The Effect of Creep on Time-Dependent Response of Aluminium Frame Structures

This paper presents the parametric study of a simple aluminium frame made of EN 6082 T6 aluminium alloy exposed to transient heating. The heating rates up to 5 degrees C/min were used in numerical calculations to simulate fire protection essential in modern structures. The main focus of the study was to determine the influence of creep strain on the reduction of the load-bearing capacity of the main columns in a typical structure. A significant impact of creep strain on the critical temperature and failure time is given with a total of 60 numerical simulations with the comparison between creep and the creep-free model. The results have shown that for the applied creep model, the failure of the column due to buckling was accelerated with the developed creep strain for 28% than without taking creep into account for the middle column. For faster heating rates and other specific columns, the given failure time gradually decreases but still with significant impact on the overall load-bearing capacity. Numerical calculations were carried out in ANSYS 16.2 software with the use of the Modified Time Hardening creep model whose parameters were obtained within the previous studies.