6. Conclusion

From a more general point of view, future work should make it possible to significantly improve the previous formulation of friction and the results of the various current approaches:

• numerical simulation, which is the only way to specify unambiguously the consequences on the part of a change in friction conditions, to better quantify the uncertainties of current methods for stripping simple forming tests (snap ring, Erichsen, Swift) and to ensure the stripping and interpretation of stamping tests on industrial parts;

• test methods, to improve their reproducibility and relevance, in particular by comparing the results of tribometer tests and stamping tests;

• observation of sheet metal before and after rubbing or forming, to highlight microscopic friction mechanisms and formulate simple friction...