Numerical investigation on the ultimate strength of aluminium integrally stiffened panels subjected to uniaxial compressive load

The objective of this study is to analyse numerically the ultimate strength of stiffened aluminium panels built with extruded aluminium profiles. A finite element code is used to reproduce the mechanical response of the stiffened panels subjected to axial compression. The fabrication related imperfections, such as initial deformations, material softening in Heat-Affected Zone (HAZ) and residual stresses are simulated. The numerical simulations are compared with the experimental response curves, and sensitivity to geometric parameters, initial imperfections and material properties are analysed. The results show that for the considered panel: 1) The ultimate strength is more sensitive to the cross-section dimensions than to the length; 2) The initial deformation has a strong effect not only on the level of ultimate strength but also on the failure mode as well; 3) Both the width of the HAZ and the yield strength in the HAZ has little effect on the ultimate strength of the considered aluminium integrally stiffened panels; 4) The residual stresses will improve the ultimate strength for the considered panels.