A study on buckling of thin conical frusta under axial loads

Experiments were performed wherein conical frusta of aluminium of thicknesses between 0.7 and 1.62 mm and semi-apical angles range of 16-29 degrees were axially compressed in a universal testing machine. The load-deformation curves and deformed shapes of specimens were recorded. These deformed in axisymmetric concertina mode and non-symmetric diamond modes. A three dimensional numerical simulation was carried out for all samples tested under quasi-static loading using ANSYS(R). Various stages of collapse of the shell, including non-symmetrical lobe formation were simulated for the first time, and material, geometric and contact non-linearities were incorporated. The plastic region of the material curve was assumed to be piecewise linear. Tensile tests were performed on standard samples to obtain stress-strain curves. Results thus obtained compared well with the experiments. Based on the formation of rolling and stationary plastic hinges an analysis was also carried out to study the behaviour of shells under axial compression and results were compared with experimental and numerical results. (C) 2006 Elsevier Ltd. All rights reserved.