钢结构角焊缝低温抗剪疲劳性能的试验研究

国内外学者对钢结构的焊缝连接在常温下的疲劳性能进行了广泛的研究，但是所见文献中对构造细节在低温下的疲劳性能研究较少。为此，以Q345B钢材制作了原状处理的侧面和正面角焊缝连接的两组板材试样，采用高频疲劳试验机在0℃、-20℃、-40℃下进行低温疲劳试验，并进行数据拟合。试验结果发现：对于侧面角焊缝试样而言，低温会提高构造细节的疲劳寿命，而低温对正面角焊缝试样的影响并不明显。低温下的正面角焊缝抗疲劳强度高于侧面角焊缝。正面角焊缝疲劳破坏形式为贯通焊缝裂纹，侧面角焊缝为焊趾向热影响区延伸裂纹。研究结果表明：低温对于不同的构造细节形式的节点疲劳寿命的影响没有统一的结论，有待更多试验进行研究并分析。

EXPERIMENTAL STUDY ON THE SHEAR FATIGUE BEHAVIOR OF STEEL STRUCTURE FILLET WELDS AT LOW TEMPERATURE

Although the research on the fatigue properties of welds at room temperature was conducted widely by scholars worldwide, little study on the fatigue properties at low temperature has been done. A number of fatigue tests were conducted by a high-frequency fatigue machine at temperatures of 0 ℃, 20 ℃ and 40 ℃. During the tests, side fillet welded and front fillet welded specimens were used. The test results show that the fatigue lives of the side fillet welded specimens increased with decreasing temperatures. However, the temperature did not have a significant influence on the fatigue lives of the front welded specimens. The fatigue performance of the front fillet welds was better than the side fillet welds. The fatigue failure cracks of the front fillet welds were through the weld. Meanwhile, the cracks of side fillet welds extended from the weld toe to the heat affected zone. The results show that the effect of the low temperature on the fatigue lives of different structural details does not have a uniform conclusion and needs further experimental analysis.