Plastic Deformation of Anisotropic Tubes in Hydraulic Bulging

The anisotropy of tubular material is assessed from the values of the width/thickness strain ratio determined in the tension tests. Applying Hill’s theory of plastic anisotropy, these values are incorporated in the expressions for determining the stress/strain characteristics for anisotropic material in the tension and bulge tests, and also in the theoretical analysis of the hydraulic bulging of anisotropic tubes. Experiments have been carried out on copper tubes. Taking into account the anisotropy effect, the stress/strain curves determined in the tension and bulge tests agree closely except at the low strain region. In the analysis of the bulging process, comparison is made between the theoretical and the experimental circumferential strain distribution. The results appear satisfactory.