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International Journal for Multiscale Computational Engineering
Impact-faktor: 1.016 5-jähriger Impact-Faktor: 1.194 SJR: 0.554 SNIP: 0.68 CiteScore™: 1.18

ISSN Druckformat: 1543-1649
ISSN Online: 1940-4352

International Journal for Multiscale Computational Engineering

DOI: 10.1615/IntJMultCompEng.2015014764
pages 25-43

A MULTISCALE APPROACH FOR THERMO-MECHANICAL SIMULATIONS OF LOADING COURSES IN CAST IRON BRAKE DISCS

Stefan Schmid
Institute of Materials and Processes, Karlsruhe University of Applied Science, Moltkestrasse 30, D-76133 Karlsruhe, Germany
Daniel Schneider
IAM-CMS, Karlsruhe Institute of Technology, Kaiserstrasse 12, D-76131 Karlsruhe, Germany
Christoph Herrmann
Institute of Materials and Processes, Karlsruhe University of Applied Science, Moltkestrasse 30, D-76133 Karlsruhe, Germany
Michael Selzer
Institute of Materials and Processes, Karlsruhe University of Applied Science, Moltkestrasse 30, D-76133 Karlsruhe, Germany; IAM-CMS, Karlsruhe Institute of Technology, Kaiserstrasse 12, D-76131 Karlsruhe, Germany
Britta Nestler
Institute of Materials and Processes, Karlsruhe University of Applied Science, Moltkestrasse 30, D-76133 Karlsruhe, Germany; IAM-CMS, Karlsruhe Institute of Technology, Kaiserstrasse 12, D-76131 Karlsruhe, Germany

ABSTRAKT

This article presents a multiscale approach for the simulation of coupled heat and stress evolution induced by different loading courses in gray cast iron brake discs. The concept integrates the microstructural properties as homogenized material laws into the macroscopic computations. Extensive experimental testing is required to establish a complete set of material parameters needed to conduct thermo-mechanical simulations on a macroscopic length scale. In addition, the microstructure can vary within the disc due to differences in wall thicknesses and cooling rates. In order to reduce the experimental effort and to estimate the influence of microstructure characteristics on macroscopic heat and stress distributions, simulations on the mesoscopic scale resolving the heterogeneous microstructure with graphite flakes in a pearlite matrix are conducted. The workflow to derive the elasto-plastic properties according to its microstructure is demonstrated for a typical cast iron material. Geometrical parameters of the graphite phase distributions and shape factors composed from micrographic analysis are used to generate representative volume elements (RVE) and to define the metallographic constituents. The information serves as input parameters to algorithmically construct a 3D cast iron microstructure. The elastic and elasto-plastic material models of the constituents are briefly elucidated. In order to simulate the different material behavior in tension and compression, a crack opening and crack closure mechanism is included. The potential of complementing and substituting experimental testing is shown by a quantitative comparison of the simulation results with experimental data at ambient temperature. Both virtual tension and compression tests are executed as well as a tension-compression cycle and the determination of the yield surface of the material. The presented approach provides a first step into a versatile range of applications and illustrates a broad potential for future challenges of multiscale modeling in the field of thermo-mechanical failure analysis.