Application of the GTN Model in Ductile Fracture Prediction of 7075-T651 Aluminum Alloy

Document Type: Research Paper

Authors

Department of Mechanical Engineering, Ferdowsi University of Mashhad

Abstract

In this paper the capability of Gurson-Tvergaard-Needleman (GTN) model in the prediction of ductile damage in 7075-T651 aluminum alloy is investigated. For this purpose, three types of specimens were tested: Standard tensile bars, Round notched bar (RNB) specimens and compact tension (C(T)) specimens. Standard tensile bar tests were used to obtain the mechanical properties of the material and to calibrate the independent parameters of GTN model. RNB and C(T) specimen test results were used for validation of the calibrated parameters. Finite element analyses were carried out using ABAQUS commercial software for two purposes; calibration of the GTN model parameters and validation of the model predictions. The comparison between the finite element analyses and the test results suggested that the GTN model is capable of damage prediction in notched specimens, but not a good in cracked specimens. Finally, To show the applicability of the model in industry-level problems, the model is used for damage predictions of internal pressure vessels made of 7075-t651 aluminum alloy.

Keywords


[1] Jordon J. B., 2009, Damage characterization and modeling of a 7075-T651 aluminum plate, Materials Science and Engineering 527: 169-178.
[2] Fabregue D., Pardoen T., 2008, A constitutive model for elastoplastic solids and secondary voids, Journal of the Mechanics and Physics of Solids 56: 719-741.
[3] Tvergaard V., Needlemann A., 1984, Analysis of the cup-cone fracture in a round tensile bar, Acta Metallurgica 32: 57-69.
[4] Chang-Kyun O., 2007, A phenomenological model of ductile fracture for API X65 steel, Internatinal Journal of Mechanical Science 49: 1399-1412.
[5] Acharyya S., Dhar S., 1999, A complete GTN model for prediction of ductile failure of pipe, Journal of Materials Science 43: 1897-1909.
[6] Chiluverin S., 2007, Computational Modeling of Crack Initiation in Cross-roll Piercing, MSc Thesis, Massachusetts Institute of Technology.
[7] Benseddiq N., Imad A., 2008, A ductile fracture analysis using a local damage model, International Journal of Pressure Vessels and Piping 85: 219-227.
[8] Bernauer G., Brocks W., Schmitt W., 1999, Modifications of the beremin model for cleavage fracture in the transition region of a ferritic steel, Engineering Fracture Mechanics 64: 305-325.
[9] Nielsen K. L., 2008, Ductile damage development in friction stir welded aluminum (AA2024) joints, Engineering Fracture Mechanics 75: 2795-2811.
[10] Abendorth M., Kuna M., 2006, Identification of ductile damage and fracture parameters from the small punch test using neural networks, Engineering Fracture Mechanics 73: 710-725.
[11] Maout N. L., Thuillier S., Manach P. Y., 2009, Aluminum alloy damage evolution for different strain paths – application to hemming process, Engineering Fracture Mechanics 76: 1202-1214.
[12] He M., Li F., Wang Z., 2011, Forming limit stress diagram prediction of aluminum alloy 5052 based on GTN model parameters determined by in situ tensile test, Chinese Journal of Aeronautics 24: 378-386.
[13] Li X., Song N., Guo G., 2012, Experimental measurement and theoretical prediction of forming limit curve for aluminum alloy 2B06, Transactions of Nonferrous Metals Society of China 22: 335-342.
[14] Teng B., Wang W., Liu Y., Yuan S., 2014, Bursting prediction of hydroforming aluminum alloy tube based on Gurson-Tvergaard-Needleman damage model, Procedia Engineering 81: 2211- 2216.
[15] Gurson A. L., 1977, Continuum theory of ductile rupture by void nucleation and growth: part I – yield criteria and flow rules for porous ductile media, Journal of Engineering Materials and Technology 99(1): 2-15.
[16] Tvergaard V., 1982, On localization in ductile materials containing spherical voids, International Journal of Fracture 18: 37-52.
[17] Annual Book of ASTM Standard, 1997, Standard test methods for tension testing of wrought and cast aluminum- and magnesium-alloy products, ASTM B557-10.
[18] Annual Book of ASTM Standard, 1997, Standard test method for plane strain fracture toughness of metallic materials , ASTM E-399-90.
[19] Tajally M., Huda Z., Masjuki H. H., 2010, A comparative analysis of tensile and impact-toughness behavior of cold-worked and annealed 7075 aluminum alloy, International Journal of Impact Engineering 37: 425-432.