Finite element modelling of tensile deformation and failure of aluminium plate exposed to fire

• First model to predict tensile softening and failure of aluminium alloys in fire.
• Model combines thermal and mechanical effects.
• Model considers all the main softening processes of aluminium in fire.
• Validation of the model using experimental data.

This paper presents a coupled thermal–mechanical finite element model for analysing the tensile softening, deformation and failure of aluminium plate exposed to fire. The model consists of two parts: thermal analysis followed by mechanical analysis of aluminium under combined one-sided heating and axial tensile loading. The thermal analysis computes the temperature rise in the aluminium when exposed to one-sided transient radiant heating (e.g. fire simulation) and the mechanical analysis calculates the strength loss, plastic deformation (including necking) and failure of the aluminium under tensile loading. The mechanical model analyses the combined effects of elastic softening, time-independent plastic softening, time-dependent (creep) plastic softening, and thermal expansion on the tensile failure of aluminium plate. The model is validated by comparing theoretical predictions of the tensile deformation and stress rupture times against values measured from fire structural tests performed on aluminium plates. The model predicts the temperature, plastic deformation and failure with good accuracy.

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