A Study on Formation Process of Secondary Upsetting Defect in Electric Upsetting and Optimization of Processing Parameters Based on Multi-Field Coupling FEM
Abstract:The electric upsetting process is an excellent electrically assisted preforming technique with electrical-thermal-mechanical multi-field coupling characteristic. The secondary upsetting defect in electric upsetting with inappropriate parameters combinations could result in folds in subsequent forging process. In order to analyze the formation process of the secondary upsetting defect, the finite element model of electric upsetting was constructed based on the multi-field coupling solver platform, MSC. Marc. It… Show more
“…Therefore (21) follows from (30) and (31). Finally, to prove (22) we estimate each term on the right-hand side of (23). Let H ∈ H 2 −1 (Ω), we bound the first term by applying a Poincaré-type inequality…”
Section: Convergencementioning
confidence: 99%
“…In particular, this paper is motivated by the study of the electromagnetic behavior of a steel bar submitted to a preforming process called electro-upsetting. This process, which actually requires a multiphysics model [21,22], consists in passing a current through a cylindrical bar which is heated by Joule effect and then to deform it to a particular shape; see, for instance Fig. 1.…”
The aim of this paper is to study the numerical approximation of an axisymmetric time-harmonic eddy current problem involving an in-plane current. The analysis of the problem restricts to the conductor. The source of the problem is given in terms of boundary data currents and/or voltage drops defined in the so-called electric ports, which are parts of the boundary connected to exterior sources. This leads to an elliptic problem written in terms of the magnetic field with nonlocal boundary conditions. First, we prove the existence and uniqueness of the solution for a weak formulation written in terms of Sobolev spaces with appropriate weights. We show that the magnetic field is not the most appropriate variable to impose the boundary conditions when Lagrangian finite elements are used to discretize the problem. We propose an alternative weak formulation of the problem which allows us to avoid this drawback. We compute the numerical solution of the problem by using Lagrangian finite elements ad hoc modified on the vicinity of the symmetry axis. We provide a convergence result under rather general conditions. Moreover, we prove quasi-optimal order error estimates under additional regularity assumptions. Finally, we report numerical results which allow us to confirm the theoretical estimates and to assess the performance of the proposed method in a physical application which is the motivation of this paper: the computation of
“…Therefore (21) follows from (30) and (31). Finally, to prove (22) we estimate each term on the right-hand side of (23). Let H ∈ H 2 −1 (Ω), we bound the first term by applying a Poincaré-type inequality…”
Section: Convergencementioning
confidence: 99%
“…In particular, this paper is motivated by the study of the electromagnetic behavior of a steel bar submitted to a preforming process called electro-upsetting. This process, which actually requires a multiphysics model [21,22], consists in passing a current through a cylindrical bar which is heated by Joule effect and then to deform it to a particular shape; see, for instance Fig. 1.…”
The aim of this paper is to study the numerical approximation of an axisymmetric time-harmonic eddy current problem involving an in-plane current. The analysis of the problem restricts to the conductor. The source of the problem is given in terms of boundary data currents and/or voltage drops defined in the so-called electric ports, which are parts of the boundary connected to exterior sources. This leads to an elliptic problem written in terms of the magnetic field with nonlocal boundary conditions. First, we prove the existence and uniqueness of the solution for a weak formulation written in terms of Sobolev spaces with appropriate weights. We show that the magnetic field is not the most appropriate variable to impose the boundary conditions when Lagrangian finite elements are used to discretize the problem. We propose an alternative weak formulation of the problem which allows us to avoid this drawback. We compute the numerical solution of the problem by using Lagrangian finite elements ad hoc modified on the vicinity of the symmetry axis. We provide a convergence result under rather general conditions. Moreover, we prove quasi-optimal order error estimates under additional regularity assumptions. Finally, we report numerical results which allow us to confirm the theoretical estimates and to assess the performance of the proposed method in a physical application which is the motivation of this paper: the computation of
“…In this study, according to the explanations of the crankshaft design cycles, in the previous chapter and the (5)…”
Section: Designing the Crankshaft Preformmentioning
confidence: 99%
“…In recent years, significant efforts have been made to develop some new methods including FE method (FEM) and intelligent control system to optimize upsetting process. Quan et al [1] Sukjantha et al [2], Nuasri et al [3], Jeong et al [4], and Quan et al [5] analysed the influence of processing parameters on the upsetting process, predicted an optimum process condition, determined an optimal preform part and saved the secondary upsetting defect, respectively by FEM. Liu et al [6] introduced a new computer-controlled upsetting system and solved the underfill defect in next hot forging.…”
Crankshafts are among the most important parts in internal combustion engines, of which stirling engine is a useful example. Manufacturing process of a crankshaft, is considered as a three-step forging process using preform, due to the complexity in geometry. The most challenging step of the multistage forging process is to avoid stress concentration and to create uniformity of strain by controlling metal flow. In the present study, the final part was achieved under three manufacturing processes namely: upsetting, hot and cold forging. The models used in each manufacturing process are designed by CATIA software. A finite element simulation on the basis of Cockcraft-Latham damage criterion was developed in DEFORM software. Using experiment design by Taguchi method, The optimization of manufacturing processes were carried out by MINITAB software in two steps, in which the optimization objectives are considered as force, damage and strain uniformity, and; input variables are taken as part-mold friction, pressing velocity and process temperature. In order to find the most effective parameter of each manufacturing process, analysis of variance was conducted on the results, in which, the most effective parameters in the upsetting, hot and cold forging processes were temperature, friction and temperature, respectively.
“…Hu et al used multistage upsetting to form a relatively large diameter flange on the end of a pipe [10]. Quan et al also studied the multistage upsetting process [11]. They examined the formation of overlap in the electric upsetting of an engine valve.…”
This paper presents the results of a numerical analysis of a cold forging process for a hollow flanged part. The analysis was performed using Deform 2D/3D. 42CrMo4 steel tubes were used as the billet material, and their material model in the annealed state was described by a constitutive equation. The forming process was performed in six stages with the use of methods such as extrusion with a movable sleeve, open-die extrusion, and upsetting. The objective of the study was to determine whether the proposed forging technique could be used to produce hollow parts with flanges. The determination was made based on the analysis of product geometry quality and process parameters, including the Cockcroft-Latham ductile fracture criterion and forming forces.
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