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+Exposé for the PhD Thesis of Dipl.-Ing. Daniel Mevec
+
+%===================================================================
+1) Objective
+%===================================================================
+
+
+The goal of this thesis is to develop a Finite Element Method (FEM) simulation chain that will model induction heat treatment of different steel work pieces.
+This model will endeavor to predict the final hardness and residual stress distributions of the hardened bearing journals, enabling precise process design for optimal hardness distribution.
+
+The simulation itself will cover the entire heat treatment process – i.e. austenitizing, quenching, and annealing – and will include modeling of the phase transformations and transformation induced plasticity (TRIP).
+
+
+%===================================================================
+2) State of the Art
+%===================================================================
+
+
+Induction hardening is used throughout many industries for diverse purposes, which can generally be summed into two categories: through hardening of semi-finished products and surface hardening of complex shaped components [Rudnev2014].
+Due to its variable heating rates and depths as well as it being easily automated and virtually emission free, induction heating technology is continually gaining importance.
+
+Conventional heat treatment facilities can however not be easily exchanged for their electro-magnetic counterparts, as the differing processing windows require extensive know-how to achieve comparable results in microstructure and material properties [Sackl2016,Vieweg2017c,Vieweg2017a].
+
+Process parameters are system dependent and can only be transferred from one induction facility to another with significant knowledge of the material in question, the induction facilities, and the physics of induction heating itself.
+These difficulties also apply to transfer of parameters between different product geometries.
+A consistent computational simulation framework consisting of a multi-physical model chain is therefore required to understand and predict the whole heat treatment process.
+
+Optimizing for calculation speed and resource usage reduces most simulations of electro-magnetic interactions to planar or axisymmetric models.
+For parts of more complex geometry than a cylinder, mirror and rotational symmetries are exploited to reduce the geometry to 1/4, 1/8, and in the case of gears 1/144 [Barglik2014].
+
+Automotive crankshafts are hardened inductively by rotating while shaped conductive coils rest on the tops of their bearing surfaces.
+After quenching, they are moved to a conventional oven for tempering.
+This heat treatment is essential to reach the lifetimes demanded of these highly wear subjected parts.
+This process is not conducive to simplification through symmetries, therefore the entire geometry must be simulated and other simplification schemes need to be used.
+
+Other publications assume the magnetic permeability to be linear, which allows harmonic simulation of the electro-magnetic interactions [Barglik2014, Bui2015, Gleim2015].
+While the magnetic hysteresis curve can be linearized [Labridis1989], this linearization assumes no change of the B-H curve of the metal and is dependent on the strength of the magnetic field permeating the material, both of which are not constant (neither over time nor space) in a surface heated  work piece.
+
+
+
+%===================================================================
+3) Methodological Approach
+%===================================================================
+
+
+The dissertation is taking place within COMET project A3.
+34 “Computer aided process optimization and residual stress and property design of induction hardened products” is using its project structure, although only work packages 3, 5, and 6 are explicitly tied to the thesis and will be expanded upon in this exposé.
+
+%-------------------------------------------------------------------
+3.1)	Work Package 3 – Framework for multiphysics modelling of the complete induction heat treatment (MCL)
+%-------------------------------------------------------------------
+
+This work package is concerned with modelling the in house induction test rig of the Materials Center Leoben.
+The objects of this step are simple rods of 50CrMo4 steel.
+
+A python framework controls the manual coupling [Hameyer1999] of the physics simulations in Abaqus.
+The simulation is split into electromagnetic (EM), heat transfer (HT) and stress analysis (SA) models; ET and HT iterate through the heating process and are stitched together by the framework to function as input for the SA module.
+Subroutines within the Abaqus calculation incrementally compute phase transformations and associated changes in volume.
+
+The test rig is instrumented and allows for validation of temperatures of the surface and center of the rods.
+While process parameters serve as power input and verification for the temperature progression, heat treated samples will be analyzed for phase distribution, hardness and residual stresses to verify the subroutines.
+
+%-------------------------------------------------------------------
+3.2)	Work Package 5 – Modelling of surface hardening facility and process
+%-------------------------------------------------------------------
+
+The knowledge and techniques gleaned in work package 3 will be transferred to a 3D model of a crankshaft, while different simplifications of the model will be tried for optimal computation time.
+A modular approach in the programming of the python framework will allow for implementing different simulation schemes without much reprogramming.
+The material parameters also need to be updated to represent the crankshaft steel (C38) and behave accordingly.
+
+The complex geometry and makeup of the induction coil used must be implemented in such a way to allow for rotation between coil and shaft during the heating process.
+
+Finally, a grinding of the bearing journal surfaces, which causes severe stress redistribution after annealing, will be added.
+This last process step includes material removal and will likely constitute a further module added to the framework.
+
+%-------------------------------------------------------------------
+3.3)	Work Package 6 – Simulation and Validation of heat treatment of crankshafts
+%-------------------------------------------------------------------
+
+The final work package deals with analyzing the distribution of local properties in the Journals of the crankshaft.
+Micrographs, Vickers hardness tests and residual stress measurements via XRD and synchrotron will be performed on sample crankshafts from different steps in the process chain.
+
+Additionally, the physical induction oven at the BMW plant will be instrumented as thoroughly as the machine allows and real time process parameters will be recorded to aid the generation of input signals for simulation.
+
+Once all possible distribution data has been accumulated for different steps during the process, final simulations will verify the simulation and allow it to be integrated into BMW’s motor life cycle assessment where the residual stresses will serve as a base for fatigue calculations.
+
+
+%===================================================================
+4) Expected Results
+%===================================================================
+
+
+This thesis is expected to yield an induction process chain simulation as complete as has never been implemented in literature, while simultaneously dealing with hugely complex 3D geometries and nonlinear material behavior.
+
+It also aims to further understanding of heat distribution and the impact of induction heating on stresses in complex geometries.
+
+
+
+%===================================================================
+5) Literature
+%===================================================================
+
+
+[Barglik2017] Barglik, J. , Smalcerz, A. , Influence of the magnetic permeability on modeling of induction surface hardening, COMPEL (2017) 36, 555-564
+[Bui2015] Bui, H. -T. , Hwang, S. -J. , Modeling a working coil coupled with magnetic flux concentrators for barrel induction heating in an injection molding machine, International Journal of Heat and Mass Transfer (2015) 86, 16-30
+[Gleim2015] Gleim, T. ; Schröder, B. , Kuhl, D. , Nonlinear thermo-electromagnetic analysis of inductive heating processes, Archive of Applied Mechanics (2015) 85, 1055-1073
+[Hameyer1999] Hameyer, K. , Driesen, J. , De Gersem, H. , Belmans, R. , The Classification of Coupled Field Problems, IEEE Transactions on Magnetics (1999) 35, 1618-1621
+[Labridis1989] Labridis, D. , Dokopoulos, P. , Calculation of Eddy Current Losses in Nonlinear Ferromagnetic Materials, IEEE Transactions on Magnetics (1989) 25, 2665-2669
+[Rudnev2014] Rudnev, V. , Totten, G. (Eds. ), ASM Handbook Volume 4C: Induction Heating and Heat Treatment, A S M International (2014)
+[Sackl2016] Sackl, S. , Zuber, M. , Clemens, H. , Primig, S. , Induction tempering vs conventional tempering of a heat-treatable steel, Metallurgical and materials transactions a (2016) 47, 3694-3702
+[Vieweg2017a] Vieweg, A. , Influences of continuous austenitizing treatments and different prior microstructures of the austenitic and martensitic state of a 50CrMo4 steel, unpublished
+[Vieweg2017c] Vieweg, A. , Ressel, G. , Prevedel, P. , Marsoner, S. , Ebner, R. , Effects of the Inductive Hardening Process on the Martensitic Structure of a 50CrMo4 Steel, HTM Journal of Heat Treatment and Materials (2017) 72, 3-9
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+Datum, Ort									Unterschrift