Analysis of large scale cladding sandwich panels composed of GFRP skins and ribs and polyurethane foam core

This paper addresses the numerical modeling of lightweight sandwich panels intended for cladding of buildings. The proposed sandwich panels are composed of woven glass fiber reinforced polymer (GFRP) skins and ribs and soft polyurethane foam core, which provides excellent insulation. The panels are designed to resist wind loading. A robust 3D FE model was developed for the large scale panels (9145×2440×78 mm3) tested under transverse loading. The model accounts for material nonlinearities; most pronounced in the soft polyurethane core and in the [0/90] GFRP ribs under shear, as well as geometric nonlinearities in the form of a reduction in panel thickness due to the soft core. The model captures both stability and material failure modes, essentially skin wrinkling and crushing in compression. It was then successfully validated using experimental results. Failure of the tension skin never occurred in this type of panels as compression skin wrinkling and crushing consistently governed. The cladding panel was shown to satisfy design code requirements in terms of strength and stiffness.