热塑性预浸料赋形褶皱缺陷的全局灵敏度分析

Global sensitivity analysis of forming wrinkle defects in thermoplastic prepregs

复合材料复杂构件成型过程中极易产生褶皱,影响构件成型质量和承载性能,因而迫切需要建立成型工艺参数对预浸料褶皱的定量映射关系,支撑构件的低缺陷成型制造。本文发展了一种多工艺参数耦合的热塑性预浸料褶皱缺陷全局灵敏度分析方法。基于非正交本构模型发展了热塑性预浸料宽温域赋形变形有限元仿真方法,将预浸料与模具的距离和预浸料面外弯曲的曲率相结合,提高了褶皱缺陷定量表征的可靠性,最终采用基于方差的Sobol全局灵敏度指标,建立了一套能够定量计算赋形工艺参数对褶皱缺陷影响程度的全局灵敏度分析方法。通过典型平纹碳纤维/聚碳酸酯(CF/PC)材料单穹顶成型过程验证,结果表明:在200~250℃温度范围和0.2~2.0 kPa压强范围内,赋形温度对CF/PC预浸料褶皱缺陷的影响大于赋形压强,而且赋形过程中存在温度和压强的双参数耦合作用。

Wrinkles are easily produced during the forming process of complex composite structures,which affect the forming quality and load-bearing performance of the components.It is urgent to establish the quantitative mapping relationship between forming process parameters and prepreg wrinkles to support the low-defect forming manufacturing of components.In this paper,a global sensitivity analysis method for wrinkled defects in thermoplastic prepregs coupled with multiple process parameters is proposed.A finite element simulation method based on a non-orthogonal constitutive model is developed for the wide temperature domain deformation of thermoplastic prepreg.Combining the distance between the prepreg and the mold and the curvature of the out of plane bending of the prepreg improves the reliability of quantitative characterization of crease defects.Finally,a global sensitivity analysis method was established using the Sobol global sensitivity index based on variance,which can quantitatively calculate the impact of forming process parameters on wrinkle defects.It is verified through the typical carbon fiber/polycarbonate(CF/PC)material single dome forming process.The results show that in the temperature range of 200-250℃and the pressure range of 0.2-2.0 kPa,the influence of temperature on the wrinkling forming wrinkle defects in thermoplastic defects of CF/PC prepreg is greater than that of pressure,and there is a dual parameter coupling effect of temperature and pressure during the forming process.