损伤形式对三维编织复合材料拉压性能的影响

通过对损伤前后三维编织复合材料试件进行纵向拉伸和压缩实验, 分析了材料的拉、压刚度和强度的变化规律和失效形式。主要讨论了4 种损伤加工方案, 包括沿宽度方向单边切割、沿宽度方向双边切割、沿厚度方向单边切割及沿宽度和厚度方向同时切割。实验结果表明, 宽度方向损伤对拉伸强度、模量和压缩强度影响不大, 压缩模量下降了20 %左右; 厚度方向损伤对纵向拉伸、压缩强度和模量影响较大。编织角20°时, 拉伸、压缩应力-应变曲线接近于线性, 试件的失效方式趋向于脆性破坏; 编织角35°时, 压缩应力-应变曲线表现出一定的非线性。 

Influence of damage style on tensile and compressive propertiesof three-dimensional braided composites

The longitudinal tensile and compression test s were conducted on the pre-damaged three-dimensionalbraided composites. The varying rules of tensile and compressive properties and the failure mechanism of the materials were investigated. Four kinds of damage processes were discussed , single-edge cut on the width , single-edgecut on the thickness , double-edge cut on the width and edge cut on the thickness and width. Experimental resultsreveal that the cut edge on the width of specimen barely affects the longitudinal properties , except that the compressive modulus deduces by 20 %; while cut on the thickness makes a relatively great deduction on the properties.When the surface angle is 20°, stress-strain curves of tension and compression tend to linearity , and the failuremechanism has brittle f racture characteristics ; when the surface angle is 35°, the stress-strain curves of compressionexpress non-linearity to some extent .