三维多向编织复合材料压缩性能的试验研究

Experimental investigation on longitudinal compression properties of 3D multidirectional braided composite

采用短标距薄板试件法对三维五向和六向编织复合材料试件进行了压缩试验。该方法可以避免试件产生整体屈曲和端部纤维束开裂破坏,适用于三维编织复合材料的压缩试验。同时,在试验的基础上,分析了该类材料的纵向压缩刚度、压缩强度和泊松比随编织工艺参数的变化规律以及材料的失效形式。三维五向和六向编织复合材料在破坏前基本保持线弹性,纵向压缩破坏具有脆性特征。编织角的增大导致了材料纵向压缩性能下降。减小四向编织纱线的细度,有利于提高材料的纵向压缩性能。此外,三维六向编织复合材料的纵向压缩性能低于三维五向编织复合材料。

Compression tests for the 3D 5-directional and the 3D 6-directional braided composites were conducted by using shot-gauge plate sample method. The method can avoid buckling of sample and cracking of end fiber bundle, which is suitable for compression tests of 3 D multidirectional braided composites. On the basis of tests, the change law of longitudinal compression stiffness, compression strength, Poisson＇s ratio with braiding process parameters and failure mode of composite were analyzed. The 3D 5-directional and the 3D 6-directional braided composites keep linear elastic; longitudinal compression failure is of brittleness. The increase of braiding angle makes longitudinal compression properties decrease; the decrease of fineness of 4-directional braided yarns tends to improve the longitudinal compression properties of materials. Moreover,the longitudinal compression properties of 3D 6-directional braided composites are lower than that of 3D 5-directional braided composites.