缝合密度对缝合/VARI成型复合材料力学性能的影响

Effect of stitch density on mechanical properties of stitched composites manufactured by VARI process

采用改进锁式缝合和真空辅助树脂注射(VARI)成型工艺制备不同缝合密度的碳纤维/环氧树脂复合材料,研究缝合行距和缝合针距对复合材料力学性能的影响,得出最佳缝合密度。结果表明:随着缝合行距的增大,拉伸性能和弯曲性能均有所提升,层间剪切强度先增大后减小;随着缝合针距的增大,拉伸性能和弯曲性能均有提高的趋势;当缝合密度为5 mm×8 mm时,缝合复合材料具有最佳的综合力学性能,与未缝合复合材料相比,拉伸强度和模量分别下降了13.3%和12.7%,弯曲强度和模量分别下降了23.0%和25.2%,层间剪切强度提高了11.3%。

The carbon fiber/epoxy resin composites with different stitch density were manufactured using modified lock stitching and vacuum assisted resin infusion(VARI)molding process.The influence of stitch space and stitch pitch on mechanical properties of the composites was investigated.The optimum stitch density was obtained.The results show that with increasing stitch space,both tensile and flexural properties enhance and interlaminar shear strength increases first and then decreases.With the increase of stitch pitch,both tensile and flexural properties exhibit an increasing trend.The stitched composites have the optimum integrated mechanical properties when the stitch density is 5 mm×8 mm.Their tensile strength,tensile modulus,flexural strength and flexural modulus reduce by 13.3%,12.7%,23.0%and 25.2%,respectively,whereas the interlaminar shear strength increases by 11.3%compared to the unstitched composites.