三维编织复合材料压缩力学性能的实验研究

通过宏观压缩实验,研究了三维四向编织复合材料的抗压力学性能;同时,为了认识其压缩失效机理,对压缩试件的破坏断口进行了扫描电镜分析。实验结果表明:纵向压缩模量比横向压缩模量大得多;影响纵向压缩力学性能的主要参数是材料的编织角,随编织角的变化,复合材料的纵向压缩破坏机理发生了变化,编织角较小时,材料表现为脆性特征;当编织角大于某个角度,材料的应力-应变曲线趋于非线性,延性增加,更多地表现为塑性破坏特征。此外,横向压缩的破坏机理与纵向压缩明显不同。

EXPERIMENTAL INVESTIGATION INTO THE COMPRESSIVE MECHANICAL PROPERTIES OF THREE DIMENSIONAL BRAIDED COMPOSITES

The mechanical properties of three dimensional and four-direction braided composites were investigated by the macroscopic compressive experiments, and the SEM analysis was performed for the fracture surface of specimens to understand the compressive failure mechanism of this kind of composite. The experimental results show that the longitudinal modulus is much larger than the transverse one, and the most important parameter to affect the longitudinal compressive properties of the composites is the braided angle. The mechanism of longitudinal compressive failure of the composites changes with the increase of the braided angles. When the braided angle is smaller, the material behaves as the brittle characteristics. But if the braided angle is larger than a certain critical one, the stress-strain curves of the materials approach nonlinear ones and the ductility of the composites increases, behaving mostly as the characteristics of plastic failure. In addition, the mechanism of transverse compressive failure of the composites is significantly different from the one of longitudinal compression.