Spring-back simulation based on characterization of sheet metals under reverse plastic strains

Publisher Summary This chapter presents spring-back simulation based on characterization of sheet metals under reverse plastic strains. The application of new sheet materials is often impeded by the insufficient predictability of the spring-back complicated by the Bauschinger effect. The prediction of spring-back during sheet forming requires the exact calculation of the stress distribution in the sheet after one or more cycles of reverse plastic deformations. A Chaboche-type combined hardening model has been used to enable such calculations. The required material parameters have been determined from cyclic stress-strain curves measured in tension- compression tests. To facilitate those tests also with thin-sheet specimens, a special test rig and a new specimen design have been developed. A chaboche-type combined hardening model has been invoked through the user subroutines in a commercial finite element (FE) code. A number of studies from simple-hat profiles to rather complex real automotive parts in cooperation with different industrial partners have been performed. Other than different steel sheets, sheet magnesium alloy MgAZ31 has been investigated.