基于非正交本构模型的热塑性机织物预浸料宽温域赋形褶皱缺陷仿真方法

A simulation method of forming wrinkle defects in thermoplastic woven fabric prepregs in a wide temperature range based on non-orthogonal constitutive model

热塑性复合材料预制体的赋形质量直接影响结构件的制造质量。由于热塑性基体具有较高的熔融温度和黏度,赋形工艺温度设计不合理会导致褶皱等赋形缺陷,给热塑性复合材料结构高质量成型带来了挑战。现有的热塑性预浸料热成型研究主要基于连续介质力学、离散元、半离散元法,通过建立多机制耦合的本构模型分析热塑性预浸料的各向异性大变形行为,未充分考虑工艺调控对赋形宏观变形过程中褶皱缺陷的影响。发展了一种热塑性预浸料宽温域赋形褶皱缺陷仿真方法。通过表征热塑性机织物预浸料在不同温度、载荷下的力学性能,获取宽温域热塑性预浸料本构参数,基于非正交本构模型,提出了温度对热塑性预浸料赋形褶皱缺陷的作用规律,揭示了赋形过程中宽温域褶皱缺陷的变形机制,获得了赋形温度优化调控方案。研究结果表明:褶皱缺陷的萌生和演化过程由不同温度下的面内剪切和压缩变形行为共同影响,预浸料的褶皱缺陷变形程度随温度的增加而减弱,非正交本构模型的模拟结果与实验结果基本一致。

The forming quality of thermoplastic composite preforms directly affects the manufacturing quality of structure.Due to the high melting temperature and viscosity of thermoplastic matrix,unreasonable design of forming process temperature will lead to forming defects such as wrinkles,which brings challenges to high-quality forming of thermoplastic composite structures.Currently,the existing researches on thermoforming of thermoplastic prepregs are mainly based on the continuous,the discrete and the semi-discrete approaches,the anisotropic large deformation behavior of thermoplastic prepreg is analyzed by establishing a multi-mechanism coupled constitutive model,which is not fully considered the influence of process control on wrinkle defects during forming macroscopic deformation.In this paper,a simulation method of forming wrinkle defects in thermoplastic prepregs in a wide temperature range was developed.By characterizing the mechanical properties of thermoplastic woven fabric prepregs at different temperatures and loads,the non-orthogonal constitutive model parameters of thermo-plastic prepregs in a wide temperature range were obtained.The effect of temperature on forming wrinkle defects in thermoplastic prepregs was proposed,and the deformation mechanism of wrinkle defects in a wide temperature range in the forming process was revealed,and the optimal control scheme of forming temperature was obtained.The research results show that the initiation and evolution of wrinkle defects has been affected by the in-plane shear and compressive deformation behaviors at different temperatures,the deformation degree of wrinkle defects of prepreg has been decreased with the increase of temperature.The simulation results of the non-orthogonal constitutive model are basically closer to the experimental results.