Numerical analysis of stress concentration and crack initiation in a bolted joint under combined fretting loads

This study aims to predict the mechanical response of a bolted assembly composed of two aluminum alloy plates with localized damage in the contact region, under combined normal and tangential loading. A finite element model was developed using ANSYS to simulate the stress field distribution within the assembly. The analysis focuses on identifying critical stress concentrations that may initiate and propagate cracks. Nodal stress solutions were evaluated for key parameters, including von Mises equivalent stress, maximum principal stress, friction stress, and contact pressure. Results indicate that the highest stress levels occur near the nut-side interface at a specific angular and radial location (θ ≈ 181.86°, r ≈ 13.64 mm), where the tangential stress component (σₓₓ = 288.86 MPa) exceeds the material’s elastic limit (220 MPa). The findings highlight the dominant role of tangential loading in crack initiation and provide precise localization of the most vulnerable zone within the contact area. This numerical approach enhances the understanding of damage mechanisms in bolted joints subjected to fretting conditions and supports improved design strategies for structural reliability.