Weight Optimization of Large Scale Sandwich Structures with Acoustic and Mechanical Constraints

Abstract

A generic model of a railway car body in sandwich design was weight optimized subject to various constraints. These constraints were global natural frequency constraints, buckling and wrinkling constraints, and sound reduction constraints. A finite element model was used for global analysis, while sandwich plate theory was used for local structural analyses. The acoustic model for sound reduction was a sandwich plate model. The optimization procedure started with an infeasible initial design and produced a final design which fulfilled all requirements, yet had a reduced weight. The optimization was performed with and without acoustic constraints and the results imply that the acoustic requirements will produce a heavier design than when the optimization is performed with mechanical constraints only.