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研究了拉伸载荷下碳纤维复合材料(CFRP)T型接头的界面脱粘与裂纹扩展过程。对拉伸载荷下T型接头破坏过程进行数值模拟;在模拟敏感区域布置光纤布拉格光栅(FBG),实时监测界面脱粘的产生及扩展应变特征;使用高速摄像机,捕捉脱粘及裂纹扩展的图像数据。结果表明:T型接头的三角填料区首先出现损伤,裂纹向两个方向扩展。水平方向:向L型层与一型层之间的胶层扩展;竖直方向:向两个L型层之间的胶层扩展。裂纹扩展最终引起结构失效。光纤布拉格光栅中心波长的变化能够在非视觉条件下记录损伤的出现、积累与扩展,可正确预警结构内部损伤的产生,还原裂纹扩展路径。
The interfacial debonding and crack propagation of carbon fiber composite (CFRP) T-joints under tensile load were studied. Numerical simulation of T-joint failure process under tensile load was carried out. Fiber Bragg Grating (FBG) was placed in the sensitive area of the simulation to monitor the generation of interface debonding and extend the strain characteristics in real time. The high-speed camera was used to capture images of debonding and crack propagation data. The results show that the triangular fillet zone of the T-joint is damaged first, and the crack propagates in both directions. Horizontal direction: Expansion of the glue layer between the L-type layer and the type 1 layer; Vertical direction: Expansion of the glue layer between the two L-type layers. Crack propagation eventually causes structural failure. The change of the center wavelength of fiber Bragg grating can record the emergence, accumulation and expansion of damage in non-visual conditions, which can correctly warn the internal damage in the structure and restore the crack propagation path.