"Virtual Lab": numerically determining charasteristic values for forming simulations

© Photo Fraunhofer IWM

The crystalline structure of metals in forming processes can have a significant influence on mechanical behavior, thus effecting the forming process: for example the development of grain orientation (crystallographic texture) and grain morphology through plastic deformations and thermally-activated phase formation and recrystallization processes in metals. We simulate such changes in the microstructure, as well as the resulting effects on the mechanical material behavior across different scales. In our "Virtual Lab", we predict material properties such as texture development, anisotropy and flow behavior, enabling us to help our clients realize improvements to their process management.

 

On this page:

Predicting microstructure development and microstructure property relationships

Virtual determination of parameters for sheet metal forming simulations

The "Virtual Lab"

Further information  

Predicting microstructure development and microstructure property relationships

A microstructural approach to the assessment and evaluation of forming processes

Multiscale modeling from atomic dimensions to components

Calculation of deformation and recrystallization textures

Virtual determination of characteristic parameters based on microstructure

Description of thermodynamics and kinetics of phase formation processes

Analysis of void evolution (growth, nucleation, closure, void shape)

Development of texture and ansiotropy

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© Photo Fraunhofer IWM

Image 1: Yound's modulus and r-values from AA6014 dependent upon sheet orientation. Comparison of predictions made with the "Virtual Lab" and experimental data.

© Photo Fraunhofer IWM

Image 2: Initial yield surface for the AA6014 aluminum alloy, evaluated at Rp02.

Virtual determination of parameters for sheet metal forming simulations

The "Virtual Lab" is a simulation tool for the numerical determination of macroscopic material properties which takes the microstructure into account. This virtual characterization is an extension of conventional, experimental procedures and can be applied to sheet metal forming in various ways:

Initial yield strength, tensile strength, r-value, Young's modulus considering orientation with respect to rolling direction (image 1)

Determination of arbitrary points on the initial yield surface and parameter identification for use within material models for sheet metal forming (image 2)

Analysis of complex and multi-axial loading conditions, replacing very elaborate experiments

Analysis of loading conditions which cannot be realized experimentally, for example tensile tests of sheets in thickness direction

 

Data produced through our "Virtual Lab" can be used in exactly the same manner as experimental data and is especially applicable to the complex material models which are required when working with modern, high-strength sheet metal materials. These complex material models utilize many parameters which can be identified by the additional data obtained from the "Virtual Lab".

 

The "Virtual Lab"

For the "virtual determination of characteristic values", the model we use considers a material's microstructure in the form of a representative volume element. The microstructure's individual grains are spatially resolved and parameters such as grain shape, grain orientation and phase distribution are taken into account. Only a few experiments are required for the calibration of these micro-models, for example, one single tensile test. After calibration, it becomes quite simple to perform further "virtual testing". By modifying boundary conditions, we can also run compression tests or multi-axial tests and analyze loading conditions which are quite difficult, if not impossible, to realize experimentally.

Through the combination of simple experiments and the data obtained through the Fraunhofer IWM "Virtual Lab", new insights are gained which can be used to formulate more exact descriptions of sheet metal materials. Our know-how and experience enables to put this "virtual characterization" to work in an efficient manner for our clients.
 

Services related to the "Virtual Lab" 

Creation of numerical simulations and models for the "virtual determination of characteristic values"

Experimental analysis of microstructure and texture including the subsequent transfer into the simulation model

Calibration of the "Virtual Lab" based on standard test data

Implementation and evaluation of "Virtual Lab" simulations

 

"Virtual Lab" applications

Simulation of various loading conditions

Characterization of macroscopic values and data for sheet metal materials, for example, flow curve, yield surface and r-values

Provision of "Virtual Lab" data in the same format as the experimental data 

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Further information