Size effects on the constitutive behaviour for brass in sheet metal forming

The reduction of size for mechanical parts is more and more important in metal forming processes. The optimisation of such processes needs more comprehensive use of simulation and FE analysis. The classical modelling used for large and thick sheet specimens is not yet sufficient. An efficient and realistic modelling of the constitutive behaviour is therefore necessary. In this paper, experiments are achieved by tensile and hydraulic bulging tests for brass specimens (CuZn36) to evaluate the size effects on the flow stress. Considering the results, a new modelling of the constitutive behaviour is proposed which takes into account these effects. The material parameters related to this model are identified by an inverse method using the experimental measurements for tensile and bulging tests.