Design of an indicator to characterize and classify mechanical tests for sheet metals

• A criteria to rate and rank material mechanical tests is presented.
• A strategy for choosing the heterogeneous test to identify model parameters.
• The use of histograms in the analysis of the evolution of strain states.
• Comparison and analysis of both classical and recent mechanical tests.
• Validation of the indicator methodology using other methodology.

The aim of this paper is the design of a quantitative indicator able to distinguish, rate and rank different mechanical tests used to characterize the material behavior of sheet metals. This indicator is formulated considering (i) the strain state range, (ii) the deformation heterogeneity and (iii) the strain level achieved in the test, based on a continuous evaluation of the strain field up to rupture. In order to demonstrate the relevance of the proposed indicator, numerical simulations of classical as well as recent heterogeneous tests were carried out using as input the virtual mechanical behavior of DC04 mild steel. A complex elastoplastic phenomenological model including macroscopic rupture criterion was used. The performance of these tests was compared and their reliability on the mechanical behavior characterization was rated. By using the indicator, a ranking scale ordering the different tests is presented. The obtained results are validated by means of a material parameter sensitivity study. Finally, the proposed indicator can be applied to design new heterogeneous experiments that improve the mechanical characterization of sheet metals and, consequently, material parameter identification.