In the field of material modeling, thermoplastic polymers are often studied because of their complex material behavior and their prevalence in industry applications due to their low cost and wide range of applications. Nowadays, where reusability becomes more and more important, materials which can undergo reversible thermomechanical deformations are appealing for, e.g., the construction of car body components. To predict such complex forming processes with multiple influencing factors, such as temperature, strain rate or underlying material morphology, model formulations are needed that account for these influences simultaneously and are validated against experimental data. Unfortunately, up to now only a few contributions are available which consider all these phenomena. In addition, the range of process parameters considered is often narrow due to the experimental effort required for testing. This usually results in limited predictive capabilities of the model. To overcome these limitations, in this work, a thermo-mechanically coupled material model is developed that accounts for the underlying morphology in terms of the degree of crystallinity (DOC). The model formulation is derived in a thermodynamically consistent manner, incorporating coupled nonlinear visco-elastic and elasto-plastic material behavior at finite strains. To characterize and further validate the model, mechanical as well as thermal experiments are conducted for polyamide 6 (PA6). Here, a blending strategy of PA6 together with an amorphous co-polymer is introduced during specimen production to achieve a wider range of stable DOCs(approximately 15%). The model formulation is successfully applied to experimental results and its predictions are in good agreement with experimental observations.

在材料建模领域，热塑性聚合物因其复杂的材料行为而经常被研究，并且由于其低成本和广泛的应用而在工业应用中普遍存在。如今，可重复使用性变得越来越重要，能够经历可逆热机械变形的材料对于例如车身部件的构造很有吸引力。为了预测具有多种影响因素（例如温度、应变率或基础材料形态）的复杂成形过程，需要同时考虑这些影响并根据实验数据进行验证的模型公式。不幸的是，到目前为止，只有少数贡献考虑了所有这些现象。此外，由于测试所需的实验工作量，所考虑的工艺参数范围通常很窄。这通常会导致模型的预测能力有限。为了克服这些限制，在这项工作中，开发了一种热机耦合材料模型，该模型根据结晶度 (DOC) 来解释潜在的形态。该模型公式以热力学一致的方式导出，结合了有限应变下耦合的非线性粘弹和弹塑性材料行为。为了表征并进一步验证模型，对聚酰胺 6 (PA6) 进行了机械和热实验。在此，在样品生产过程中引入了 PA6 与无定形共聚物的共混策略，以获得更广泛的稳定 DOC（约 15%）。该模型公式成功应用于实验结果，其预测与实验观察结果吻合良好。