Length changes and texture prediction during free end torsion test of copper bars with FEM and remeshing techniques

Abstract

FEM numerical simulations of the experimental free end torsion tests [Toth, L.S., Jonas, J.J., Daniel, D., Bailey, J.A., 1992. Texture development and length changes in copper bars subjected to free end torsion. Textures Microstruct. 19,[245][246][247][248][249][250][251][252][253][254][255][256][257][258][259][260][261][262] of copper cylindrical bars were analysed in the present study. The self-made Finite Element (FE) code LAGAMINE was used to compute numerical prediction of the Swift effect, i.e. the lengthening of the cylinder during the torsion. The material behaviour was represented by an interpolation law [Habraken, A.M., Duchêne, L., 2004. Anisotropic elasto-plastic finite element analysis using a stress-strain interpolation method based on a polycrystalline model. Int. J. Plasticity 20 (8-9), 1525-1560] linked with a Taylor poly-crystal plasticity model either based on a strain rate insensitive or a visco-plastic crystal plasticity model. The influence of texture evolution was analysed. A torsion dedicated remeshing technique was developed to allow very large strain simulations. Predicted axial lengthening and predicted textures were compared to experimental measurements. A good agreement was obtained for shear strain up to 2.0. The Swift effect related angular shift of the pole figure maxima from symmetrical orientations was reproduced correctly.

Forming forces in single point incremental forming: prediction by finite element simulations, validation and sensitivity

“…It applies methods proposed by Wang and Wagoner [28] to prevent shear locking and volumetric locking, associated with a corotational reference system. Its description can be found in Duchêne's article published in 2007 [29]; -the contact element CFI3D [30] is coupled with the BWD3D solid element. It checks the contact at the surface integration points of the metal sheet with the spherical tool, which is assumed to be rigid (i.e., non-deformable).…”

Multisite model prediction of texture induced anisotropy in brass

“…This is related to the simplified geometry of the tube considered here and to the significant tube diameter reduction illustrated on the secondary axis in Figure 3, as will be shown in section 4. . This rotation of texture was mentioned in [5,11] to be related to an increase of texture components responsible for the axial effects (Swift effect). The intensity of the texture components are better reproduced with models taking twinning into account.…”

Insight into a model for large strain anisotropic elasto-plasticity

“…However, the evolution of the material symmetries with nonproportional plastic strains is intuitive and has been observed experimentally, see for example References [28][29][30][31][32]. This evolution is closely related to the texture evolution of the microstructure, also observed experimentally, see for example References [33][34][35][36][37][38][39][40][41][42][43]. Texture evolution involves both changes in the yield function and in the preferred directions.…”

“…From Eqs. (28), (36) and (37), we have (40) This indicates that the ratio of ρ to η m may play a more important role in the evolution of the anisotropic axes than the specific values of ρ, η and m. If we set the ratio to be a constant C, we have…”