A one dimensional finite difference diffusion model for simulating the Boost Diffusion Oxidation (BDO) process of titanium alloys is developed and implemented as a window-based program. The program can simulate the BD...
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A one dimensional finite difference diffusion model for simulating the Boost Diffusion Oxidation (BDO) process of titanium alloys is developed and implemented as a window-based program. The program can simulate the BDO process for both constant diffusion coefficient and concentration dependent diffusion coefficient. It is found that to accurately stimulate the BDO process, the concentration dependence of oxygen diffusion has to be taken into account. If the concentration dependence is taken as the Shamblen and Redden's equation, the simulation results agree well with the experimental results.
Numerical simulation of induction heating operations rests on the modelling of Coupled non- linear thermal and magnetodynamic analyses. Strong couplings come from, oil one hand, the power dissipated through Joule effe...
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Numerical simulation of induction heating operations rests on the modelling of Coupled non- linear thermal and magnetodynamic analyses. Strong couplings come from, oil one hand, the power dissipated through Joule effect, and on the other hand, electromagnetic properties that depend on temperature. Usually, ail indirect or staggered method is used to solve Such problems. Several magnetodynamic andthermalsimulations are therefore performed alternatively and sequentially. This paper presents a new method solving thermo-metallurical and magnetodynamic problems together and based on the harmonic balance finite element formulation (HBFEM) of the electromagnetic problem. The temperature and the different harmonics of the Fourier series of the unknown electromagnetic variables are now calculated in a same finite element. An example of the numerical simulation of an induction hardening process is presented. The results obtained with different approaches are compared.
thermal and residual stresses in High-Tensile Strength Steels during weld process are numerically simulated considering phase transformation effect. Fundamental study for the history of thermal stress due to phase tra...
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thermal and residual stresses in High-Tensile Strength Steels during weld process are numerically simulated considering phase transformation effect. Fundamental study for the history of thermal stress due to phase transformation and residual stress during welding heat cycles is Studied in order to investigate the generating mechanism of residual stress and the effects of material properties on stress generation. Two materials of high-tensile strength steels are used in the numerical simulation and experment. Material property of each microstructural phase is used and the time- and temperature-dependant proportion of microstructure are considered by using CCT-diagram in the analysis. thermal stress history obtained by the simulation agrees well with the experimental result during welding heat cycles. Some applications to repair welds and fillet-weld joints of the analytical method are then introduced.
A laser supported process has been developed to modify the electrical andthermal properties of ceramic Substrates locally. This process is characterised by a strong thermal interaction between the laser beam and the ...
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A laser supported process has been developed to modify the electrical andthermal properties of ceramic Substrates locally. This process is characterised by a strong thermal interaction between the laser beam and the ceramic Surface which leads to localised melting. During the dynamic melting process an additional metallic material is introduced. After the solidification a metal-ceramic composite has been generated with different physical properties compared to the non-modified ceramic. The heat and mass transfer during this dynamic inching and solidification process has been Studied experimentally and also numerically in order to identify the dominating process parameters. simulation tools based oil a Finite element model have been developed to describe the heat transfer, fluid flow and the phase change during the melting and solidification of the ceramic. The results of the calculation have been validated against experimental results.
To achieve a higher quality process planning and a more flexible execution of induction hardening computersimulation Of electromagnetic and thermodynamic processes as well as microstructural transformation is recomme...
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To achieve a higher quality process planning and a more flexible execution of induction hardening computersimulation Of electromagnetic and thermodynamic processes as well as microstructural transformation is recommended. This paper describes and suggests an own simulation model of the induction hardening process and explains a special simulation program that has been developed for the Surface induction hardening of axially symmetric steel workpieces. The simulation program performance has been tested by experiments in some cases of high frequency induction hardening cylindrical specimens made of DIN 42CrMo4 steel grade. The measured Values Of Surface hardness and hardening depths have been compared with the simulated values and a good correspondence between simulated and measured values has been obtained.
The rapid densification process is a variant of Chemical Vapour Infiltration. It allows to fabricate composite materials starting from a fibrous preform lying in a boiling hydrocarbon precursor, the cracking of which ...
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The rapid densification process is a variant of Chemical Vapour Infiltration. It allows to fabricate composite materials starting from a fibrous preform lying in a boiling hydrocarbon precursor, the cracking of which results in a solid deposit constituting the matrix of the carbon/carbon composite. A phenomenological analysis emphasises the significant role played by temperature in the couplings between various physical and chemical phenomena. It is shown here that the control of the thermal couplings makes it possible to decrease the power consumed while guaranteeing the quality of the final material.
The computational fluid dynamics approach for high velocity deformation processes as friction welding [1] or friction stir welding can successfully predict certain process aspects including microstructure development,...
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The computational fluid dynamics approach for high velocity deformation processes as friction welding [1] or friction stir welding can successfully predict certain process aspects including microstructure development, if the thermal behaviour is included properly. We model the solid state material flow in the thermomechanically affected zone of the friction stir process using the Navier Stokes equations for an incompressible non Newtonian fluid field representing the ideally plastic material movement. Viscosity is related to the ideally plastic flow stress depending on temperature and strain rate.
Fatigue due to thermal cycling is one of the main reasons for the damage of tools used in die casting processes. In order to investigate the thermal fatigue behaviour of tool steels a thermal fatigue testing facility ...
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Fatigue due to thermal cycling is one of the main reasons for the damage of tools used in die casting processes. In order to investigate the thermal fatigue behaviour of tool steels a thermal fatigue testing facility was designed and built up. For better understanding of the mechanisms of thermal fatigue finite element-simulations were carried out. To specify the cyclic material behaviour push-pull-tests at different temperatures were performed. The Chaboche-model was used to describe the kinematic material response. Isotropic softening is also taken into account. Depending on the arising accumulated plastic strain stable cyclic deformation or continuous softening occurs. The results are consistent with the accomplished thermal fatigue tests on different hot work tool steels.
The development of simulation technology and their benchmark efforts are intensively promoted at many parts of technical and industrial sectors. Beside the investigation in fundamental kinetics, application models and...
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The development of simulation technology and their benchmark efforts are intensively promoted at many parts of technical and industrial sectors. Beside the investigation in fundamental kinetics, application models andsimulation tools database construction is quite important to expand actual usefulness in industrial activity. And also, the misfit of predicted value and actual results should be studied both from model side, database and their difference in input data which are too much simplified than actual operation. Additionally, future expansion in application of computersimulation technologies we need to focus the needs of the future manufacturing technology. In this paper, those problems and future possibility to increase usefulness of simulation work are discussed co-relating experiences with the results of recent benchmark works presented in various conference papers.
Laser forming has become a promising technique to form sheet metal in recent years. This new forming process can produce plastic deformation by thermal stresses resulted from the irradiation of laser beam scanning. In...
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Laser forming has become a promising technique to form sheet metal in recent years. This new forming process can produce plastic deformation by thermal stresses resulted from the irradiation of laser beam scanning. In this paper, a 3-D thermo-mechanical FEM model was developed to simulate the laser forming process of shipbuilding steel plate. The finite-element software MSC. Marc was used to calculate the temperature field, stress field and strain field during laser forming process. The transient temperature field and the final bending angle were predicted. Then the effect of laser forming process technical parameters was studied. To evaluate the accuracy of the simulation, a laser forming experiment was performed. It is demonstrated that the finite element simulation results are in good agreement with experimental results.
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