Development of New Mode-Superposition Technique for Truncating the Lower and/or Higher Frequency Modes. 5th Report. Accuracy Confirmation of the New Method for the Vehicle Model and the Investigation of the Utilization Method for Vehicle Interior Noise Reduction Design.

Abstract

Since interior noise has a strong effect on vehicle salability, it is particularly importart to be able to estimate noise levels accurately by means of simulation in the design stage. The use of sensitivity analysis makes it easy to determine how the analytical model should be modified or the structure optimized for the purpose of reducing vibration and noise of the structural-acoustic systems. The present work focuses on a structural-acoustic coupling problem. As the coefficient matrices of a coupled structural-acoustic system are not symmetrical, the conventional orthogonality conditions obtained in structural dynamics generally do not hold true for the coupled system. To overcome this problem, we derived the orthogonality and normalization conditions of a coupled system. In this paper, our sensitivity analysis methods are applied to the interior noise problem of a vehicle cabin model. It will be shown how a sensitivity analysisprocess is performed, and how vibration and noise can be reduced.