On the nonuniform deformation of the cylinder compression test

A theoretical model based on Hill's general method is developed in the present study to calculate the flow stress in a cylindrical specimen under axial compression in the presence of friction at the dip-specimen interface. Unlike most of the published methods which studied the incipient barreling only, the proposed theoretical model takes the barreled shape of the deforming specimen into account. In order to construct the stress-strain curve, the mean effective strain of the barreled specimen was also calculated on the basis of an assumed velocity field. As the present study shows, the proposed theoretical model provides good results, both in magnitude and in trend, for the prediction of flow stresses in the barreled specimen during the compression rest. [S0094-4289(00)00602-2].