Evaluation of Model Uncertainty in Acoustic Response Analysis of Vehicles

With particular reference to optimum vibro-acoustic design applications, this paper discusses some of the methods available to include the effects of model parameter uncertainty in the low frequency response analysis process. The emphasis in this paper is on uncertain model parameters that are represented probabilistically. The so-called “modal correction method” in which the effects of physical structural modifications are estimated by adjustment to and rapid re-solution of the modal equations of motion, is reviewed. The accuracy of the modal correction method in the context of uncertainty analysis is discussed. The background to methods in CDH/VAO for the analysis of uncertain structures is discussed. These methods include Monte Carlo analysis, first order sensitivity (FOSM) and first order reliability analysis (FOR). An approach to stochastic optimization is discussed. Application to a representative vibro-acoustic design using several different methods is presented.