孔隙对碳纤维/环氧树脂复合材料剪切性能和破坏模式的影响  

Effects of voids on shear properties and failure mode of carbon fiber/epoxy resin composites

作　　者：史俊伟 杨柳 王文贵 荀国立 信泽坤 SHI Junwei;YANG Liu;WANG Wengui;XUN Guoli;XIN Zekun(Laboratory of Composite Nondestructive Testing and Evaluation Technology,AVIC Manufacturing Technology Institute,Beijing 101300,China)

机构地区：[1]中国航空制造技术研究院复合材料检测与评估技术室,北京101300

出　　处：《复合材料学报》2024年第9期5039-5052,共14页Acta Materiae Compositae Sinica

摘　　要：孔隙对碳纤维/环氧树脂复合材料剪切性能的影响十分显著。本文采用吸湿饱和和固化压力阶梯下降的方法在复合材料层压板中模拟制备出不同含量的孔隙缺陷,通过短梁剪切强度测试试验,建立不同孔隙率对短梁剪切强度的影响曲线,结合金相观察和超声成像分析了不同孔隙率下损伤分布与破坏模式。研究结果表明:当孔隙率小于1.0%时,短梁剪切强度保留率约为88.4%~90.8%;当孔隙率增加至1.0%~1.5%时,短梁剪切强度保留率约为74.9%~80.6%;当孔隙率增加至1.5%~2.0%时,短梁剪切强度保留率约为66.3%~71.9%;当孔隙率增加至2.0%~3.0%时,短梁剪切强度急剧下降,短梁剪切强度保留率降至50%以下。短梁剪切破坏模式对孔隙缺陷十分敏感,层剪破坏主要发生在孔隙及其周边应力集中的区域,孔隙对裂纹的萌生和扩展具有明显的促进作用。Voids have significant influence on the shear properties of carbon fiber/epoxy resin composites.In this paper,carbon fiber/epoxy resin composite laminates with varies porosity were produced by hygroscopic saturation and stepping down the autoclave pressures.Short beam shear(SBS)tests were performed to establish the influence curve of different porosity on SBS strength.The evolution of shear damage induced by voids and the degradation mechanism of SBS strength were both studied by ultrasonic imaging and metallographic observation.The result shows that when the porosity is less than 1.0%,the SBS strength retention rate is about 88.4%-90.8%;When the porosity increases to 1.0%-1.5%,the SBS strength retention rate is about 74.9%-80.6%;When the porosity increases to 1.5%-2.0%,the SBS strength retention rate is about 66.3%-71.9%;When the porosity increases to 2.0%-3.0%,the SBS strength decreases sharply,and the SBS strength retention rate drops below 50%.The SBS shear failure mode is very sensitive to voids.Shear failure mainly occurs close to void and the surrounding stress concentration.The higher the porosity,the more obvious the promotion effect of voids on crack initiation and propagation,yielding the higher crack density,the earlier crack occurrence time,and the faster propagation speed.

关 键 词：复合材料 孔隙率 破坏模式 短梁剪切强度 裂纹萌生 

分 类 号：TB332[一般工业技术—材料科学与工程]