In this study, the digital image correlation technique is used to determine the inconsistent mechanical properties and microstructure non-uniformity in different regions of aluminum alloy butt welded joints. A state monitoring method is proposed based on phased-array ultrasonic total focus imaging for crack evolution. A series of surface fatigue crack propagation tests on full-scale aluminum alloy butt welds are investigated, which innovatively revealed the mechanism and evolution law of crack propagation at the surface of the weld. The analytical function for dynamic crack propagation in welded structures is proposed, which provides a new idea and data support for clarifying the state deterioration process of structures. The results show that the traction structural stress can effectively identify the critical fatigue position of the weld and effectively account for the effect of angular misalignment. The phased-array ultrasonic total-focus imaging monitoring analysis method for surface fatigue crack propagation is proposed to improve the completeness of the fatigue crack evolution law.

中文翻译：

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全尺寸铝合金接头对接焊缝疲劳裂纹评估：牵引结构应力的实验和数值研究


本研究采用数字图像相关技术来确定铝合金对接焊缝不同区域力学性能不一致和微观组织不均匀性。提出一种基于相控阵超声全焦点成像的裂纹演化状态监测方法。研究了一系列全尺寸铝合金对接焊缝表面疲劳裂纹扩展试验，创新性地揭示了焊缝表面裂纹扩展的机理和演化规律。提出了焊接结构动态裂纹扩展的解析函数，为阐明结构状态恶化过程提供了新的思路和数据支持。结果表明，牵引结构应力可以有效识别焊缝的临界疲劳位置，并有效考虑角度不对中的影响。提出表面疲劳裂纹扩展相控阵超声全聚焦成像监测分析方法，提高疲劳裂纹演化规律的完备性。