A profound study on the effects of friction coefficient on torque tightened longitudinally loaded, bolted connections

Friction coefficient between different surfaces of bolted connections plays an important role, since it is the most contributing factor in transferring the applied external loads. The main contribution of this paper is in a numerical study on the effects of friction coefficient on the resulting initial and final clamping force in bolted connections, before and after being loaded longitudinally. In the analysis a full, precise, (3D) finite element simulation of a bolted connection assembly, without any simplifications, was performed using the new and state of the art ANSYS package platform called ANSYS WORKBENCH. Then, the assembly was loaded with 2 tangential forces on two opposing sides of the nut's hexagonal faces, which generated a 7N.m torque around the center of the bolt, and the resulting clamping force was calculated. The results, showed that the five different counteracting surfaces of the model, each contribute to the resulting clamping force differently. The friction coefficients in nut-nut washer -as the factor which determines the proportion of the external force to be passed to other parts- and bolt head-bolt head washer –as a support which keeps the clamping force inside- regions affected the resultant clamping force more than the others.

Keywords:

friction coefficient , clamping force , bolted joint , numerical investigation , finite element modeling