Fatigue crack growth in composite, single lap bonded joints is analysed by back face distributed strain sensing, using optical backscatter reflectometry. Crack growth is inferred from the back-face strain profile measured with high spatial resolution along optical fibres bonded on the joints. The indications about the position of the crack front are compared with micro computed tomography scans conducted on specimens at suitable interruptions of the fatigue tests. By the proposed technique, crack initiation can be clearly detected, and measurements of crack growth are in good agreement with observations, with decreasing error with increasing crack length.

中文翻译：

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通过背面分布式应变传感分析复合材料粘结接头的疲劳裂纹扩展并与 X 射线显微断层扫描进行比较

使用光学背散射反射法，通过背面分布应变传感分析复合材料单搭接接合处的疲劳裂纹扩展。裂纹扩展是从沿着接合在接头上的光纤以高空间分辨率测量的背面应变分布推断出来的。将裂纹前沿位置的指示与在适当中断疲劳试验时对试样进行的显微计算机断层扫描进行比较。通过所提出的技术，可以清楚地检测裂纹萌生，并且裂纹扩展的测量值与观察结果非常一致，随着裂纹长度的增加误差减小。