Crack growth life assessment of the deep-sea manned cabin based on eddy current thermal imaging detection.

Most of the deep-sea pressure-resistant structures are made of high-strength materials. The pressure-resistant structures are made with large-thickness welding technology, which can easily result in stress concentration and cracks. In this paper, a method for crack identification and life evaluation of pressure-resistant structures based on the crack is proposed. On the one hand, the principle of eddy current thermal imaging detection is used to identify cracks. The experimental platform is built to detect cracks in pressure-resistant structures. The titanium alloy samples with micro-cracks are detected to analyze the temperature distribution and heat conduction mechanisms of surface cracks. In addition, the correlation between transient temperature changes and crack damage is investigated. On the other hand, based on the detection of micro-cracks, a fatigue crack growth model is proposed to compute the fatigue crack growth life of the pressure hull. The rationality of the eddy current thermal imaging crack detection method and life evaluation of pressure-resistant structures is verified.