孔口缝合补强对层间应力影响的数值模拟

FINITE ELEMENT ANALYSIS OF INTERLAMINAR STRESSES OF COMPOSITE LAMINATES STITCHED AROUND A CIRCULAR HOLE

使用空间杆单元模拟缝合线,对含孔复合材料层合板开口缝合补强结构进行有限元模拟计算。研究含孔复合材料层合板在轴向拉伸载荷作用下,圆孔附近各个铺层交界面处层间正应力和剪应力的分布情况,将缝合后的层间应力值与缝合前的相关数值进行比较,并研究不同缝合参数(针距、行距、边距、单缝合和双缝合)对孔边层间应力的影响。结果表明,缝合补强后孔边的层间应力明显减小。孔边附近层间应力的分布与相邻铺层的铺层角有很大关系,不同铺层之间的层间应力有显著差别。不同铺层之间的层间应力沿孔边区域存在应力转换点(即层间应力由正值变为负值)。

The stitching yarns are described by the space bar element, and a finite element modeling techniques are evaluated for the interlaminar stresses analysis of the composite laminates stitched around a circular hole. The interlaminar normal stress and the interlaminar shear stress are computed around the hole which subjected to in-plane tension. The interlaminar stresses of stitched-composites laminate are compared with those of unstitched-composites laminate. The effects of stitching parameters such as stitching needle span, row spacing, edge distance, single stitching or double stitching are discussed on the interlaminar stresses. The results show that the stitched-composites laminate have much lower interlaminar stresses than unstitched-composites laminate. The distribution of the interlaminar stresses around the hole is related with layers. The interlaminar stresses around the hole of different layers are likely to including breaking point.