Optimization of Vehicle Damping Sheets Position Based on Energy Calculation 2020-01-1528
As a common means for reducing vibration and noise for automobiles, damping material is usually employed in the vehicle body, typically on the floor, the dashboard and the top roof. With the growing demand of fuel economy, light weighting, as well as NVH comfort, the optimization of the damping pads has become a topic of increasing importance. In numerical simulation, the traditional methods generally make use of the modal strain energy of the metal sheet as the main indicator for making layout choice for the damping pads. These methods are generally not able to take into account the specific location and amplitude of the structural-borne excitations, e.g. road noise or engine excitation. Therefore the optimization is not performed according the vehicle’s real working condition. Furthermore, the traditional methods do not depend on the accurate properties of the damping material. In this paper, a novel optimization method based on energy analysis is presented. This method relies on the subdivision of the vehicle body area into finite number of patches (composed of finite elements), and the energy computation of the vibration and noise indicators when a general damping property (modal damping) is applied on each patch consecutively in a loop. Such operation allows us to determine the area most sensitive to damping application under a given excitation. Subsequently, the damping pads are modeled as solid finite element and their exact material properties being applied on the chosen area. A hybrid modal-physical finite element model including the body, the cavity and the damping pads then allows to predict the noise level, reflecting the impacts of the damping material to a refined level. Optimization scripts for both position and thickness have been developed and applied on a vehicle of BAIC motor.