Experimental analysis of inelastic buckling of short rectangular tubes

Abstract

The paper presents results of experimental analysis of inelastic buckling of short metal columns with quadrilateral thinwalled cross-sections. Four series of samples with different material and section were tested under axial compression:
• steel square tubes with slenderness equal to 7.2, 11.4, and 17.4,
• steel rectangular tubes with slenderness equal to 7.2, 11.4, 17.5, and 40,
• aluminum alloys square tubes with slenderness equal to 7.2, 11.4, 17.5,
• aluminum alloys rectangular tubes with slenderness equal to 7.2, 11.4, 17.5, and 24.
The materials used were; steel St3SX and aluminum alloys EN AW-6101A and T6 (PA38). The critical loads and the buckling modes were determined experimentally. In all series the same values of column slenderness were applied. For the same different wall thickness was used for the samples made of the same material. All cross-sections are classified as class 1 according to the code PN-90/B-03200 and EC3. Static equilibrium paths were determined as relations between the compression load and the total contraction or between the compression load and the transverse deflections in the middle of a column. In the experiments, the development of deformation was investigated for the loading changing from zero to its critical value. Based on the conducted tests the effect of material properties and geometrical parameters on deformations and buckling modes was established. Finally, the experimental critical stresses were compared with design values.