Energy scattering of hybrid FE-SEA model with nonlinear joints

Nonlinearity in structures causes energy scattering between different frequency ranges. This paper proposes a new hybrid FE-SEA formulation to analyse complex structures with nonlinear deterministic components. The formulation is derived in two stages. First the governing equation for deterministic components in time domain is transformed to frequency domain using the method of harmonic balance and the Galerkin method. Equivalent stiffness method is then applied in frequency domain to linearise the nonlinear terms. The second process is regarded to the derivation of the hybrid model. Based on a proposed nonlinear energy transfer model and the linearisation in the first stage, the linearised hybrid FE-SEA governing equation is derived, and the iterative procedure is given. For validation purpose, nonlinear Lagrange-Rayleigh-Ritz method plus Monte Carlo simulation is used as the benchmark model. Two case studies are applied for validation and investigation of the coupling loss factor (CLF). The coupling between subsystems at different frequencies can be reflected by the CLF. Good agreements between the benchmark model and proposed hybrid model can be observed.