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DOI: 基于内埋光纤光栅传感器的复合材料固化过程监测 耿湘宜1, 王静1, 姜明顺1, 隋青美1, 刘刚2, 李盼3, 贾玉玺3, 贾磊*1 (1.

山东大学 控制科学与工程学院, 济南 250061;

2. 北京航空材料研究院 先进复合材料国防科技重点实验室, 北京 100095;

3. 山东大学 材料液固结构演变与加工教育部重点实验室, 济南 250061) 摘要:在对碳纤维增强树脂基复合材料固化变形进行仿真分析的基础上,将自行设计的光纤Bragg光栅(FBG)传感器埋入复合材料中,实时在线监测复合材料固化过程中温度和应变的演变.预浸料铺层方式为[011/9011],分别在层合板的0°和45°方向的典型位置埋入FBG温度和应变传感器,采用热模压方式固化成型复合材料,并对成型后的层合板进行连续两次降温处理,实时记录固化过程中FBG传感器中心波长的变化.结果发现: 在相同温度条件下复合材料在第一次降温的初始阶段的压应变绝对值明显小于在第二次降温的初始阶段的压应变绝对值,表明复合材料在第一次降温过程中仍在进行FBG可检的 后固化 反应.层合板变形的FBG监测数据与有限元模拟结果吻合良好.因此,采用内埋FBG传感器的方法能够实时监测复合材料固化过程,为更全面地分析复合材料固化特性提供了一种可靠有效的方法. 关键词:复合材料;

固化变形;

光纤Bragg光栅;

过程监测;

有限元模拟 中图分类号: TB332 文献标志码:A Monitoring of composite materials curing process based on embedded fiber Bragg grating sensors GENG Xiangyi1, WANG Jing1, JIANG Mingshun1, SUI Qingmei1, LIU Gang2, LI Pan3, JIA Yuxi3, JIA Lei*1 (1. School of Control Science and Engineering, Shandong University, Jinan 250061, China;

2. National Key Laboratory of Advanced Composites, Beijing Institute of Aeronautical Materials, Beijing 100095, China;

3. Key Laboratory for Liquid-Solid Structural Evolution &

Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China) Abstract: On the basis of the numerical simulation and analysis on the curing induced deformation of carbon fiber reinforced resin matrix composites, self-designed fiber Bragg grating (FBG) sensors were embedded in the composite to monitor the temperature and strain evolution during the curing process. The stacking sequence was [011/9011].The FBG temperature and strain sensors were embedded in the typical positions of the laminate along 0° and 45° directions, respectively. The composite laminate was molded by hot pressing method, which underwent two continuously cooling stages after molded. The real-time record of the FBG sensors'

central wavelength changes during the curing process shows that the absolute value of the composite material compression strain at the first cooling stage is obviously less than the one at the second cooling stage under the same temperature conditions. The difference indicates that at the first cooling stage the composite laminate is still proceeding the post curing reaction, which can be detected by FBG sensors. Besides, the monitoring data match well with the finite element simulation. Therefore, embedded FBG sensors can be used to monitor the curing process of composite materials, which provide a reliable and effective method for analyzing the curing characteristics of the composite materials. Keywords: composite materials;

curing induced deformation;

fiber Bragg grating;

process monitoring;

finite element simulation 碳纤维增强树脂基复合材料具有优异的比强度、比刚度、抗疲劳性能和良好的可设计性[1],在航空航天、汽车、建筑等领域得到广泛应用.然而,在复合材料固化成型过程中,由于材料热胀或者热缩效应、树脂基体的化学收缩效应、复合材料与模具之间的相互作用等因素的协同影响[2],往往在复合材料内部产生复杂的应力,导致脱模后的复合材料发生固化变形现象,严重影响了材料性能.因此,监测复合材料固化特性、分析固化温度和内应力演变过程,具有重要的科学意义和工程应用价值. 光纤Bragg光栅(fiber Bragg grating, FBG)因其体积小、反应灵敏、抗电磁干扰能力强、与纤维复合材料兼容性好等特性而被越来越多地应用于复合材料固化过程的监测.国内外人员研究了利用FBG传感器监测复合材料固化的技术方法.其中,Parlevliet等人[3]用内埋的FBG传感器监测了树脂的固化收缩和后固化对固化残余应力的影响.贾子光等人[4]应用自行封装的FBG传感器监测了碳纤维复合材料固化过程中温度变化和收缩应变.秦伟等人[5]和田恒等人[6]通过内埋的FBG传感器分别实现了RTM成型工艺和热压罐成型工艺中的复合材料固化过程及残余应变的监测.一些学者采用FBG传感器监测不同固化工艺下复合材料残余应力的发展历程,从而提出减小残余应力的有效方法[7-9].李雪芹等人[10]利用FBG传感器在监测树脂固化的基础上测得了固化后树脂在冷却阶段的热膨胀系数.刘刚等人[11]研究了光栅的埋植数量对层压板拉伸和压缩性能的影响.上述研究取得了良好的结果,验证了利用FBG传感器监测复合材料固化过程的可行性.但是大多数的研究工作监测了固化后复合材料内部残余应变的数值,未对复合材料的后固化特性进行深入分析. 本文在复合材料固化变形的有限元模拟基础上,设计FBG传感器的埋入工艺方法,采用热模压方式固化成型复合材料,并对成型后的复合材料进行连续两次降温处理,实时记录FBG传感器中心波长的变化,进而采用比较的方法分析复合材料的后固化特性.