Radiation Efficiency of Engine Structures, Analyzed by Holographic Interferometry and Boundary Element Calculation

In order to control engine noises, it is necessary to know the relation between the structural vibrations and the radiation sound power. This relation is described in the radiation efficiency.

This paper reports a newly developed method which predicts the radiation efficiency. This method is composed of the new techniques. One is the vibration measurement using Holographic Interferometry by a double pulse laser and the other is the Boundary Element Calculation of the sound wave equation. Since this method only requires a simple vibration test, it is possible to accurately and quickly estimate acoustic characteristics in order to develop new products.

This method was applied to the development of a low noise engine head cover.