EFFECT OF ANNEALING, SIZE AND CUTOUTS ON AXIAL COLLAPSE BEHAVIOR OF CIRCULAR TUBES

Axial compression tests were performed on round tubes of different sizes and made of aluminium and mild steel, both in as-received and annealed conditions. Length to diameter and diameter to thickness ratios of these tubes were varied in different tests, and cut-outs in the form of circular holes, varying in diameter, number and position, were laterally drilled in them. Typical histories of their deformation and load-compression curves are presented and the influence thereon of the annealing process, the tube size, or the cut-outs is discussed. Relations are presented to describe these influences and to express the first peak and mean collapse loads in terms of the Vickers hardness number. It is seen that the presence of holes in the tubes alters their mode of collapse and, as a consequence, affords the possibility of avoiding Euler buckling even when relatively much longer tubes are employed.