Gaëtan Gilles

Experimental characterization and constitutive modeling of TA6V mechanical behavior in plane strain state at room temperature

This paper presents an experimental and theoretical study of the quasi‐static behavior of TA6V titanium alloy in plane strain state. In order to quantify the anisotropy of the material, tests were carried out at room temperature on specimens cut out from a sheet along three loading directions. The initial yield locus is described by the phenomenological CPB06ex3 criterion and Voce’s type isotropic hardening is used. Finite element simulations are performed and compared with the experiments.

Material parameter identification of Cazacu's model for Ti6Al4V using the simulated annealing algorithm

Phenomenological yield criteria are generally described by many material parameters. A technique to identify these parameters is required to find the best fit to the results of the mechanical tests. The parameter identification by the classical simulated annealing technique is presented in this paper. This algorithm, based on works by Metropolis et al, is a global optimization method that distinguishes between different local optima to reach the global optimum. The anisotropic model used in this study is the one proposed by Cazacu et al. To prove the efficiency of the proposed algorithm, the material parameters of Ti6Al4V titanium alloy are identified and compared with those obtained using different identification procedures and the same experimental data.

Modeling the ductile fracture and the plastic anisotropy of DC01 steel at room temperature and low strain rates

This paper presents different extensions of the classical GTN damage model implemented in a finite element code. The goal of this study is to assess these extensions for the numerical prediction of failure of a DC01 steel sheet during a single point incremental forming process, after a proper identification of the material parameters. It is shown that the prediction of failure appears too early compared to experimental results. Though, the use of the Thomason criterion permitted to delay the onset of coalescence and consequently the final failure.

Experimental and numerical study of TA6V mechanical behavior under different quasi-static strain paths at room temperature

This paper presents an experimental study of the quasi-static mechanical behavior of TA6V titanium alloy. Different monotonic tests were carried out in several orientations in the plane of the sheet in order to characterize the anisotropy and the tension-compression asymmetry exhibited by the material. Initial yielding is modeled by the phenomenological CPB06 criterion and Voces isotropic hardening is used to describe its evolution. The simulation of a deep-drawing process is performed using the proposed constitutive modeling and compared with experimental data.

Experimental Investigation and Phenomenological Modeling of the Quasi-Static Mechanical Behavior of TA6V Titanium Alloy

This paper proposes an experimental and numerical investigation of the quasi-static mechanical behavior of TA6V at room temperature. Different loading conditions (tension, compression, plane strain and simple shear) were applied on a 0.6 mm thick sheet in several in-plane directions. Based on the experimental results, several identifications are performed to determine the parameters involved in the CPB06 yield criterion and its extensions. The error/time computation ratio for the different identifications is next analyzed to fix the choice of the yield criterion. The latter is finally associated with an isotropic hardening law on the one side and a formulation taking into account the evolution of the yield locus on the other side in order to describe the material. The ability of the proposed formulations to predict the TA6V response is studied in the case of a deep-drawing process.