Abstract
The springback phenomenon is defined as the elastic recovery of the residual stresses produced during the forming of a material. An accurate prediction of springback puts high demands on the constitutive modeling. A constitutive model for springback prediction should of course be able to accurately predict the stress state after the forming phase. However, it should also be able to predict the material behavior during the unloading phase. In classical plasticity theory, the unloading of a material after plastic deformation is assumed to be linearly elastic with the stiffness constantly equal to Young’s modulus. However, several experimental investigations have revealed that this is an incorrect assumption.
The main purpose of the present work has been to formulate a constitutive model that can accurately predict the unloading behavior of a sheet metal material. The new model is based on a classical elasticplastic framework, and is totally independent on the choice of yield criterion and hardening evolution law.
References
Lems W. The change of Young modulus after deformation at low temperature and its recovery. Dissertation, Delft 1963.
Morestin F., Boivin M. On the necessity of taking into account the variation in the Young modulus with plastic strain in elastic plastic software. Nuclear Engineering Design 162:107–116, 1996.
Yoshida F., Uemori T., Fujiwara K. Elastic-Plastic behavior of steel sheets under in-plane cyclic tension-compression at large strain. International Journal of Plasticity, 18:633–659, 2002.
Cleveland R.M., Ghosh AK. Inelastic effects on springback in metals. International Journal of Plasticity 18:769–785,2002.
Troiano E., Parker AP, Underwood J, Mossey C. Experimental data, numerical fit and fatigue life calculations relating to the Bauschinger effect in high strength steels. Journal of Pressure Vessel Technology 125:330–334,2003.
Eggertsen P.A. Prediction of springback in sheet metal forming, with emphasis on material modeling. Licentiate thesis, Chalmers University of Technology, 2009.
Eggertsen P.A., Mattiasson K. Material modeling for accurate springback prediction. In 12 th international ESAFORM Conference on Material Forming, 2009.
Yoshida F., Uemori T. A model of large-strain cyclic plasticity and its application to springback simulation. International Journal of Mechanical Sciences 45:1687–1702, 2003.
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Eggertsen, PA., Mattiasson, K. On the Modeling of the Unloading Modulus for Metal Sheets. Int J Mater Form 3 (Suppl 1), 127–130 (2010). https://doi.org/10.1007/s12289-010-0723-2
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DOI: https://doi.org/10.1007/s12289-010-0723-2