Search Results

Since interior noise has a strong effect on vehicle salability, it is particularly important to be able to estimate noise levels accurately by means of simulation at 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 reducting vibration and noise of the structural-acoustic systems. The present work focused 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, the orthogonality and normalization conditions of a coupled system were derived by us. In this paper, our sensitivity analysis methods are applied to an interior noise problem of a cabin model.

The occurrence of various vibrations and noises in an automobile, such as idling vibration, boom noise and road noise, is greatly affected by the natural vibration modes and could be developed for controlling the body strength and weight these problems could be solved and a high-performance vehicle realised. This paper presents an analytical method developed by the authors to solve these problems and gives examples of its application. In developing this method, the problems of natural vibration mode and static stiffness control were addressed. Perturbation and sensitivity analysis methods have already been proposed for mode control. Four typical methods were examined and the best one was chosen in terms of accuracy and calculation time when handling large-scale problems. For static sensitivity analysis, we proposed a nevi method which is like natural mode sensitivity analysis.