Abstract
Damping material is usually applied on the steel panel of a vehicle to reduce vibration level. On the other hand, the weight reduction is also required to improve fuel consumption. Therefore, the modal loss factor induced by damping material on the steel panel of a vehicle body sturucture needs to be maximized with a given volume. In this paper we propose a practical design method to maximize the modal loss factor by optimizing the material distribution of damping material under a volume constraint. The modal loss factor of an eigen mode can be written as the ratio of the strain energy stored in the damping material over the total strain energy in the system under consideration. In the proposed method, we assume the eigenvectors are almost the same as the eigenvectors when the damping material is removed. The modal loss factor can then be represented by using a corresponding eigenvalue where the mass density of the damping material is ignored whereas the stiffness is taken into account. Several numerical examples are provided to show the optimal distribution of the damping material by using a flat panel. Damping material is basically distributed in the domain where the strain energy is stored, which agress well with our experiences.
