A novel method of determining the crack tip location from a thermoelastic quadrature signal is presented. The method is utilised for crack tip locations within complex stress fields, namely within fastened aircraft lap joints. Coupled structural-thermal finite element modelling was undertaken to investigate the thermal response field around the crack tip location and develop the algorithmic principles. Experimental validation of the crack tip location was conducted using established crack mouth compliance techniques and optical measurements. The crack tip finding algorithm used the location of the maximum spatial gradient of the thermal field in the direction of crack growth. The method showed good accuracy when compared to traditional methods. Resultant crack growth rates were further verified using quantitative fractography.

提出了一种根据热弹性正交信号确定裂纹尖端位置的新方法。该方法用于复杂应力场内（即紧固的飞机搭接接头内）的裂纹尖端位置。采用结构-热耦合有限元建模来研究裂纹尖端位置周围的热响应场并开发算法原理。使用已建立的裂纹口顺应技术和光学测量对裂纹尖端位置进行实验验证。裂纹尖端查找算法使用裂纹扩展方向上热场最大空间梯度的位置。与传统方法相比，该方法显示出良好的准确性。使用定量断口分析进一步验证了最终的裂纹扩展速率。