Stamp forming with thermoplastic composites provides high-rate production of structural components. A series of physical phenomena develops concurrently as a blank of fiber reinforced thermoplastic is consolidated, reheated, stamp formed, and cooled within the tool, and released from the tool in the stamp forming process. Transient phenomena contributing to the residual deformation of continuous fiber-reinforced thermoplastics processed by stamp forming were described and characterized in this work. The transient phenomena considered included anisotropic heat transfer, anisotropic shrinkage, thermoviscoelastic behavior, and semi-crystalline polymer melting and crystallization kinetics. A comprehensive experimental characterization of the material properties required to model the phenomena involved in shape change is summarized in this work. The digital twin of this process, termed FORM3D and based on the finite element solvers ABAQUS and ANIFORM, has been constructed with the goal of describing the important phenomena in thermoplastic stamp forming, particularly to predict shape change. Shape change predictions made with FORM3D were validated against experimental measurements for a double curvature geometry made with a quasi-isotropic stacking sequence. The double curvature geometry developed both spring-in and spring-out deformations in the minor and major radii of curvature, respectively. FORM3D predictions were in excellent agreement with the experiments in both magnitude and distribution of the deformation. The same correlation was observed for three repetitions of the stamp formed experiment carried out in this work.

中文翻译：

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碳纤维热塑性复合材料层压板冲压成型形状变化预测的验证

使用热塑性复合材料冲压成型可实现结构部件的高生产率生产。当纤维增强热塑性塑料坯料在工具内固结、重新加热、冲压成形和冷却，并在冲压成形过程中从工具中释放时，会同时发生一系列物理现象。这项工作描述并表征了通过冲压成型加工的连续纤维增强热塑性塑料产生残余变形的瞬态现象。考虑的瞬态现象包括各向异性传热、各向异性收缩、热粘弹性行为以及半结晶聚合物熔融和结晶动力学。这项工作总结了模拟形状变化所涉及的现象所需的材料特性的全面实验表征。该过程的数字孪生称为 FORM3D，基于有限元求解器 ABAQUS 和 ANIFORM，其构建目的是描述热塑性冲压成形中的重要现象，特别是预测形状变化。使用 FORM3D 进行的形状变化预测通过准各向同性堆叠序列制成的双曲率几何体的实验测量进行了验证。双曲率几何形状分别在小曲率半径和主曲率半径上产生弹入和弹出变形。FORM3D 预测在变形的大小和分布方面与实验非常一致。在这项工作中进行的冲压成形实验的三次重复中观察到相同的相关性。