Estimation of fatigue life of fasteners in different grades using vibration measurements
Conference paper > Summary Text · 2024
Authors: Tolga Aydın, Mahmut PEKEDİS
Hodja Akhmet Yassawi 8th International Congress on Scientific Research, Türkiye, Konya, International, Verbal, Summary Text, 2024-2024, pp 855-856
Summary
<p>The primary cause of bolt failure under operational conditions is typically fatigue-related factors, rather than the applied load exceeding the static strength limit. Even when a certain number of cold-forged bolts manufactured in the same batch are subjected to fatigue testing, the results exhibit considerable scatter. The present state of uncertainty shows a potential security risk in a number of industrial sectors, with particular implications for the safety components. The lack of a clear engineering approach to predict the scattering rate makes it difficult to identify the fatigue behaviour of a single component. For bolts with comparable properties, standardisations and engineering equations can be employed to infer the fatigue life according to the bolt type and loading condition. Conversely, the fatigue life of the bolt cannot be inferred individually during periodic maintenance on the assembly area or during the initial assembly phase. Individual fatigue tests can be performed, but the results are inevitably accompanied by bolt failure. There is currently no method or device in the literature that can predict the individual fatigue life without any damage to the bolt. In this study, the vibration measurements of bolts were processed using engineering equations in order to investigate the individual predictability of fatigue life. Within the scope of the study, vibration measurements on bolts were carried out using components such as a shaker, accelerometer and strain gage, and fatigue tests of measured bolts are performed. The relationship between the aforementioned measurements and the fatigue life cycles of the bolts was then evaluated, with particular focus on the compatibility of parameters such as natural frequency values, frequency response functions and power spectrum densities with fatigue life. Should a correlation between vibration behaviour and fatigue life be identified, the study would be of significant value not only in terms of predicting fatigue life but also in establishing a research area for the non-destructive detection of deformation defects such as folding, etc. as a quality control method.</p><p><strong>Keywords: </strong>Bolt fatigue, vibration, natural frequency, fastener.</p>