An experiment on elastically compressed frusta

It is postulated that pre-buckling elastic stress pattern in axially compressed right frustum will determine its initial and progressive buckling mode. The elastic stress profiles along the generator and around various diameters of aluminium alloy frustum under axial compression were measured under different boundary constraints. The shape of such profiles was found to be periodic and wavy with relatively high peaks and high stress gradients at a number of points. It is thought that these peaks correspond to the number of lobes in multi-lobe collapse modes, which are observed when the axial loading exceeds the elastic range. These peaks are attributed to all possible imperfections in geometry and dimensions such as variations in thickness, symmetry, generator length and deviation of the axis from being perpendicular to the cross-section. (C) 1999 Elsevier Science Ltd. All rights reserved.