Thermal shrinkage in polymeric tire cords greatly influences tire dimensions and performance. In order to reduce the undesirable effects of this phenomenon, the Post Cure Inflation (PCI) process is used as a step in tire manufacturing. Finite element analysis of such a complex process requires the consideration of thermal shrinkage, creep, and change in material stiffness for both the cords and the rubber materials. This work focuses on the development of a tire cord material model, which accounts for thermal shrinkage and its related effects. A thermomechanical finite strain rebar element is formulated to enable the representation of the cords within the tire geometry. The proposed cord material distinguishes recoverable from unrecoverable shrinkage to allow a more general description of different types of polymeric cords. A temperature, stress and time dependent thermal shrinkage evolution law is introduced. Moreover, mechanical creep and stiffness variations due to temperature change and shrinkage are considered. The developed formulation is validated against several experimental data obtained for tire cords. Curing and PCI process of a tire segment are also simulated to investigate the effect of thermal shrinkage on the resulting tire dimensions.

聚合物轮胎帘线的热收缩极大地影响轮胎尺寸和性能。为了减少这种现象的不良影响，后硫化充气 (PCI) 工艺被用作轮胎制造中的一个步骤。这种复杂过程的有限元分析需要考虑帘线和橡胶材料的热收缩、蠕变和材料刚度的变化。这项工作的重点是开发轮胎帘线材料模型，该模型解释了热收缩及其相关影响。制定了热机械有限应变钢筋元素，以实现轮胎几何形状内的帘线的表示。所提出的帘线材料将可恢复的收缩与不可恢复的收缩区分开来，以便更一般地描述不同类型的聚合物帘线。一个温度计，介绍了应力和时间相关的热收缩演化规律。此外，还考虑了由于温度变化和收缩引起的机械蠕变和刚度变化。针对轮胎帘子线获得的几个实验数据验证了开发的配方。还模拟了轮胎段的固化和 PCI 过程，以研究热收缩对最终轮胎尺寸的影响。