Enhancing accuracy in simulation of sheet metal forming by modelling elasticity of tools

The first ESAFORM Benchmark was dedicated to the cylindrical cup drawing test and involved the participation of 11 laboratories worldwide. Despite the wide variety of computational models adopted, several experimental results were not accurately predicted, and no conclusive explanation for the observed discrepancies was identified, motivating further investigation. Using the same benchmark configuration, the present study examines the influence of modelling tools as rigid or elastic on the accuracy of sheet metal forming simulations. The effect of the elasticity of tools is quantified and related to discrepancies previously reported in the benchmark. Different process conditions, including variations in blank thickness and diameter were analysed for two materials: AA6016 aluminium alloy and DC06 steel. The results demonstrate that considering the elasticity of tools significantly improves the prediction of punch force evolution, cup wall thickness, and earing profile, particularly in processes involving ironing. Elastic deflection of the tools modifies the contact pressure distribution under the blank-holder and increases the effective punch–die gap, leading to more accurate predictions of ironing forces and wall thickness. These findings help explain discrepancies observed in the first ESAFORM Benchmark and highlight that incorporating the elasticity of tools is essential for high-fidelity sheet metal forming simulations, particularly when ironing occurs.