开孔三维机织复合材料的拉伸性能

Tensile properties of 3-D woven composites with holes

为研究开孔尺寸对三维机织复合材料拉伸力学行为、破坏模式以及失效机制的影响规律,设计了3种不同孔径的三维机织复合材料试样,利用非接触全场应变测试系统和显微图像技术进行表征。结果表明:6、10、14 mm的孔径对三维机织复合材料的拉伸模量几乎没有影响,开孔后全截面拉伸强度分别下降35.6%、44.5%和51.8%,但开孔后的净截面拉伸强度基本相同,与未开孔试样相比,平均拉伸强度下降约22.4%;未开孔试样的全场应变呈现均匀分布,而开孔试样在孔左右两侧呈现出应变集中;开孔试样的断口形貌相似,主要表现为经纱的断裂,并伴随有部分纱线的抽拔以及层间开裂。

In order to investigate the effect of aperture on the tensile mechanical behavior,damage mode and failure mechanism of three-dimensional(3-D)woven composites with holes,three types of 3-D woven composite samples with different hole apertures were designed and digital image correlation system and micro-image technique were used for characterization.The results showed that the dimension of holes had little effect on the tensile modulus of 3-D woven composites,but the tensile strengths of the cross section of notched specimens with 6 mm,10 mm and 14 mm holes decreased by 35.6%,44.5%and 51.8%respectively.Their tensile strengths of the net section however were almost the same,and the average tensile strength decreased by approximately 22.4%compared with the unnotched samples.The strain distributions of the unnotched specimen were uniform,while the strains of the notched specimens were mainly located at the left and right sides of the open holes.The fracture morphologies of the three notched samples were similar,and the main damage modes were the warp fracture along with fiber pull-out and interlaminar cracking.