Introducing high strength and ductility twinning induced plasticity (TWIP) steels for European automotive applications through advanced material modeling (TWIP4EU) : final report

The aim of TWIP4EU is to promote the introduction of modern twinning induced plasticity (TWIP) steels as candidate material for production of lightweight automobile components. To introduce a new steel grade like high strength and ductility TWIP-steel for large scale applications in industrial practice, a thorough validation of the material behaviour with useable material laws implementable in commercial finite element codes must be available since numerical simulations are used all along the production process of car body parts. For this purpose, this project proposes a novel and advanced approach towards modelling the deformation and forming behaviour of new TWIP-steels. The project comprises a comprehensive experimental plan combined with the development of a constitutive framework motivated from micromechanical quantities to describe the deformation behaviour of TWIP-steels. Based on the results from microstructure analyses, macroscopic test and forming experiments the material was extensively characterized. The experimental results were taken into consideration for the development of the constitutive framework. The developed TWIP4EU material model was implemented into two commercially available finite element software packages. Prototype components were successfully produced out of TWIP-steel material. The superior formability of TWIP-steel could be demonstrated. The numerical results which are obtained from simulation using the developed material model are in good agreement with the experimental findings.