On the fire resistance of aluminium alloy structures

摘要

The paper focuses on the importance of refined material modelling of aluminium alloys under high temperatures for correctly estimating the fire resistance of structures. In fact for such structural materials, the evaluation of the bearing capacity of structures, in general, cannot leave apart the proper modelling of the stress-strain relationship, strongly characterized by the material hardening and ductility. Therefore, firstly the effects of high temperatures are investigated at the material level, with reference to the single mechanical properties and then to the stress-strain relationship of the studied aluminium alloys for structural uses. Accordingly, a mechanical model, defined by tailoring the general Ramberg-Osgood formulation, taking appropriately into account the peculiarities of such materials at high temperatures, is provided. The proposed model is introduced in a finite element program for the analysis of structures under fire. Results are presented for a simple portal frame designed for several aluminium alloys.