CFRP复合材料层间增韧结构优化

Investigation on the Interlaminar Interleaving Structure of CFRP Composites

采用T700/6240碳纤维/环氧树脂预浸料和自制热塑性酚酞基聚醚酮(PEK-C)增韧膜,通过热压成型工艺制备不同层间增韧结构复合材料层合板,对其进行低速冲击、冲击后压缩及三点弯曲实验,并结合扫描电子显微镜(SEM)微观形貌表征及数学优化思想,确定最佳增韧结构。结果表明,在不同位置铺设12层增韧膜的四组试样中,中部增韧效果最佳,其冲击后压缩强度(CAI)比未增韧时提高42.39%。在层合板中部铺设8、16和23层增韧膜的试样,CAI和弯曲强度随增韧膜数量的增加分别呈现递增和递减趋势。通过弯曲试样SEM形貌表征发现,随增韧膜数量的增加,裂纹纵向扩展受到抑制,且由于环氧树脂与PEK-C的相容性较差,出现局部分层损伤。结合总增益和单层增益函数变化趋势,确定最佳增韧结构为层合板中部铺设11或12层增韧膜。

The carbon fiber/epoxy(T700/6240)composites(CFRP)interleaved by polyaryletherketone with Cardo(PEK-C)films were prepared by hot pressing technology.The composites were tested by low speed impact,compressive after impact(CAI)and bending test.Scanning electron microscopy(SEM)was used to characterize the fracture morphology.The optimum interleaving structure was determined by mathematical optimization based on the experimental results.The results show that CFRP laminates interleaved by PEK-C films reveals the highest CAI value,which is 42.39%higher than the no toughening specimen.When the films are interleaved in the middle position of specimens for 8,16 or 23 layers of toughening membrane,the CAI value could increase with PEK-C film increasing and the flexural strength could decrease.The SEM morphology shows that the crack growth along the direction of specimen thickness is inhibited with PEK-C film increasing.In addition,the local delamination is examined,which might be attributed to the poor compatibility of epoxy resin and PEK-C.Based on the total gain and single-layer gain functions,the optimum interleaving structure is 11 or 12 PEK-C films in the middle position of the laminates.