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송민철(M. C. Song),김대순(D. S. Kim) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.5
The purpose of this study is to design the proper preform for TR forging, a closed-die forging process in order to secure the dimensional accuracy of the forged crank throw under the same material volume, die and forging load. Considering the kinematic characteristics of TR device and the target forged shape of crank throw, the analytical design of preform could have a various choice of geometry variables such as the pin diameter of preform, volumeallo cation and angle between pin and web of preform. The effect of the geometry variables on the dimensions of the crank throw was evaluated by using FEA in order to determine the geometry detail of the preform. According to FEA results, it can be concluded that the pin of the preform should be controlled as same as volume of the pin of the final product. The web diameter of preform should be also maximized as far as the web length of the preform should be controlled smaller than the web thickness of the target forged crank throw.
송민성 ( Song¸ M. S ),심성택 ( Shim¸ S. T ),이광수 ( Lee¸ K. S ),신성우 ( Shin¸ S. W ) 한국구조물진단유지관리공학회 2001 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.5 No.2
Most period code formulas for the RC moment resisting frame building are empirical formulas. Code formula is developed by the measured period of the low-medium buildings during the 1971 San Fernando Earthquake. But measured periods are insufficient to assure the reliability of its accuracy and safety. This paper improves the code formula by regression analysis of the measured period data. Seismic coefficient using the improved formula is evaluated and also compared with those of being based on the current code formula.
유압프레스의 파워 곡선을 고려한 열간 단조 공정의 하중 예측
송민철(M. C. Song),권일근(I. K. Kwon),유지훈(J. H. Yoo),문영훈(Y. H. Moon) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.5
The purpose of this study is to predict quantitatively the forging load of a large forged product using the power curve of hydraulic press. In previous forging analysis, it has been assumed that the die speed is constant during the forging process. However the die speed of hydraulic press is actually defined with the power curve, the relationship between die speed and press load. The change of strain rate having a direct relationship with the die speed affects the forging load. So it is necessary to consider the power curve to predict the forging load. In this study,the power curve was determined by measuring the die speed and press load through the several shop tests. According to FE analysis results, the forging analysis result with the variable die speed by the power curve had a good agreement with a measured final forging load within about 5% deviation, whereas the forging analysis with constant die speed overestimated the measured final forging load about 20%.
송민철(M. C. Song),이용욱(Y. U. Lee),문영훈(Y. H. Moon) 한국소성가공학회 2015 한국소성가공학회 학술대회 논문집 Vol.2015 No.5
The core process in the open die forging for a large crank throw is to bend the preform into the “V” shape blank. The preform could be bended asymmetrically due to its asymmetrical shape, uneven temperature distribution and the misalignment between preform and die. Since the asymmetrically bended blank is very difficult to correct, the proper control method shall be required to prevent it. The purpose of this study is to develop the asymmetry control method in the bending process of preform. Numerical simulation results show that the principal factor controlling asymmetrical forged product is identified as the uneven configuration of preform. The floating die was applied to the bending device to control the asymmetry of preform during bending. The validity of he suggested method was verified by the lab scale experiments.