Optimization of geometrical parameters for a supporting structure with two installed coherent machines

Abstract

It is common to have two or more vibratory machines of the same type mounted on the same supporting structure. These vibratory machines transmit structure-borne sound to adjacent walls or floors and the structure-borne sound is eventually emitted as noise into indoor spaces. The interactions of the mounting points among coherent machines increase the structure-borne sound power transmission significantly at some frequencies and decrease it considerably at some other frequencies. However, there is still no general design frameworks of supporting structure optimization strategy that target on minimizing structure-borne sound power transmission by utilizing the interactions of the mounting points among coherent machines properly. This paper for the first time develops a practical design framework to obtain an optimal set of geometrical parameters for a supporting structure by using a genetic algorithm with parametric finite element models. A steel-made supporting structure with two coherent fans installed on were analyzed. Experiments were conducted to obtain the source mobilities and free velocities of the coherent fans that are required for the calculation of structure-borne sound power transmission. Parametric finite element analysis was conducted to obtain the receiver mobility of the supporting structure. A genetic algorithm solved the optimal solution. The results shown that the proposed approach is sufficiently capable of minimizing the structure-borne sound power transmission on a supporting structure with coherent machines mounted on a supporting structure.