摘要
由于碳纤维和Kevlar纤维力学性能相差迥异,在C-K纤维混杂增强复合材料(Carbon-Kevlar fiber hybrid composite,CKFH)加工中易产生加工缺陷,比单种纤维复合材料的加工缺陷更难控制。由此,从微观和宏观角度,构建CKFH三维有限元切削模型,分析CKFH的切削去除机理及平纹编织结构对切削过程的影响机制。结果表明,在不同纤维取向下,Kevlar纤维均易产生抽丝拉毛现象,尤其当纤维取向θ=0°/180°时最为明显;纤维取向θ=0°/180°时,切屑多为卷曲片状切屑,纤维取向θ=45°、90°、135°时,两种纤维的断裂相互影响,切削表面、切屑形态均与切削方向存在密切关系,当纤维取向θ=45°时,多为细小片状切屑,纤维取向θ=90°时,切屑多为絮状块状切屑,纤维取向θ=135°时,切屑多为成块状切屑;从碳纤维切向Kevlar纤维时,Kevlar纤维出现松散、抽丝拉毛现象明显,从Kevlar纤维切向碳纤维时,在Kevlar纤维的韧性弯曲区碳纤维发生弯曲脆断、碎裂,易出现凹坑;平纹编织结构对切削应力的传递具有明显的阻断作用,有限元仿真结果与试验观测结果基本吻合。
Due to the different mechanical properties of carbon fiber and Kevlar fiber,the processing defects are easy to be induced during the machining of Carbon-Kevlar fiber hybrid composites(CKFH).These defects are more difficult to control than the processing defects of the single fiber reinforced plastics.Then,from the micro and macro perspectives,the three-dimensional finite element cutting models of CKFH are established.The cutting removal mechanisms of CKFH and the influence mechanisms of plain woven structure on the cutting process are analyzed.The results show that the Kevlar fibers are easy to be drawn into some filamentous,especially when the fiber orientationθ=0°/180°.When the fiber orientationθ=0°/180°,the form of chips is mostly curly sheet shape.When the fiber orientationsθ=45°,90°,135°,the two kinds of fiber fracture affect each other,and the cutting surface and chip morphology are closely related to the cutting direction.When the fiber orientationθ=45°,most of the chips are fine flake chips,when the fiber orientationθ=90°,most of the chips are floccule chips,when the fiber orientationθ=135°,most of the chips are lumpy chips.When the cutter cuts the carbon fibers to the Kevlar fibers,the Kevlar fibers appear visibly loose and are drawn into some filamentous.Conversely,when the cutter cuts the Kevlar fibers to the carbon fibers,the carbon fibers in the Kevlar fibers ductile bending zone are brittle and broken by bending.Then,the pit phenomenon is prone to appear.The plain woven structure has an obvious blocking effect on the transfer of cutting stress.The finite element simulation results are basically consistent with the experimental observation results.
作者
苏飞
欧阳晨恺
李纯杰
郑雷
蔡志华
SU Fei;OUYANG Chenkai;LI Chunjie;ZHENG Lei;CAI Zhihua(Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material,Hunan University of Science and Technology,Xiangtan 411201;School of Mechanical Engineering,Yancheng Institute of Technology,Yancheng 224051)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第21期331-348,共18页
Journal of Mechanical Engineering
基金
国家自然科学基金(52175400、51805164)
湖南省自然科学基金(2021JJ30263)
江苏省自然科学基金面上(BK20201474)
湖南省教育厅科研(18A182)资助项目。
