炭/环氧复合材料拉伸损伤声发射特性及细观力学分析

Acoustic Emission Characters of Carbon/Epoxy Composite Subjected to Tensile Damage and Its Micromechanics Analysis

对单向碳/环氧复合材料拉伸断裂过程进行了声发射监测,结合拉伸过程的细观力学分析,探讨了复合材料拉伸断裂的机理。结果表明,碳/环氧复合材料拉伸损伤过程可以分为三个阶段:弹性变形阶段、损伤发展与累积阶段和临近断裂阶段。弹性变形阶段基本无明显损伤发生;损伤发展与累积阶段主要是基体及界面损伤,该损伤先随载荷快速增大,到达峰值后又迅即减小;临近断裂阶段时声发射信号相对平静,但炭纤维开始发生集群损伤,这预示了灾难性断裂的到来。应用三维单胞模型,分析了引起各阶段损伤的原因。

Acoustic emission technology（AE） was applied to monitor the damage of the carbon/epoxy composite during its tensile experiment.The results show that the whole damage of carbon/epoxy composite can be divided into three stages along loading history： the stage of elastic deformation,the stage of damage developing and accumulating,the stage of critical fracture nearing.There is very little damage accuring in the first stage.During the second stage,the damage mainly comes form the fracture of epoxy and interface,with the tendency that the damage increases at first,then decreases quickly after it reaches its peak value.In the last stage,the carbon fibers begin to damage and fracture.This damage predicts that the critical fracture is coming,becuse final fracture will occur short time after that damage.The three dimension unit cell finite element model was applied to analyze the cause which arouses the damage and explain AE characters of the material.