Elastostatic properties for flange-bolted joints

An accurate understanding of the elastostatic properties for flange-bolted joints is crucial in modeling the nonlinear dynamics. In this study, the elastostatics of the flange are investigated through finite element (FE) analysis and experimental test. It is shown that the axial stiffness exhibits bi-linear properties, and the flange appears axial-flexural coupling deformations under bending moments. Then, to understand the bi-linear axial stiffness properties and the influence of bolt preloads on axial and bending stiffnesses, the bolted T-stub joint is chosen as the object of study, and the relevant mechanical model is further presented based on linear elasticity. Meanwhile, the validity of the mechanical model is numerically verified. The analysis indicates that under tension and compression, the essence of the bi-linear axial stiffness is the differences in interface contact status, and the coupling deformations are induced by different tensile and compressive stiffnesses. In addition, both the tensile and bending stiffnesses increase with the increase of bolt preloads, while the effect of preloads on compressive stiffness is insignificant.