Compaction deformations in a thermoplastic composite system molded from chopped prepreg platelets were analyzed to obtain statistical distributions of local distortions that define the final consolidated meso-structure. This study provides an insight into and allows quantification of the intrinsic geometric variability of the composite meso-structure that controls the variability of the effective composite mechanical properties. A two-phase viscoelastic finite element model was utilized to treat the behavior of molten prepreg platelets, which were assumed to be incompressible and inextensible in the fiber direction during processing. A two-step simulation procedure with discretely modeled platelets and platelet-to-platelet contacts is proposed. The analysis begins with a drop simulation of the uncontrolled material deposition followed by a 3D finite element analysis of the preform compaction and bulk material flow. The proposed model provides a method for generating a composite meso-structure ab initio starting from a statistical sampling of the initial conditions for platelet deposition. The predicted platelet thickness distribution, intra-platelet fiber waviness and out-of-plane platelet undulations were found to be in good agreement with experimental measurements. An estimate of the volume of resin pockets was inferred from the compaction simulation.

分析了由切碎的预浸料片制成的热塑性复合材料系统中的压实变形，以获得确定最终固结细观结构的局部变形的统计分布。这项研究提供了洞见，并允许量化复合介观结构的内在几何变异性，从而控制有效复合材料力学性能的变异性。利用两阶段粘弹性有限元模型来处理熔融的预浸料薄片的行为，假定该薄片在加工过程中在纤维方向上不可压缩且不可扩展。提出了具有离散建模血小板和血小板与血小板接触的两步仿真程序。该分析开始于不受控制的材料沉积的液滴模拟，然后是预成型坯的压实和散装物料流的3D有限元分析。提出的模型提供了一种生成复合细观结构的方法从头开始，从对血小板沉积的初始条件的统计采样开始。发现预测的血小板厚度分布，血小板内纤维波纹度和平面外血小板波动与实验测量值非常吻合。从压实模拟可以推断出树脂袋的体积。