Design methods for high thermal efficiency load bearing inserts used in composite sandwich structures

Abstract

Composite sandwich panels with foam cores are gaining importance in the automotive industries due to their lightweight design. The panels are subjected to localized loads with the help of inserts. These load carrying inserts cause an adverse effect such as stress development, thermal losses etc., in the panels. In this thesis, a special engineering design is considered to help improve the stresses developed in the core and reduces the thermal losses in the sandwich panel. The panel is assumed to be perfectly bonded to transfer the loads. Thin face sheets with different materials such as aluminum, carbon fibre (CF) and glass fibre (GF) along with different thick foam core material such as extruded polystyrene (XPS), Polyethylene terephthalate (PET) and Polyvinyl chloride (PVC) are investigated. An analytical model to calculate the thermal conductivity across the sandwich panel with insert is developed using Fourier heat transfer law. An FE model of the sandwich panel with insert is also developed to analyze the strength and heat flux for different geometry within the panel. Finally, an optimization toolbox is developed based on the constraints and objective.