Stabbing of metal sheets by a triangular knife. An archaeological investigation

In order to provide a basis for comparative evaluation of ancient and early modern metal armour, experiments have been made with a simplified knife to investigate the action of stabbing into thin metal sheets. The forces required for indentation, perforation and extension of the slit were measured for sheets simply supported over a circular hole. A range of metals in different thermomechanical states, with Vickers hardnesses from 5 to 200 VPN and fracture toughnesses (crack-tip opening displacements) from 0.4 to 1.5 mm, and thicknesses from 0.5 to 2 mm, was employed. The behaviour of the simplified knife could be modelled approximately using the analysis by Wierzbicki and co-workers (Int. J. Mech. Sci. 35 (1993) 209; Int. J. Impact Eng. 19 (1997) 667) for loading a thin plate edge-on by a wedge. The results demonstrate that it is possible to rank the protective value of early armour in different metals, using readily determined mechanical properties.