AN INNOVATIVE FEA METHODOLOGY FOR MODELING FASTENERS

MacArthur L. Stewart

Abstract: Abstract –Researchers have developed finite element analysis (FEA) modeling methods to simulate the mechanical behavior of bolts in bolted joints. The most commonly used FEA bolt modeling methods are the spider and solid bolt models. The spider bolt model uses 1D elements to simulate the bolt’s mechanical behavior. This approach is computationally efficient but does not consider contact at the fastener-joint interface. However, contact at the fastener-joint interface is considered in the solid bolt model which uses 3D finite elements to discretize the geometry of the bolt, which increases the computational expense of the FEA model. In this work, an innovative FEA bolt modeling method is presented that is both computationally efficient and considers the actual geometry of the fasteners. Specifically, commercially available FEA software was used to construct a structural model of a clevis type bracket that was bolted to a rigid wall to simulate bolt pretension and the bracket’s response to an externally applied axial force. Mating surface contact was considered and the actual geometry of the fastener was modeled as force controlled rigid surfaces. The predicted contact stress at the bolt-joint interface, after bolt pretension was simulated, correlated with the analytically calculated surface pressure to within 13.5 %. After the external axial force was applied, the predicted maximum bending stress at the top and bottom of the section of interest correlated with the analytically calculated values to within 5.2 % and 8.8 %, respectively. Further investigation (experimental) is planned to study the contact stress distribution over the mating part contact areas

Keywords: bolted joint, machine component design, bolt FEA

DOI: https://doi.org/10.15623/ijret.2015.0407072