Investigation of influencing factors on loosening resistance for high-strength mining machinery bolts under transverse cyclic loading

This study establishes finite element models to analyze the performance of M10×1.5 bolted connections with and without fit clearance under transverse vibration loads. Numerical simulation methods are employed to investigate the variation patterns of thread root stress and preload. The results demonstrate that, under a preloading level of 0.5σ, a transverse vibration load amplitude of 0.6 mm, and a frequency of 10 Hz, the thread root stress of the M10×1.5 bolted connection with fit clearance exceeds that of the connection without clearance during three distinct cycles (0.8–0.9 s,3.8–3.9 s, and 6.8–6.9 s). However, during the 9.8–9.9 s cycle, the thread root stress of the connection with fit clearance is lower than that of the connection without clearance. Additionally, a phase difference exists between the thread root stress of the bolt and nut, leading to a more pronounced preload decay. The presence of fit clearance redistributes the stress between the threads and provides space for stress release.