In-Plane Torsion Testing of Sheet Metal

Abstract

In this paper, the ‘in-plane’ torsion testing of sheet metal is examined. The test itself was first proposed by Marciniak in order to ascertain the work hardening behaviour and fracture strain of sheet metals. In the original work, the analysis was based on the assumption that the material was rigid-work hardening. The present work attempts a more rigorous solution, assuming the material to be elastic-work hardening. A finite-element approximation is employed to calculate the stress and strain distribution across the sheet metal annulus at various stages in the deformation process. A comparison is made between the results from the finite-element method and those based on a rigid-work hardening material. For certain annulus geometries, excellent agreement is obtained between both sets of results.