Light weight structures exposed to fire: a stainless steel sandwich panel

A new type of laser-welded stainless steel sandwich panel with rock wool insulation has been developed by Kenno Tech Ltd. It is the aim of the present study, conducted in the frame of the RFCS project "Stainless Steel in Fire", to prove that a fire resistance of 30 to 60 minutes can be achieved without additional active or passive fire protection. The sandwich panel system has been tested in small and large scale fire tests to investigate the thermal and load bearing behaviour of the element exposed to fire. Furthermore, numerical models have been established. This contribution focuses on the presentation of the thermal and mechanical numerical analyses, which were performed with the general purpose FE-software packages ABAQUS/Standard and COMSOL Multiphysics. As the mechanical response of the structural element has no influence on the heating of the member, the thermal and mechanical problems could be solved separately. Thermal analyses have been performed in 2D with ABAQUS/Standard and COMSOL Multiphysics considering material nonlinearities. The results of the two programs are compared to each other and to the test results. The mechanical analysis was performed with ABAQUS/Standard using a three-dimensional shell model and considering material nonlinearities, buckling analyses and the effect of high temperatures on the structural behaviour. The results are compared to fire tests.