Band-averaged variance prediction in hybrid finite element-statistical energy analysis

The hybrid finite element - statistical energy analysis (FE-SEA) method is a versatile framework for vibro-acoustic analysis. The stiff system components are modelled with the finite element method or another deterministic approach, while the wave fields in the flexible components are considered diffuse. In this paper, the hybrid method is extended such that not only the ensemble mean and variance of the harmonic system response can be computed, but also of the band-averaged system response. This variance represents the uncertainty that is due to the assumption of a diffuse field in the flexible components of the hybrid system. The validity of the expressions is numerically verified against a detailed Monte Carlo analysiss of a built-up plate system with random mass distribution.