Thermoforming of continuous fiber-reinforced plastics made of semi-crystalline thermoplastics has gained significant interest due to its potential for producing lightweight and high-strength components for various applications. Before thermoforming, a laminate is heated to a temperature beyond the melting point of the thermoplastic. During the subsequent forming process, the laminate is continuously cooled, which triggers non-isothermal crystallization in the semi-crystalline matrix material. In this context, the study of crystallization kinetics is crucial in identifying phase transition, analyzing exothermic latent heat during crystallization and determining inhomogeneous crystallinity distribution caused by uneven cooling in the laminate’s thickness direction. This contribution primarily deals with experimental investigations, modeling and finite element simulations for characterizing the crystallization kinetics in the matrix material, Polyamide 6 and investigating the aforementioned factors. To model the crystallization kinetics, an extended form of the Avrami model, known as the modified Nakamura–Ziabicki model, is adopted. The parameters for the modified Nakamura–Ziabicki model, which depend on the local cooling rates, are identified based on fitting the model to flash DSC (differential scanning calorimetry with high cooling rates) and standard DSC non-isothermal cooling experiments. Finally, the model is implemented into the commercial FE software COMSOL Multiphysics^® and the crystallinity evolution in the laminate is simulated for the process-relevant die and laminate temperatures and laminate thicknesses.

由半结晶热塑性塑料制成的连续纤维增强塑料的热成型因其在生产各种应用的轻质和高强度部件方面的潜力而引起了人们的极大兴趣。在热成型之前，层压板被加热到超过热塑性塑料熔点的温度。在随后的成型过程中，层压板不断冷却，从而引发半结晶基体材料的非等温结晶。在这种情况下，结晶动力学的研究对于识别相变、分析结晶过程中的放热潜热以及确定由层压板厚度方向不均匀冷却引起的不均匀结晶度分布至关重要。该贡献主要涉及实验研究、建模和有限元模拟，以表征基体材料聚酰胺 6 的结晶动力学并研究上述因素。为了模拟结晶动力学，采用了 Avrami 模型的扩展形式，称为改进的 Nakamura-Ziabicki 模型。修改后的 Nakamura-Ziabicki 模型的参数取决于局部冷却速率，通过将模型拟合到快速 DSC（高冷却速率的差示扫描量热法）和标准 DSC 非等温冷却实验来确定。最后，该模型被应用到商业有限元软件 COMSOL Multiphysics ^®中，并针对与工艺相关的模具和层压板温度以及层压板厚度模拟层压板中的结晶度演变。