Inverse parameter identification of sheet metals utilizing the distribution of field variables

The accurate simulation of sheet metal forming processes requires the accurate description of material behaviour. This is accomplished by utilization of sophisticated constitutive models that use several parameters. This work proposes a procedure which makes use of the distribution of field variables to identify the material parameters by the help of inverse analysis. In this procedure, the distribution of the field variables on a sheet surface is captured by an optical measurement system during a process, which is capable of computing the displacement and strain distribution. The finite element simulation of the same process is also performed. However, it is not possible to compare the experimental data directly with the simulation results because of the differences regarding the coordinate systems and discretizations in space and time domain. These problems are solved by coordinate transformations and parameter mapping. The procedure is applied to simple tension test as an application example, in which the flow curves of two materials are calculated successfully.