基于模量/应变波耦合特性的FBG碳纤维增强塑料复合材料拉伸断裂监测

FBG fracture monitoring for CFRP based on coupling characteristic of modulus/strain wave

  • 摘要: 从光纤Bragg光栅(FBG)反射中心波长随碳纤维增强塑料复合材料(CFRP)拉伸试件表面应变变化敏感特性的角度,详细研究了拉伸过程中FBG中心波长的拉伸变化速率(即CFRP的宏观弹性模量)与复合材料内部断裂饱和状态的相关性和断裂瞬间试件表面的应变波响应特性,即:在拉伸过程中,CFRP拉伸试件的宏观弹性模量随着内部断裂的发生而不断减小,且在试件出现明显应力松弛状态前趋于平稳;应力松弛状态出现时,断裂区域表面接收的应变波响应略大于其他区域。通过设计相应排布形式,将FBG与CFRP断裂监测相结合,提出了一种基于FBG传感的CFRP断裂分阶段监测方法。该方法中传感探头直接与CFRP试件耦合,测量及传导光路全光纤化,可实现对CFRP断裂状态的绝对监测。

     

    Abstract: From the sensitivity of the fibre Bragg grating (FBG) center wavelength changing with strain changes on the surface of carbon fibre reinforced plastics (CFRP) composite, the correlation between the tensile rate of the FBG wavelength and the fracture status was investigated during the stretching process and the strain wave response characteristics of the specimen surface, that is, the elastic modulus of CFRP tensile specimens decreases with the increasing of the internal damage, and stabilizes before the appearance of the stress relaxation in the specimen, at which the strain response of acoustic emission received on the surface of the fracture area is slightly greater than the one in other areas. By combining FBG with the CFRP fracture monitoring, a CFRP fracture monitoring method based on the FBG has been proposed. The method coupling sensing probe directly with specimen has achieved the absolute monitoring of CFRP fracture state.

     

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