Finite Element Analysis of the Mechanical Behavior of Multibolted Joints Subjected to Shear Loads

When subjected to external forces, bolted joints behave in a complex manner especially in the case of the joints being clamped with multiple bolts. Friction type joints are widely used for the joints subjected to shear loads. Bearing type joints, which support the shear loads on the bolt cylindrical surface, are used less frequently, since its mechanical behavior is too complicated to accurately estimate the load capacity. In this study, mechanical behavior of the bearing type multibolted joints subjected to shear loads is analyzed by three-dimensional (3D) FEM. As a result of comprehensive calculations, it has been found that the shear load applied to bearing type joints distributes with a concave shape along the load direction, and a fair amount of the shear load is supported by friction forces as in the case of friction type joints. In addition, a simple method that calculates the shear load distribution using elementary theory of solid mechanics is proposed, which can estimate the shear load distribution with sufficient accuracy especially for the case of small friction coefficient.