Modelling of corrugated core sandwich panels in multidisciplinary optimization processes

Metal sandwich panels are becoming increasingly important as multi-functional components in many industrial areas. One of the main characteristics is their high stiffness-to-mass ratio, especially under bending conditions. This property strongly depends on the two faces, but other properties – acoustic, thermal, etc. – are governed by the core. Therefore, R&D in innovative cores is justified by the effort the industry is making to create multi-functional components that integrate good performances in different fields. The multi-functionality of components can be efficiently achieved by using multidisciplinary optimization (MDO) processes. Nevertheless, given their iterative nature, quick but accurate simulations are needed to define component characteristics. In this context, the PhD activity reported in this dissertation aims at developing modelling techniques, even simplified, which allow determining the static and dynamic properties of all-metal corrugated core sandwich panels to include them in optimization processes. To begin with, an analytical formulation to represent a general corrugated core as an equivalent homogeneous layer is presented. The main limitations of already developed formulations are overcome by the proposed methodology. Moreover, given the absence in the literature of accurate formulations for sinusoidal cores, the general one is simplified to adapt it to that specific geometry. Nevertheless, it is shown that, due to manufacturing processes, the real shape of the corrugation is different from the supposed sinusoidal shape. A measurement campaign – tensile testing and modal analysis – is performed to validate the analytical formulation and to prove the importance of modelling the real shape of the corrugation, especially for the modal analysis. Finally, to show the industrial advantages of using the proposed modelling technique, a case study was investigated. An optimization process is set up on sinusoidal corrugated sandwich panels with both static and acoustic constraints applied, which would not be possible without the computational time reduction achieved by the analytical equivalent modelling proposed.