Hail impact damage modelling of polymeric core aluminium sandwich panels

Abstract

Aluminium sandwich panels (ASPs) with polymeric core made up of aluminium face sheets and a polymer-mineral composite core present a more cost-effective solution to building claddings than aluminium alloy because of improved energy efficiency. However, there are uncertainties regarding their resistance to impact by hail. Massive economic losses can be incurred should there be widespread damage resulted from the resistant capacity being exceeded in a hailstorm. This study investigates the resistance of such sandwich cladding panels to hail impact and the damage mechanism. Dynamic tests were conducted in this study by accelerating laboratory-made ice balls of varying sizes and velocities onto the cladding specimens at full scale. An optical 3D scanner was employed to survey indentation distribution at the dented region. Energy absorption of each layer was determined. Knowledge gained from the survey was used to develop an analytical expression for predicting the amount of permanent indentation into ASPs when struck by hail. Images captured by the high-speed camera were used to study the geometric evolution of ice spheres upon impact, with their unique characteristics incorporated into the analytical modelling process to provide a more precise analysis of the contact mechanics. The analytical predictions are shown to match with experimental measurements with discrepancy of within 10%. The presented experimental results along with the newly developed analytical model provide useful insights into the impact resistance of sandwich cladding products for guiding its design to withstand extreme weather conditions.