为研究装配式钢结构用高强度螺栓的低周疲劳破坏特性及寿命规律，基于自行设计的加载装置，针对15个10.9级M24高强度螺栓进行了常幅轴心受拉低周疲劳试验，分析了在不同位移载荷下的典型高强度螺栓试样的疲劳破坏特征。另外，探讨了使用幂指函数公式与Coffin-Manson公式在预测高强度螺栓低周疲劳寿命时的适用性。结果表明：位移载荷增大使得高强度螺栓应力集中明显，断口表面变得更加粗糙，疲劳扩展区域减小，瞬断区域增大；螺栓主要破坏位置位于螺杆与螺母接触的第一级螺纹处；高强度螺栓低周疲劳寿命与循环位移幅值之间无显著单调规律，相近低周疲劳寿命可对应不同的位移载荷；当位移幅值接近极限承载强度时，螺栓的破坏状态更接近于静力拉伸破坏状态。此外，基于幂指函数公式的预测效果明显优于Coffin-Manson公式的预测效果，当δ/δy小于2.45时，预测效果更好。

To investigate the low-cycle fatigue damage characteristics and life patterns of high-strength bolts used in assembled steel structures, a low-cycle fatigue test under constant-amplitude axial tension was conducted on 15 M24 Grade 10.9 high-strength bolts using a self-designed loading apparatus. The fatigue failure characteristics of typical high-strength bolt specimens under different displacement loads were analyzed. Additionally, the applicability of the power law function and the Coffin-Manson formula for predicting the low-cycle fatigue life of high-strength bolts was explored. The result shows that increased displacement load intensifies stress concentration in high-strength bolts, resulting in rougher fracture surfaces, reduced fatigue crack propagation area, and enlarged instant fracture area. The primary failure location of the bolts is at the first thread where the bolt and nut make contact. There is no significant monotonic relationship between low-cycle fatigue life of high-strength bolts and cyclic displacement amplitude, as similar fatigue life can correspond to different displacement loads. When the displacement amplitude approaches the ultimate load-bearing capacity, the bolt failure state resembles that of a static tensile failure. Furthermore, the power law function formula predicts fatigue life more accurately than the Coffin-Manson formula, especially when δ/δy is less than 2.45.

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