VIMP中结构拐角对纤维预成型体渗透特性的影响

采用真空导入模塑工艺(VIMP)制备纤维增强聚合物基复合材料多墙结构件时,多墙体拐角处的纤维弯曲变形可能导致多墙体局部渗透特性发生变化。通过可视化流动实验考察了拐角对多墙体渗透特性和树脂流动行为的影响。结果表明:无论是否使用导流介质,多墙体中的拐角对树脂流体在VIMP灌注过程中都具有局部阻力作用,降低了树脂充模流动速度和多墙体整体表观渗透率,即存在拐角效应;拐角处铺放导流介质能有效降低拐角效应;随着拐角到注胶口的距离增大,整体表观渗透率表现为先下降后上升。

Effects of structural corner on permeability of fiber preform in VIMP

In the manufacture of multi-walled composite structures with fiber reinforced polymer composites by the vacuum infusion molding process (VIMP), the local multi-walled permeability is changed at the corners of multi-walled structure due to the fiber bending deformation. The effects of corner on multi-walled permeability and resin flow behavior were investigated by the visual flow experiments. The results show that, regardless of the application of distribution medium, the resin molding flow rate and overall multi-walled apparent permeability would be decreased due to the corner effect. This behavior is ascribed to the local resistance effect of the corners applied to the resin in filling process of VIMP. The corner effect can be weakened through applying distribution medium to the corners. When the distance between the corner location and the injection gate becomes larger, the overall apparent permeability will decrease first, and then increase.