Some Plastic Deformation Modes for Indentation of Half Space by a Rigid Body With Serrated Surface as a Model of Roughness Transfer in Metal Forming

2002 ◽  
Vol 124 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Jingyu Shi ◽  
D. L. S. McElwain ◽  
S. A. Domanti

This paper is concerned with the plastic deformation modes of the free surface of the half space between the teeth on the serrated surface of a rigid body. The rigid body indents the half space perpendicularly and the material of the half space is assumed to be elastic/rigid perfectly plastic. Plane-strain conditions are assumed. The emphasis in this paper is on the profile left on the surfaces of the material when the indentation proceeds to some depth and then the indenter is removed. Based on the observations from finite element results, slip line fields for the plastic deformation regions at various stages of indentation are proposed and the corresponding hodographs for the velocity field are presented. This has application in roughness transfer of final metal forming process.

2013 ◽  
Vol 773-774 ◽  
pp. 115-118
Author(s):  
Andrzej Gontarz

This paper presents results of theoretical and experimental research works on metal forming process of a hub. A typical technology of forging on hammer of this part with flash was discussed. Two new processes of a hub forging were proposed, characterized by large material savings in comparison with typical technology. The first process is based on forming without flash of a forging with axial cavity. The second one is connected with forming of forging from pipe billet. The realization of these processes is possible at the application of a press with three movable working tools. Theoretical research works were done on the basis of simulations by means of finite element method. Simulations were made mainly in order to determine kinematics of material flow in forging processes and precision of shape and dimensions of obtained products. The first of the proposed processes was experimentally verified and a product of good quality was obtained. Material consumption of the analyzed processes and other factors acting on their effectiveness were also compared.


Metal forming process is a widely used manufacturing process especially in high volume metal production system. In this paper, the main objective is using Bubnov-Galerkin finite element model to derive the pressure field set up at various cross-sections of a metal blank during a forging process, and the four Lagrange quadratic elements were assembled to represent the various metal blank. The governing equation adopted for this paper is a one-dimensional differential equation describing the pressures exerted on the forging process. During the analysis, the various metal blanks are divided into a finite number of elements and the weighted integral form for each element were formed after applying the Bubnov-Galerkin weighted residual method. A matrix form under certain boundary conditions from the weighted residual method were used to obtain the pressure distribution across the cross-section of the various metal blanks. Finite element results are obtained for a value of a circular disc diameter, thickness, coefficient of friction, principal stress, length, and radius of a circular material. Finite element method and the Exact solution approach are used to achieve and compare both results. Furthermore, the combination of both methods shows that there are potentials for using this approach towards the optimization of metal forming in manufacturing processes and some engineering practices. Keywords: Forging; LaGrange Interpolation Function; Bubnov-Galerkin Weighted Residual Method; Finite Element Method.


2011 ◽  
Vol 704-705 ◽  
pp. 674-679
Author(s):  
Dan Xia ◽  
Bin Shi Xu ◽  
Yao Hui Lv ◽  
Yi Jiang ◽  
Cun Long Liu

With considering the Marangoni convection in the molten pool on plasma direct metal forming process, a finite element model posed to describe and reflect the flow in the molten pool. Results of temperature distribution modeling prepared by plasma direct metal forming process of metal powders in an Ar environment were numerically obtained and compared with experimental data. Powders of Fe314 and base plates of R235 steel were taken as sample materials. In the experiment a multi-stream nozzle capable of delivering metal powder coaxially with the plasma arc was used. The model revealed that the velosity of the front part of the pool is a little slower than aft part. Marangoni convection reinforced the convection and enhanced the heat transfer. Profile of the model is the same as the experimental data. This allows us to conclude that the model can be applied for preselecting the process parameters. Keywords: plasma, rapid forming, temperature field, Marangoni convection.


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