Analytical modeling of axial stiffness of tensile bolted joints under concentric external load

Abstract

Stiffness of bolted joints is a critical parameter for determining deformations and natural frequencies of assemblies. In this study, the effect of external load on axial stiffness of bolted joints is clarified theoretically for the first time. The stiffness of stress zones between and beyond load planes is derived on the basis of the strain energy method and used to formulate the stiffness of bolted joints. The influence of the distance between the load planes of the external load, axial positions of the external load, and difference in the material of the clamped parts on the stiffness of the bolted joints are investigated by applying the proposed formulations and finite element method. Comparisons with finite element results indicate that the proposed formulation can accurately predict the stiffness of the bolted joints.