A Tool for the Simulation and Optimization of the Damping Material Treatment of a Car Body 2005-01-2392

The cost and weight reduction requirements in automotive applications are very important targets in the design of a new car. For this reason all the components of the vehicle should be optimized and the design of the damping material layout needs thoroughly analyzing, in order to have a good NVH performance with the minimum weight and cost. A tool for optimizing the damping material layout has been implemented and tested here - the need to explore the entire design space with a large number of variables suggested the use of a multi-objective genetic algorithm. These algorithms require a large number of calculations, and so the solution of the complete NVH model would be too expensive in terms of computational time. For this reason a new software tool has been developed, based on simulation of the damping material treatments by means of auxiliary mass and stiffness matrices added to the baseline modal base. Using this procedure, the required simulation time for each damping material layout configuration is reduced to a few minutes, by exploiting the capability of the genetic algorithm to efficiently explore the design space. As a result, some configurations with a significant weight reduction or a much better acoustic performance have been found.

Once the most effective damping areas have been identified, a second developed optimization tool is able to further refine the shape of the previously found damping patches, in order to improve the performance/cost ratio. This second procedure uses the superelement approach for the car body surrounding the panel in question, and the acoustic response is calculated by a simplified approach based on a unilateral fluid-structure coupling.