Abstract
Light-weight design is becoming a key factor for the whole automotive industry: starting from the sport car to every economy car, the whole automotive sector has to comply with very stringent homologation rules. Less weight implies less fuel and less pollution making light-weight design a green choice that can lead to several advantages. Despite helping in fuel consumption’s reduction, a minor car-weight can be negative for performance in some fields, which have always taken advantages from the mass of the car, e.g. NVH.
This work presents a methodology to reduce weight in every panel inside a car, finding through an optimization the correct distribution of damping material coupled with the most efficient shape of the panel itself.
At first, a correct FE representation of the vibration-damping material that is usually added to car’s panel to improve NVH performance has been carried out through correlation with experimental analysis.
As a second step, a topography optimization has been used to find the correct design of the beads, reducing the mobility of the panel and, as a consequence, allowing the use of less vibration-damping material. At this stage the presence of vibration-damping material has been considered during the FE calculation only with a higher structural damping. During the following FE analysis, the damping material has been introduced to oppose to the first normal modes of the structure. This approach has led to a reduction in the presence of damping material with a corresponding minor weight of the structure.
At a later stage, the methodology has been improved to make a larger use of optimization. In fact, different optimization techniques have been finally used to find the correct distribution of vibration-damping material on the panel, together with the optimal shape of beads and thickness of the panel. The objective was to reduce weight maintaining the same performance in terms of mobility of the reference panel, which are required to guarantee the standards as provided in Ferrari internal regulations.
Using an optimization approach instead of the one presented before, where the beads of the panel are optimized without the presence of the damping material and the damping material is applied afterwards during FE analysis, has allowed to reduce the weight of the whole structure in analysis, i.e. panel and damping material, by more than 50%.
The proposed methodology can be potentially applied to every panel inside the vehicle helping to realize a more efficient light-weight design.
Keywords - NVH, optimization, weight reduction, vibration-damping material