A Transient Hybrid FE-SEA Method

The hybrid approach coupling Statistical Energy Analysis (SEA) and the finite element method has become a prominent technique for analysing structures under steady-state loads in the mid-frequency range where some components behave in a deterministic manner with low modal density and others in a statistical manner with high modal density. In this paper, the method is extended from its current steady-state capability to provide calculation of a structural response under impulsive and time-varying loads. Similar to the steady-state method, a system is split into components with low modal density that are modelled using the finite element approach and statistical components with high modal density that are modelled as SEA subsystems. An evolutionary spectrum approach based on the Priestley description of random processes is applied to model the response of both the SEA and deterministic components which are coupled by considering a power balance between the subsystems and using an amended form of the diffuse field reciprocity relation that accounts for the build-up of a reverberant field following an impulse. Results from the method are compared against finite element simulations for systems involving coupled plates and provide strong validation.