基于力阻效应的CFRP加固钢梁的自检测技术

摘要

针对碳纤维增强塑料(CFRP)加固钢结构,基于加固材料自身的力阻功能特性,提出以覆盖在结构表面的CFRP加固层作为传感器实施结构的变形与损伤监测.开展了CFRP加固钢梁的三点弯曲实验,利用四电极法监测了加载过程中CFRP加固层的电阻响应.结果表明,在循环加载过程中,无论是位于受拉侧还是受压侧,CFRP加固层的电阻均能及时响应结构的变形,而且具有良好的线性和重复性;在单调加载至屈服阶段时,CFRP加固层的电阻响应曲线相应地出现转折点,当结构破坏时,该电阻响应曲线发生突变.实验结果为CFRP加固钢梁变形与损伤的自监测提供了依据.%Carbon-fiber reinforced plastics (CFRP) can be used to strengthen the steel structures.Based on the piezoresistivity of strengthened materials,this paper proposed a method that used CFRP reinforced layer as the sensor to monitor the deformation and damage of structures.Three-point bending tests were conducted on CFRP strengthened steel structures and four-probe method was used to monitor the resistance response of CFRP reinforced layer.The experimental results show that during the cycling loading test,the resistance of the CFRP-reinforced layer can respond to the deformation of the structure,and the response curve has good linearity and repeatability whether on the tension side or the compression side of structures.In the period of the structure's monotonous loading and yielding,the inflection point appears correspondingly in the resistance response curve of the CFRP-reinforced layer.When the structure is destroyed,the resistance response curve abruptly changes,which provides the basis for the self-monitoring of the deformation and damage of steel beams strengthened by CFRP.