This paper describes simulation studies using the public domain versio
n of the DYNA3D hydrocode of the torsion test, which by definition is
a 3 dimensional test. The mesh resolution required to resolve the stre
ss system and the general shear deformation within the gauge length of
the specimen has been investigated. Furthermore the simulations have
been compared in detail with experiments in terms of the shear stress/
strain curve and the general strain distribution over the gauge length
under conditions of steady deformation for iron and RHA. Once the num
erical technique has been proven then aspects of localisation and inst
ability can be more thoroughly investigated under a well characterised
loading scenario.