钢结构桥梁低合金钢焊缝疲劳裂纹扩展研究

Research on fatigue crack propagation of low alloy steel welds in steel structure bridges

钢结构桥梁在焊缝金属区域初生缺陷和疲劳荷载共同作用下,会产生裂纹并快速扩展,进而降低其使用寿命。研究钢结构桥梁低合金钢焊缝缺陷的扩展规律和裂纹扩展速率,对检测结构安全性至关重要。因此研究钢结构桥梁低合金钢焊接疲劳裂纹扩展规律和速率。首先采用有限元方法将表面裂纹的形态进行数值模拟,计算疲劳裂纹形态的变化趋势。然后从钢结构桥梁的真实受力情况出发,结合扩展形态对低合金钢断裂朝度扩展规律进行分析。利用虚裂缝发展法对钢结构桥梁低合金钢焊接疲劳裂纹扩展速率进行计算。试验结果表明:提出的钢结构桥梁低合金钢焊接疲劳裂纹扩展分析方法,具有较高的准确性,最高时达到96%,充分满足研究要求。

Under the combined action of initial defects in the weld metal area and fatigue loads,steel structure bridges will generate cracks and rapidly expand,thereby reducing their service life.Studying the propagation law and crack propagation rate of low alloy steel weld defects in steel structure bridges is crucial for detecting structural safety.Therefore,the study aims to investigate the fatigue crack propagation law and rate of low alloy steel welding in steel structure bridges.Firstly,the finite element method is used to numerically simulate the morphology of surface cracks and calculate the trend of changes in fatigue crack morphology.Then,starting from the actual stress situation of steel structure bridges,combined with the expansion morphology,the fracture propagation law of low alloy steel is analyzed.Calculate the fatigue crack propagation rate of low alloy steel welding in steel structure bridges using the virtual crack development method.The experimental results show that the proposed method for analyzing the fatigue crack propagation of low alloy steel welding in steel structure bridges has high accuracy,reaching a maximum of 96%,fully meeting the research requirements..