Nonlinear vibration mechanism and modeling for flange-bolted joints

Nonlinear modeling of bolted joints is an extremely challenging task in structural dynamics. Considering the contact nonlinearity of joint interfaces, this study presents a new nonlinear dynamic model for flange-bolted joints. Firstly, the elastostatic properties of the flange are studied through finite element (FE) analysis. It is found that the axial stiffness shows significant differences under tension and compression, and the flange exhibits axial deformation under bending loads. Subsequently, through modeling the vibration mechanism of the axial and bending behavior of the flange, the longitudinal coupled vibrations subjected to bending impacts are analytically predicted. Meanwhile, the relevant nonlinear dynamic model for the flange is further developed, which reveals the mapping relations between the vibration properties and the preload performances. Finally, an experimental investigation is performed to validate the presented model.