Deformation and Slippage Modeling for Investigating Bolt Loosening Under Harmonic Transverse Excitation

This paper presents an analytical model for deformation and self-loosening performance of a preloaded M12 threaded fastener under cyclic transverse excitation based on the calibration of the bending stiffness parameters at bolt ends using finite element method. The model describes the bolt bending deflection and the relative bending rotational angle between the male and female threads, the loosening (rotational) angle, and the local contact slippage behavior of bolted joints. The analytical results for the deformation behavior of the bolt including bending deflection and bending angle are compared with the corresponding finite element results to validate the mathematical model of the threaded bolt. The shear force-displacement response, and the clamp load decay with the number of cycles are compared with the experimental data for model validation.