Application of FEM Modeling to Simulate Metal Flow in Forging a Titanium Alloy Engine Disk

1983 ◽  
Vol 105 (4) ◽  
pp. 251-258 ◽  
Author(s):  
S. I. Oh ◽  
J. J. Park ◽  
S. Kobayashi ◽  
T. Altan

The isothermal forging of a titanium alloy engine disk is analyzed by the rigid-viscoplastic finite element method. Deformation mechanics of the forging process are discussed, based on the solution. The effects of temperature and heat conduction on the forging process are also investigated by coupled thermo-viscoplastic analysis. Since the dual microstructure / property titanium disk can be obtained by controlling strain distribution during forging, the process modeling by the finite element method is especially attractive.

Author(s):  
Shiro Kobayashi ◽  
Soo-Ik Oh ◽  
Taylan Altan

The application of computer-aided design and manufacturing techniques is becoming essential in modern metal-forming technology. Thus process modeling for the determination of deformation mechanics has been a major concern in research . In light of these developments, the finite element method--a technique by which an object is decomposed into pieces and treated as isolated, interacting sections--has steadily assumed increased importance. This volume addresses advances in modern metal-forming technology, computer-aided design and engineering, and the finite element method.


Author(s):  
Shiro Kobayashi ◽  
Soo-Ik Oh ◽  
Taylan Altan

A majority of the finished products made by metal forming are geometrically complex and the metal flow involved is of a three-dimensional nature. Thus, any analysis technique will become more useful in industrial applications if it is capable of solving three-dimensional metal-flow problems. Nagpal and Altan introduced dual-stream functions for describing metal flow in three dimensions. This work showed that the proper selection of a flow function makes the incompressibility requirement automatically satisfied and provides general kinematically admissible velocity fields. Yang and Lee utilized the conformal transformation of a unit circle onto a cross-section in the analysis of curved die extrusion. They derived the stream-line equation from which a kinematically admissible velocity field was determined. The upper-bound method was then applied to determine the extrusion pressure for a rigid-perfectly plastic material. An important aspect of three-dimensional plastic deformation is the analysis of spread in metal-forming operations, such as spread in rolling or in flat tool forging, and spread in compression of noncircular disks. Solutions to such problems have been obtained by the use of Hill’s general method and the upper-bound method. The extension of the finite-element method to solve three-dimensional problems is natural and not new, particularly in the area of elasticity. However, the simulation of three-dimensional forming operations by the finite-element method is relatively recent. Park and Kobayashi described the formulation for the three-dimensional rigid-plastic finite-element method and the implementation of the boundary conditions. They applied this technique to the analysis of block compression between two parallel flat platens. For certain forming problems, such as those involving lateral spread, the use of a simplified three-dimensional element is efficient and some examples can be found for analysis of spread in rolling and flat tool forging. The matrices for evaluation of elemental stiffness equations are defined for a three-dimensional brick element in Chap. 6 and some of them are recapitulated in this section. A three-dimensional brick element used for the analysis is an eight-node hexahedral isoparametric element.


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