• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.379-388
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• 1999

Au upper bound elemental technique(UBET) program has been developed to analyze forging load die-cavity filling and optimum kinematically admissible velocity fields for flashless forging. The simulation for flashless forgings are applied plane-strain and axisymmetric closed-die forging with rib-web type cavity. The kinematically admissible velocity fields for inverse triangular and inverse trapezoidal elements are used to analyze flashless forging,. Experiments have been carried out with pure plasticine billets at room temperature. Theoretical predictions of the forging load in plane-strain and axisymmetric forging are in good agreement with experimental results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.5
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• pp.1211-1219
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• 1995

An upper bound elemental technique (UBET) program has been developed to analyze forging load, die-cavity filling and effective strain distribution for flash and flashless forgings. The simulation for flash and flashless forgings are applied axisy mmetric and plane-strain closed-die forging with rib-web type cavity. Inverse triangular and inverse trapezoidal elements are used to analyze flashless forging. The analysis is described for merit of flashless precision forging. Experiments have been carried out with pure plasticine billets at room temperature. Theoretical predictions of the forging load and the flow pattern are in good agreement with experimental results.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.1
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• pp.7-15
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• 1998

An upper bound elemental technique(UBET) program has been developed to analyze forging load, die-cavity filling and effective strain distribution for flash and flashless forgings. The program consists of forward and backward tracing processes. In the forward program, flash, die filling and forging load are predicted. In backward tracing process, the optimum dimensions of initial billet in conventional forging are determined from the final-shape data based on flash design. And the analysis is described for merit of flashless precision forging. Experiments are carried out with pure plasticine billets at room temperature. The theoretical predictions of forging load and flow pattern are in good agreement with the experimental results.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.678-685
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• 1999

A UBET program is developed for determining flash the optimum sizes of preform and initial billet in plane-strain closed-die forging. The program consists of forward and backward tracing processes. In the forward program, flash, die filling and forging load are predicted. In backward tracing process the optimum dimensions of initial billet and preform are determined from the final-shape data based on flash design. Experiments are carried out with pure plasticine billets ar room temperature. The theoretical predictions of forging load and flow pattern are in good agree-ment with the experimental results.

• Transactions of Materials Processing
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• v.28 no.2
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• pp.98-104
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• 2019

The present study numerically simulates the deformation heterogeneity developed in AA1100 during multi-axial diagonal forging (MADF) using finite element analysis (FEA). Diagonal forging type consisting of diagonal forging (DF) and return-diagonal forging (R-DF) proved to be relatively beneficial compared to plane forging type which includes plane forging (PF) and return-plane forging (R-PF) for minimizing the non-uniformity of deformation developed in workpieces. Simulation of the effective strain generated in workpieces during the two types of forging was done using 3-D FEA. FEA shows the effect of friction coefficient on the deformation behavior on workpieces. The simulation of 2 types forging with different friction coefficients revealed that the magnitude of barreling effect and strain heterogeneity in workpieces increases with an increase in the friction coefficient.

• Transactions of Materials Processing
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• v.3 no.2
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• pp.202-214
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• 1994

An upper bound elemental technique(UBET) is applied to predict the forging load and die-cavity filling for non-axisymmetric ring forging. In order to analyze the process easily, it is suggested that the finial product is divided into three different deformation regions. That is axisymmetric part in corner, lateral plane-strain part and shear deformation on boundaries between them. the place-strain and axisymmetric part are combinded by building block method. Also the total energy is computered through combination of three deformation part. Experiments have been carried out with pure plasticine billets at room temperature. The theoretical predictions of the forging load and the flow pattern are in good agreement with the experimental results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.03a
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• pp.63-70
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• 1994

An upper bound elemental technique(UBET) is applied to predict forging load and die-cavity filling for non-axisymmetric ring forging. The finial product is divided into three different deformation regions. That is axisymmetric part in corner, lateral plane-strain part and shear deformation on boundaries between them. The plane-strain and axisymmetric part are combinded by building block method. Also the total energy is computered through combination of three deformation part. Experiments have been carried out with pure plasticine billets at room temperature. The theoretical predictions of the forging load and the flow pattern are in good agreement with the experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.218-223
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• 1993

An UBET(Upper Bound Elemental Technique) program has been developed to analyze forging load, die-cavity filling and effective strain distribution for flashless forging. To analyze the process easily, it is suggested that the deformation is divided into two different parts. Those are axisymmetric part in corner and plane-strain part in lateral. The total power consumption is minimized through combination of two deformation parts by building block method, from which the upper-bound forging load, the flow pattern, the grid pattern, the veocity distribution and the effective strain are determined. To show the merit of flashless forging, the result of flashless and flash forging processes are compared through theory and experiment. Experiments have been carried out with plasticine billets at room temperature. The theoretical predictions of the forging load and the flow pattern are in good agreement with the experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.104-109
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• 1994

This research describes some developments of computer-aided process planning and die design for hot forging products of H-shaped plane strain produced by the press. The system is composed of three main modules(process planning module, die design module and simulation module) which are used independently or in all. Systm capabilities include as follows: 1. In die design module, using the results of process planning module, the shape and size of bolcker and finish die in each operation are determined and the ouput id generated in graphic form for manufacturing drawing. 3. In simulation module, the flow pattern of workpiece and the load/stroke curve are approximately predicted. Design rules for process planning and die design are extracted from plasticity theories, handbooks, relevant references and empirical know-how of field experts in hot forging companies. The developed system provides poweful capabilities for process planning and die design of hot forging products.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.3
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• pp.42-52
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• 1995

An UBET(Upper Bound Elemental Techniquel) program has been developed to analyze forging load, die-cavity filling and effective strain distribution for flashless non-axisymmetric forging. To analyze the process easily, it is suggested that the deforma- tion is divided into two different parts. Those are axisymmetric part in corner and plane- strain part in lateral. The total power consumption is minimized through combination of two deformation parts by building block method, form which the upper-bound forging load, the flow pattern, the grid pattern, the velocity distribution and the effective strain are deter- mined. To show the merit of flashless forging, the results of flashless and flash-forging processes are compared through theory and experiment. Experiments have been carried out with plasticine billets at room temperature. The theoretical predictions of the forging load and the flow pattern are in good agrement with the experimental results.