Structural Analysis of Compression Deformation and Failure of Aluminum in Fire

Abstract

This paper presents a finite-element (FE) modeling approach to predict the deformation, softening, and failure of compression-loaded aluminum structures exposed to fire. A fully coupled thermal-mechanical FE model is outlined. The FE model can analyze the thermal profile and deformation as well as the initial and final plastic collapse of aluminum structures in fire. It calculates the temperature profile of an aluminum structure exposed to unsteady-state heating conditions representative of fire. Using the temperature profile, the elastic and plastic deformations together with the loss in the compression load capacity of an aluminum structure caused by elastic softening, time-independent plastic (yield) softening, and time-dependent plastic (creep) softening effects are analyzed by using a mechanics-based FE solution. The modeling approach is validated by structural tests on an aluminum alloy (5083 Al) plate supporting an applied compression load while locally heated at different radiant heat flux (temperature) levels. The modeling approach can estimate the deformations, initiation of plastic collapse, and final failure of the aluminum test article for heat flux levels representative of different fire types. The FE model described in this paper can be used as the basis for performing complex deformation and failure analysis of compression-loaded aluminum (and other metallic) structures in fire.