Numerical modeling and digital image correlation strain measurements of coated metal sheets submitted to large bending deformation

in Proceedings of the 16th ESAFORM conference on Material Forming (2013)

The recently developed SSH3D solid-shell element, which is based on the Enhanced Assumed Strain (EAS) and the Assumed Natural Strain (ANS) techniques, is utilized for the modeling of a severe bending ... [more ▼]

The recently developed SSH3D solid-shell element, which is based on the Enhanced Assumed Strain (EAS) and the Assumed Natural Strain (ANS) techniques, is utilized for the modeling of a severe bending sheet forming process. To improve the element's ability to capture the through thickness gradients, a specific integration scheme was developed. In this paper, the performances of this element for the modeling of the T-bent process were assessed thanks to comparison between experimental and numerical results in terms of the strain field at the outer surface of the sheet. The experimental results were obtained by Digital Image Correlation. It is shown that a qualitative agreement between experimental and numerical results is obtained but some numerical parameters should be optimized to improve the accuracy of the simulation predictions. In this respect, the influence of the penalty coefficient of the contact modeling was analyzed. [less ▲]

Compression test for plastic anisotropy characterization using optical full-field dis-placement measurement technique

in Steel Research International (2012)

In this work, a constitutive law, its identification and its validation for TA6V titanium alloy are presented. The material characteri-zation is achieved by quasi-static monotonic tensile and compression ... [more ▼]

In this work, a constitutive law, its identification and its validation for TA6V titanium alloy are presented. The material characteri-zation is achieved by quasi-static monotonic tensile and compression tests at several strain rates and in three orthogonal material orientations. Constitutive model as Johnson-Cook which describes the strain rate sensitivity of the plastic material response is used in order to identify the initial yield locus at a common strain rate (10-3 s-1). The macroscopic orthotropic yield criterion chosen is the well-known CPB06 proposed by Cazacu et al., which describes both the tension/compression asymmetry and the anisotropic behavior of hcp metals and alloys. Voce type isotropic hardening model is used for simplicity reasons. A compression test on ellipsoidal cross-section specimen is selected for validation purpose, where 3 Digital Image Correlation 3D systems are used in order to acquire the evolution of the full field displacement/strain during the test. Coulomb friction coefficient between the dies and the specimen is computed by means of inverse modelling. A good agreement on the prediction of the load as a function of axial displacement of the specimen is found. [less ▲]

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

in AIP Conference Proceedings (2011), 1383

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 ... [more ▼]

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. [less ▲]