Finite element simulation of a laboratory reception plate for structure-borne sound power measurements

Structure-borne power from machinery into a heavyweight structure can be characterised using the laboratory reception plate method described in EN 15657-1. When designing a new reception plate for a specific kind of machinery it is potentially useful to have a prediction model to assess its dynamic behaviour before it is built. This paper concerns the development and validation of Finite Element Models (FEM) for a concrete reception plate installed horizontally on resiliently supports. Two FEM models were considered: an idealised model for an isolated plate with free boundary conditions, and a more detailed model for the reception plate in the laboratory at Stuttgart which incorporates the viscoelastic material around the boundaries which is used to increase the damping. Experimental Modal Analysis (EMA) was carried out to validate the FEM models. The degree of correlation between mode shapes derived from the numerical model and EMA was assessed using the Modal Assurance Criterion (MAC). For the first 13 modes, high MAC values and close agreement in eigenfrequencies was achieved with the more detailed FEM model. The direct injected power and the reception plate power were compared for both FEM models to assess errors for single excitation points on the reception plate