L形层板真空袋成型缺陷的实验研究

采用真空袋阳模成型法在不同条件下制备了90°的L形玻纤单向布/环氧树脂层板, 对层板不同位置处纤维密实和缺陷状况进行了研究, 考察了成型过程主要工艺条件对缺陷的影响规律。结果表明, 富树脂、 孔隙、 厚度分布不均和纤维屈曲变形是L形层板中主要的缺陷类型, 加压时机、 层板尺寸、 铺层方式以及边界条件对纤维密实和缺陷的形成都有重要的影响。对以上各种缺陷的产生机制进行了初步分析: 剪切流动的存在导致层板厚度分布不均匀而且出现富树脂区; 纤维的屈曲变形是由于轴向受压缩力; 本文实验条件下孔隙的主要来源是夹杂空气。研究结果对热压工艺中缺陷的预测与控制以及工艺参数的优化具有重要的指导意义。 

Experimental research on defects of L-shape laminates in vacuum-bag process

The 90° L-shape laminates under different conditions were prepared in the vacuum-bag process with the convex tool for unidirectional glass fabric/epoxy resin, and the state of the fiber compaction and defects at different positions were investigated. The experiments were designed to study the effects of the processing conditions on the defects. The results indicate that the redundant resin, void, thickness variation and fiber buckling are the main defect types in the L-shape laminates. In addition, the time of applying pressure, laminate dimension, type of lay-up and edge conditions have significant effects on the fiber compaction and the forming of defects. The mechanisms of the defects forming were analyzed. The thickness variation and the redundant resin are caused by shear flow, the fiber buckling results from axial compression, and entrapped air is the main source of void under the experiment conditions. The results provide important guidances for defects control and processing parameters optimizing in the hot press process.