Handling of acoustic constraints in multidisciplinary optimization processes

Metal sandwich panels with corrugated cores are an appealing industrial solution thanks to their high stiffness-to-mass ratio. However, such structures may suffer from poor acoustic insulation properties. Therefore, an increasing attention is being focused on combined structural-acoustic optimization to find a balance between these conflicting characteristics. Nevertheless, properly defining and handling acoustic constraints is not always straightforward and it is usually experienced-based. In this paper, an optimization process on a sandwichbased train floor component, i.e. the inner floor, is carried out to minimize its mass per unit area. First, the acoustic constraint, i.e. the weighted sound reduction index, is investigated and discussed. Secondly, different optimization methods, both gradient and non-gradient based, are used to solve the problem and the results are compared. Finally, an assessment of the various methods is given.