缝合参数对复合材料板面内刚度和强度影响研究

EFFECTS OF STITCHING PARAMETERS ON IN-PLANE STIFFNESS AND STRENGTH OF COMPOSITE LAMINATES

通过数值计算和对37组158个试件的实验测试与分析,研究了四种缝合参数对缝合复合材料板面内刚度和强度的影响。结果表明:1)缝合密度越大,缝合所产生的损伤就越大,对面内刚度的影响也就越大。几种常用缝合密度下的面内刚度差最大为纵向6%,横向11%,剪切9%;2)缝合密度和缝合工艺水平对面内拉伸强度和剪切强度有很大影响,缝合引起的拉伸强度和剪切强度降低分别达14%和17%,而对面内压缩强度的影响很小,最大强度降不到4%。3)当缝线方向与测试方向垂直时,可以得到较高的面内刚度值和较低的面内强度值。反之,当缝线方向与测试方向平行时,可以得到较低的面内刚度值和较高的面内强度值。最大变化幅值分别为21%和18%。

The effects of four kinds of stitch parameters on the in-plane stiffness and strength of stitched composite laminates are investigated by both numerical calculation and experiments of 158 specimens in 37 groups. Results show that, （1） the greater the stitch density is, the greater the damage by stitch and the effect on in-plane stiffness and strength are. The maximum in-plane stiffness differences at several kinds of ordinary stitch density are 6%, 11% and 9% in longitudinal, transversal and shear directions, respectively. （2） The stitch density and perfection have great influences on the in-plane tension and shear strength. The maximum reductions of the in-plane tension and shear strengths resulting from stitching are 14% and 17%, respectively, while less than 4% reduction is gained for compression strength. （3） When the stitching threads go in the direction perpendicular to that of property measurement, higher in-plane stiffness and lower in-plane strength are achieved. Otherwise, when the stitching threads go in the direction parallel to that of property measurement, lower in-plane stiffness and higher in-plane strength result. The maximum differences of the in-plane stiffness and in-plane strength are 21% and 18%, respectively.