Issue 53

R. Harbaoui et alii, Frattura ed Integrità Strutturale, 53 (2020) 295-305; DOI: 10.3221/IGF-ESIS.53.23 304 This allows to represent the load surface f(  ,2  ) in space 1 2 3 ( , , ) x x x . Using the base of constraint deviators: 2 2 D x X  σ 3 3 D x X  σ For the load surface, it is clear that the material is more resistant in simple shear than in uniaxial traction. C ONCLUSION n this work, based on an experimental database, we have developed an identification strategy centered on the parameters of plasticity, the hardening law and lankford coefficients in order to raise previously unresolved identification issues. After construction of the model, an identification methodology was presented from the monotonic tensile and compression hardening curves. The first step consists in identifying the tensile and compression curves by the different hardening laws in order to choose the most adequate law to best describes the material behavior, while comparing it with the experimental curves. The second step of the strategy consists in identifying the anisotropy parameters of the material studied by the CPB06 criterion using the Ludwick law as a hardening law. The used criterion takes into account the strong anisotropy as well as the SD effect "strength differential" translated by the traction-compression asymmetry. A validation by comparing the model to the experimental database was carried out; the validation of the model is established using the experimental values of the lankford coefficient. A comparison between the CPB06 and Barlat criterions were carried out. It is found that the anisotropy evolves in the same way for an identification strategy using the CPB06 criterion as well as the Barlat criterion. On the other hand, the validation by the Lankford coefficient is well respected by the CPB06 criterion. Thus, from the identification results of the anisotropy parameters and the Lankford coefficients, it was possible to verify that the identification using the CPB06 criterion gives clearly more efficient results compared to other criteria, in particular Barlat91. R EFERENCES [1] Yueqian, J. (2011). Study on anisotropic plasticity and fracture of lightweight metal sheets, M.S. University of Central Florida, 2013 B.S. Northwestern Polytechnical University, China [2] Manuel, M., Hector, L.G. , Verma, R., Tong, W. (2006). Microstructural effects of AZ31 magnesium alloy on its tensile deformation and failure behaviors, Materials Science and Engineering, A418, pp. 341–356. [3] Roberts C. Sheldon (1960). Magnesium and Its Alloys, New York, NY: John Wiley and Sons [4] Yuqian, W., Duke, C., Yanyao, J. (2019). An experimental study of anisotropic fatigue behavior of rolled AZ31B magnesium alloy, DOI: 10.1016/j.matdes.2019.108266. [5] Graff, S., Brocks, W., Steglich, D. (2007). Yielding of magnesium: from single crystal to polycrystalline aggregates , Int. J. Plast., 23 (12), pp. 1957-1978 [6] Kelly, E.W., Hosford, W.F.(1968). Plane-strain compression of magnesium and magnesium alloy crystals. Trans.Metall. Soc. AIME 242, 5–13. [7] Yueqian, J, Yuanli B. (2016). Experimental study on the mechanical properties of AZ31B-H24 magnesium alloy sheets under various loading conditions, International Journal of Fracture, 197, pp. 25–48. [8] Lou, X.Y. , M. Li, Boger , R.K. , Agnew, S.R. , Wagoner, R.H. (2007). Hardening evolution of AZ31B Mg sheet Int. J. Plast., 23 (1), pp. 44-86. [9] Znaidi, A., Daghfas, O., Guellouz, S., Nasri, R. (2016). Theorical study on mechanical properties of AZ31B Magnesium alloy Sheets under multiaxial loading, Frattura ed Integrità Strutturale, 38, 135-140; DOI: 10.3221/IGF-ESIS.38.18 [10] Znaidi, A., Daghfas, O., Gahbiche, A., et al. (2016). Identification strategy of anisotropic behavior laws: application to thin sheets of A5. J. Theor. Appl. Mech, 54, pp. 1147–1156. DOI:10.15632/jtam-pl.54.4.1147. I