Analysis on volume invariability of metal circular shaft in torsion deformation

Abstract

Volume invariability of metal circular shaft in the case of small strain torsion deformation and large strain torsion deformation was, respectively, discussed experimentally and theoretically in this study. In accordance with the elastoplastic theory, it was given that the shear stress did not cause the change of volume in the large strain range. By utilizing torsion experiment with the solid shaft of low carbon steel, it was proved that metal can meet the conditions of the volume invariability in torsion deformation while the cumulative damage was not very serious. Volumetric deformation was analyzed in torsion of circular shaft in the perspective of micromechanics. Finally, Swift effect of solid circular shaft and tubular shaft of brass material were interpreted by using the formulae of elastoplastic critic load obtained from double-limb bar model test presented by Shanley.