Analysis of yield locus description on springback behaviour of CR700Y980T-DP steel

M Grubenmann,H Rösen,P Hora,J Heingärtner,A Torkabadi,N Manopulo,T Van Den Boogaard,K Barth

doi:10.1088/1757-899x/418/1/012108

M Grubenmann, H Rösen + Show 6 more

Open Access

https://doi.org/10.1088/1757-899x/418/1/012108

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Abstract

To precisely predict springback, the stress and strain state has to be described correctly during the forming process and after load removal. In this work, different yield locus descriptions are considered for springback prediction of a CR700Y980T-DP steel with a thickness of 1.5 mm. Experiments and Finite Element Analyses (FEA) with LS-DYNA of a U-bending validation tool were performed and springback predictions compared. In the FEA Hill48, Barlat89 and Barlat’s YLD2000 for isotropic hardening, Yoshida-Uemori as a kinematic hardening model and the homogeneous anisotropic hardening (HAH) model are chosen. Monotonic and two-step tensile tests with a directional change of stress are performed and cyclic tension-compression tests are used to determine the material parameters of the investigated hardening models. It is seen that both Yoshida-Uemori and HAH models provide a significant improvement in the springback prediction. The results, however greatly depend on the identification procedure as well as on the modelling of cross-loading contraction effects.

Highlights

The focus on reduction of CO2 emissions in the automotive industry has led to an increased usage of new steel alloys with high strength such as various advanced high strength steels
This study focuses on the influence of the yield criterion as it has been emphasized as an important factor for the amount of springback [5]
In this study a CR700Y980T-DP steel with a thickness of 1.5 mm was tested with monotonic and twostage tensile tests, Bulge tests and cyclic tension-compression tests to determine the isotropic material models according Hill48, Barlat89 and YLD2000 and the anisotropic material models Yoshida-Uemori and homogeneous anisotropic hardening (HAH). As it can be expected both anisotropic hardening models enabled a significant improvement in the springback prediction

Summary

Conference Paper

Analysis of yield locus description on springback behaviour of CR700Y980T-DP steel. Author(s): Grubenmann, Michael; Barth, Konrad; Heingärtner, Jörg; Manopulo, Niko; Hora, Pavel; Torkabadi, Aydin; Van Den Boogaard, Ton; Rösen, H.

IOP Publishing

Introduction

Model parameter

Evolution of h

Conclusions