Comparative study of joint stiffness calculations using the finite element analysis

The focus of this work is on the calculation of the member stiffness of bolted joints. Three different types of joints were discussed according to the methods of loading, which are: Conventional Joints, Axisymmetric Loaded Joints and Eccentrically Loaded Joints.;Different limitations of simulating the joint connections were studied in the simple form of conventional joints. For the joints under the compressive and transvers loading the best accuracy were achieved by modeling all parts of the joints including all parts of the bolt and the interactions between them. In axisymmetric joints these issues can replace the model without any effect on the accuracy of the system.;The effect of washer in the joint connections is also studied which shows how washer can localize the effect of the compressive load in the connections without having a significant change on the stiffness of the joint.;Calculation of the load location factor is also determined in this study and the results were compared with the results reported in VDI 2230 (The German Structural Code). The calculated values from this study show the lower value compared to the VDI, due to the fact that in this study, the external load is applied on the members more realistically. In VDI the applied force is applied exactly at the bolt axis, which is not the case in real problems.;Separate simulations were performed for each of the three different types of joints. A new analytical method was introduced for studying the connections. This method takes into consideration the member stiffness reduction associated with the residual force, compression deformation caused by the external load itself and member dimension change due to the member rotation. Stiffness of the conventional joints can be calculated if the new analytical method's factors were neglected.