未固化预浸料在热模压预成型过程中的黏弹性行为研究

Investigation of the viscoelastic behavior in the hot press-forming process of uncured prepreg laminates

在热模压预成型过程中,压力对最终产品的性能和质量有重要影响。本文研究了未固化预浸料层合板在不同铺层方向、压缩距离、压缩速度及厚度下的压缩和松弛行为。结果表明,幂律模型能准确描述热模压过程中预浸料受外力压缩时的应力变化,广义Maxwell模型和考虑应变历史的分数阶黏弹性模型能描述预浸料的应力松弛过程,拟合曲线与实验点吻合良好,R^(2)均大于0.96。相较于广义Maxwell模型,分数阶黏弹性模型所需确定的参数少,物理意义明确,更适合描述预浸料在热模压过程中应力松弛时的黏弹性变形过程。

In the pre-forming process of uncured prepreg laminates with hot press, pressure is an important parameter that affects the performance and quality of the final product. In this study, the compression and relaxation viscoelastic behaviors of uncured prepreg laminates were investigated in different fiber orientation, displacements, velocities, and thicknesses. The results show that the power law model could accurately describe the compression behaviors of prepreg. The generalized Maxwell viscoelastic model and the fractional viscoelastic model could describe the relaxation behaviors of prepreg, respectively. The theoretical fitting curves match very well with experimental data at each condition and the R-squared value is greater than 0.96. Compared with the generalized Maxwell model, the fractional viscoelastic model requires fewer parameters and has more definite physical significance, which is more suitable for describing the viscoelastic deformation behaviors of prepreg in the process of hot press-forming.