基于电阻信号的CFRP纤维断裂识别实验及理论模型

Experiment and Theoretical Model to Identification of the Fiber Rupture of CFRP Based on Electric Resistance Signals

碳纤维是决定CFRP复合材料性能的主要因素之一,因此为保证复合材料结构的健康状态、识别纤维的损伤与断裂就显得至为关键。文中通过加载电流并采集电阻信号的方式来识别CFRP复合材料中碳纤维的健康状态,通过实验和理论分析的方法进行了深入研究。实验针对2种不同铺层的试件进行测量:单向层合板[0]8和正交层合板[0/90]4。对试件端部进行了粘接铜箔处理以使试件稳定导电,使用KEITULEY2700数据采集仪测量试件电阻。实验内容包括静态电阻测量、拉伸受力状态下材料的电阻特性分析,并建立和推导了电阻-应变理论分析模型,进行了通电疲劳实验。研究结果表明,碳纤维的铺层角度对CFRP结构电阻有较大影响,[0]8铺层材料电导率和破坏强度约为[0/90]4铺层材料的2倍;CFRP材料受外载荷作用时,损伤程度与其电阻变化有对应的关系,其电阻信号变化可以作为反映材料损伤情况和识别纤维断裂的主要参数;实验结果与所建立的电阻-应变模型拟合结果吻合较好。文中研究的CFRP纤维断裂识别和航空复合材料结构健康监控及实时监测具有重要的意义。

e main properties of carbon fiber reinforced polymer composites （CFRPs） are mainly decided by carbon fibers, so it is very important to identify the damage state and rupture condition of carbon fibers. The present paper mainly focused on the experiments and analysis model in details of CFRPs by injecting micro electric current and simultaneously collecting the electric resistance signals to identify the health state of carbon fibers. In order to investigate the electric resistance characteristics of the CFRP, two different types of specimens [0]8 and [0/90]4 were made. The ends of each specimen were bonded with copper plates which is helpful to the stability of electric conductivity. The electric resistance of specimens was measured by KEITULEY2700 DMMS. Experiment contents include static resistance measurement; the resistance of the material under tensile stress, the resistance strain model was established for CFRPs and the electrical fatigue tests. The results show that the angle of layers has a great influence on the electrical resistance. The average electric conductivity of the [0]8 is about 2 times of that of [0/90]4, when CFRPs are affected by external forces or loading, the damage of materials has a great relevance to its resistance change. The electrical resistance change as a damage parameter of tensile damage was investigated, and the experiment result and the resistance -strain model proposed show very similar trend of change. The results of this research may have very important significance to the health monitoring and real time detecting of fiber rupture foe aeronautical composite structures.