviors of the glassy phase and rubbery phase, two different constitutive structures that can describe the strain sensitivity of SMP are developed to represent the mechanical response. The developed model was verified by simulating a series of experiments, including strain sensitivity tests and thermal-mechanical cycle experiments.

中文翻译：

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基于变形梯度乘法分解的形状记忆聚合物热力学行为预测

摘要 在形状记忆聚合物（SMP）服役过程中，热-机械循环是一个必要的过程。同时，SMP 的粘弹性特性的影响，如速率依赖行为，在应用过程中也不容忽视。因此，本文提出了一种基于变形梯度乘法分解的本构模型，该模型可以清楚地描述粘弹性行为并捕获 SMP 的热机械循环过程。通过引入“相变”概念，SMP被假设为由玻璃相和橡胶相组成的复合材料，每相的体积分数随温度变化。此外，根据玻璃相和橡胶相的不同力学行为，开发了两种可以描述 SMP 应变敏感性的不同本构结构来表示机械响应。通过模拟一系列实验，包括应变敏感性测试和热机械循环实验，对开发的模型进行了验证。