Circumferential strain concentration in axial crushing of cylindrical and square tubes with corrugated surfaces

In this paper, the circumferential strain concentrations in cylindrical and square tubes with corrugated surfaces subjected to axial compression are studied using the finite element method. In cylindrical tubes, the yield strength ay, the hardening coefficient E-h of the material and the thickness t of the tube wall exert only a small influence on the strain concentration, so that the maximum circumferential strain can be approximately evaluated as a function of the wavelength 2 lambda and the amplitude a of the corrugations, and the cylinder radius R. For square tubes, however, the effect of the corner radius r, the thickness t, the yield strength sigma(y), and the hardening coefficient Eh on the strain concentration is comparable to that of the wavelength 2 lambda and the amplitude a of the corrugations. The maximum circumferential strain increases with a decrease in the corner radius r/D, with a decrease in the thickness t, and with an increase in the ratio sigma(y)/E-h. (c) 2008 Elsevier Ltd. All rights reserved.