缝合复合材料层间开裂的试验和数值研究

缝合复合材料层合板中贯穿厚度方向的缝线,能有效增强层合板的抗分层能力。本文对一种碳纤/环氧缝合复合材料层板进行了短梁三点弯试验,测得了压头的载荷-位移曲线,并观察了层间裂纹的扩展,证实了缝线对层间裂纹的阻滞作用。建立了三维有限元模型模拟了上述试验,模型中相邻的铺层之间布置了一层初始无厚度的界面单元,界面单元的失效自然模拟层间开裂,而缝线简化为面积等效的梁单元,数值结果与试验观测吻合。

Experimental and numerical study on the delamination fracture of stitched composite laminates

Owing to the existence of through thickness reinforced stitch fiber,the stitched composite laminates possess notably improved delamination resistance.In this study,the three-point bending test was carried out to short beam specimens cut from a carbon fiber/epoxy matrix laminate stitched by Kevlar tows.The load-displacement curves of punch were obtained and the block of stitch tow against delaminating was proven by the observation.A three dimensional FE model was developed to simulate the experiment mentioned above.A layer of interface element was placed between neighbor laminas.The failure of the interface element represents the delamination fracture.The stitch tows in the model were simplified as beam elements.The simulation agrees well with the experimental results.