Accurate Finite Element Modeling of Bolted Joints and Modified IWAN Model

Abstract

AbstractA three-dimensional finite element model of helical bolted joints is established in this paper, and the validity of the model establishment scheme is verified by a numerical examples of “the stress distribution on the bolted joint”. Then, Hysteresis curves of the resultant torque versus the applied torsion angle are obtained from the finite element analysis. The results indicate that: (1) The contact threads have experienced three states of adhesion, partial slip and macro slip during the tightening and loosening process; (2) In the state of macro sliding, the resultant torque exhibits an upward trend due to the increase of the clamping pressure in tightening process. On the contrary, the resultant torque exhibits a downward trend due to the decrease of the clamping pressure in the loosening process. A modified IWAN model is established for the three-dimensional helical bolted joint under torsional load by adding the residual stiffness and correction of torque based on the results of finite element analysis. The results of the modified IWAN model for the M12 bolted joint present that the modified IWAN model can reproduce the hysteresis curves obtained by finite element analysis accurately, and the modified IWAN model composed of three Jenkins elements can cover the dissipated energy precisely.