On the definition of an kinematic hardening effect graph for sheet metal forming process simulations

• KHEG is presented as the indicator of the hardening behaviour effect.
• Simple tensile test characterisation is only needed to create the graph.
• The graph is validated my means of three point bending test procedures.
• The graph allows to decide if further complex material characterisation is needed.
• The graph is able to identify critical non-reversal strain path influences.

The objective of this work is to develop a kinematic hardening effect graph (KHEG) which can be used to evaluate the effect of kinematic hardening on the model accuracy of numerical sheet metal forming simulations and this without the need of complex material characterisation. The virtual manufacturing process design and optimisation depends on the accuracy of the constitutive models used to represent material behaviour. Under reverse strain paths the Bauschinger effect phenomenon is modelled using kinematic hardening models. However, due to the complexity of the experimental testing required to characterise this phenomenon in this work the KHEG is presented as an indicator to evaluate the potential benefit of carrying out these tests. The tool is validated with the classic three point bending process and the U-channel width drawbead process. In the same way, the capability of the KHEG to identify effects in forming processes that do not include forming strain reversals is identified.