A new approach for the linearization of dynamics in bolted joints

Joints are an important source of vibration damping in built-up structures. Their mathematical modelling is, however, complex due to microslip with highly nonlinear nature. This is a major reason for developing a reduced-order model of dynamics in joints. The singular value decomposition is applied to decompose the time history and arrive at a linear model for joint dynamics while preserving the physics of the model at the same time. The model, which is a linearization of joint dynamics, is obtained by the introduction of certain functions of time which replace the nonlinear forces in the reduced space for harmonic excitation. A two-fold computational advantage is achieved by (1) increasing the size of the stable time step and (2) reducing the number of generalized coordinates substantially. Several configurations of joint, having different geometry and dynamic parameters, are studied with the help of the reduced-order model. The state of the system as well as the hysteretic behaviour is successfully modelled showing very good agreement with full model.