Abstract This paper presents an experimental study on the loosening behaviour of threaded fasteners under cyclic shear displacement. The effects of the initial preload and the amplitude of the shear displacement on the loosening behaviour of the common zinc-coated bolts are investigated. Diamond-like carbon (DLC) coating is utilised to treat the surface of bolts for improving the wear resistance of threads. The thread damage is analysed after the tests. Results show that fatigue wear is the major wear mechanism on the first thread surface. The looseness of threaded fasteners is small under high initial preload and low amplitude of shear displacement. For DLC-coated bolts, the thread damage is slight, and DLC-coated bolts have a better anti-loosening property comparing with zinc-coated bolts.

中文翻译：

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螺纹紧固件在循环剪切位移下的松动行为

摘要 本文对螺纹紧固件在循环剪切位移下的松动行为进行了实验研究。研究了初始预紧力和剪切位移幅度对普通镀锌螺栓松动行为的影响。类金刚石碳（DLC）涂层用于处理螺栓表面，以提高螺纹的耐磨性。测试后分析螺纹损坏情况。结果表明疲劳磨损是第一螺纹表面的主要磨损机制。在高初始预紧力和低剪切位移幅值下，螺纹紧固件的松动较小。对于DLC涂层螺栓，螺纹损伤轻微，与镀锌螺栓相比，DLC涂层螺栓具有更好的抗松性能。