Finite Element Analysis of the Load Factor and Design for Bolted T-Shape Flange Joints Consisting of Dissimilar Clamped Parts

In the present paper, the load factor for bolted T-shape flange joints where two dissimilar material (steel-aluminum) of T-shape flanges are clamped by two bolts and nuts under external tensile loadings is examined using Finite Element analysis. Furthermore, the effect of the distance C between the center of the bolt and that of T-shape flange on the load factor and a load when the interfaces start to separate are examined. In addition, the mechanical characteristics of bolted T-shape flange joints where two clamped parts are steel and aluminum are examined. The value of the load factor for steel-aluminum T-flange joint is a little bit larger than that for steel-steel T-flange joints. When the external tensile loads are applied to the bolted T-shape flange joints, the bolts are inclined and as a result, the bending moment occurs in the bolts. A maximum bending stress in the bolts is also shown and it is about 6% larger than the bolt stress due to the load factor. For verification of FEM calculations, experiments to measure the load factor and the maximum bending stress occurred in the bolts are carried out. The FEM results are in a fairly good agreement with the experimental results. Finally, based on the obtained results, a design method for bolted joints with dissimilar T-shape flanges is demonstrated for determining the nominal bolt diameter and the bolt strength grade. It is found that the contact stress at the bearing surfaces of aluminum T-flange is critical.