Analysis of the response of nonlinear structures with two degrees of freedom solicited by random excitation sources

In nuclear power plants, many mechanical components are held by supports which can expand freely. In the event of seismic stress, under the effect of the impacts generated, these supports induce highly non-linear effects. To analyze this type of problem, linearization methods are the most suitable. However, the nonlinear spectral behavior is not correctly represented by the Gaussian stochastic linearization. It is in this context that linearization methods with random coefficients have been developed. These techniques, very powerful in dimension one, require improvements in higher dimension. In this perspective, a study of the dynamics of a system with two degrees of freedom is conducted in the presence of shocks. A detailed analysis of the phase space reveals stable periodic regimes, which allow the construction of better equivalent linear models