The self-loosening of bolted assemblies under cyclic transverse loading is a major issue for industrial installation, as it affects the reliability of mechanical structures. Although many studies have examined the loosening mechanism involved, the influence of joint stiffness and lateral amplitude is still not well explored in the literature. This research aims to quantify the effect of amplitude on assemblies with different stiffnesses in order to understand the self-loosening behavior for various configurations.
Tests were carried out on plates bolted with a single fastener and subjected to cyclic transverse loading with varying amplitudes (from 0.1 in to 0.35 in). Using sensors, the tests made it possible to measure preload loss, bolt and nut rotation, relative displacements, and transverse force as a function of the number of cycles. The results show a nonlinear relationship between amplitude and loosening rate, with the identification of a low amplitude range where loosening is almost negligible, while beyond a threshold a significant loss is observed. These results provide a better understanding of self-loosening mechanisms and form a basis for improving future designs and sizing of bolted joints, and allow, based on the data generated, to establish a predictive empirical equation for preload loss as a function of the number of cycles.
| Date | 11 May 2026 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Hakim A. Bouzid (Supervisor) & Anh Dung Ngô (Co-supervisor) |
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Yaya Achimou, A. (Author),
Bouzid (Supervisor) &
Ngô (Co-supervisor),
11 May 2026Student thesis: Master's thesis › Master in Engineering: Mechanical Engineering