Katja Jöchen

Prediction of Texture Evolution in Rolled Sheet Metals by Using Homogenization Schemes

This work deals with comparing the prediction of the development of rolling textures by using a homogenization method that is based on a homogeneous reference material. The proposed homogenization scheme, assuming constant stress polarisations in each phase, has in a natural way the potential to model the transition between Taylor- and Sachs-type textures. Therefore, the stiffness ef the hemogeneous reference material has to be varied between infinitely stiff and infinitely compliant. In the present study, texture evolution during rolling is simulated, showing that the application of different comparison materials in the homogenization scheme leads to the development of different main texture characteristics (Cube, Cu, Bs, Goss) in the orientation distribution function. For efficiently carrying out the rolling simulations using the proposed method, the measured texture information of the bulk aluminum sample is representatively reduced by using a partitioning technique of the orientation space.

Influence of the Crystallographic and the Morphological Texture on the Elastic Properties of Fcc Crystal Aggregates

In this contribution, the prediction of the self-consistent homogenization method with regard to the effective material response of cubic crystal aggregates is analyzed and compared to results from full field simulations. The influence of the crystalline orientation distribution but also the effect of the grain shape on the macroscopic elastic response of sheet metals is especially emphasized.

Qualitative study on texture evolution in rolled sheet metals using homogenization methods

The estimation of the texture in a sheet metal induced by rolling is an important issue for the accurate description of forming operations as, e.g., deep drawing. This work deals with comparing the prediction of the development of rolling textures in aluminum sheets based on different homogenization schemes. The crystallite orientation distribution function (codf) is evaluated by a class of homogenization methods based on a so‐called comparison material and is compared to the widely used Taylor‐type prediction. It is demonstrated that using the model based on the comparison material, the particular choice of the latter strongly influences the intensity distribution of the codf and also the location of the obtained β‐fiber. The proposed homogenization method gives much better results for the reproduction of the codf than the Taylor‐type model. When qualitatively comparing the computational results to experimental data, the location of the maxima in the codf generated by the rolling process are satisfactori...

Micromechanical Modeling of Metal Forming Operations

In this work, a ferritic stainless steel (DC04) is investigated in the following three steps. First, we use micropillar compression test data for the identification of a large strain single crystal plasticity model. In the second step the model is verified based on Electron Backscatter Diffraction (EBSD) measurements in a small specimen subjected to a large strain uniaxial tensile test. The two‐dimensional EBSD data have been discretized by finite elements and subjected to homogeneous displacement boundary conditions for the second step. Finally, we apply a two‐scale Taylor type model at the integration points of the finite elements to simulate the deep drawing process based on initial texture data. The texture data required for the specification of the two‐scale model is determined based on the aforementioned EBSD data and by using a texture component method simultaneously to improve the computation time. The finite element simulations were performed with differently textured sheet metals and compared wi...