• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2005.04a
• /
• pp.225-231
• /
• 2005

In this paper, to prediction of large deformation behavior of steel structures under loading, 3-Dimensional elastic-plastic FE analysis method is developed by using finite deformation theory and proposed cyclic plasticity model. The accuracy of developed analytical method was verified by comparison of experiment result and analysis results using infinitesimal deformation theory. The good agreement between analysis result by developed analytical method and experiment result is shown. Proposed 3-dimensional FE analysis using finite deformation theory and cyclic plasticity hysteresis model can be predict the large deformation of steel members under cyclic loading.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.12
• /
• pp.37-43
• /
• 2004

The performance of magnetic abrasive finishing fur surface is evaluated by the characteristic curve. The characteristic curve is generated by experiment in surface finishing. For experiment, new magnetic inductor is designed and manufactured. 15 kinds of powders are provided to find the relationship between powder characteristic and finishing performance. As powder, Fe-TiC. Polymer-TiC and Fe-NbC are used with different size. The size of abrasives and location are also important factor for the performance. From characteristic curve, two index are obtained, which specify the initial finishing performance and endurance of finishing performance. It is proved that the performance index can be applied to select proper powder for efficient deburring. It is shown that the characteristic curve can be used as good tools for evaluating powder performance in surface finishing and deburring.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.05a
• /
• pp.379-384
• /
• 2007

In this paper, a new method for detecting rotor vibrations in a squirrel-cage induction motor is proposed. The air-gap flux variation analysis was done using search coils inserted in stator slots when rotor vibration conditions occurs. An accurate modelling and analysis of air-gap flux variation in the induction motor are developed using finite-element (FE) software packages, and treasuring the flux are made using search coils. In the FE analysis and experiment, the three-phase squirrel-gage induction motor with 380 [V], 7.5 [kW], 4 Poles, 1,768 [rpm] ratings is used. The simulation and experiment results can be useful for detecting rotor vibration of the induction motors.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2002.11a
• /
• pp.71-77
• /
• 2002

The Production of fine wire through wet wire drawing process with appropriate pass schedule would be impossible without understanding of relationship among many process parameters. Therefore, this paper investigates the relationship among process parameters of wet wire drawing process. In this study, it is possible to obtain the important basic data that can be used in the pass schedule of multi-pass wet wire drawing process. In order to verify the effectiveness of the analysis, pass redesign was performed based on the result of analysis to reduce the wire breakage. The wire breakage between the conventional pass schedule and the redesigned pass schedule was compared by the FE analysis and the wet win drawing experiment.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.10a
• /
• pp.338-341
• /
• 2004

The dimension of forged part is different with the die dimension by the various effects, such as, elastic deformation and thermal effect. And, the difference amounts are not same according to the forging conditions, for example, forging mode, flow stress, etc. Therefore, the use of FEA is effective to predict and update the required die dimension. However, the variables for FE simulation are also as many as variables in the experiment. The variables give very much effect to the accuracy of FE results. At first, the material model is very deeply affected to the estimated dimension of forged part. And the considering of loading and ejecting stages is also important to increase the dimensional accuracy. The experiment and FEA are performed to investigate the dimensional changes and accuracy in cold forging. Two types of upsetting are used to survey the effects of forging mode and stages.

• Transactions of Materials Processing
• /
• v.19 no.4
• /
• pp.242-247
• /
• 2010

In the multi-pass shape drawing process, it is important to design the intermediate dies for producing sound products. Up to now, the design of the intermediate dies is mainly carried out by the industrial experts based on their experience. In this study, a design program was developed to design the intermediate dies for multi-pass shape drawing process. The program was programmed by using VisualLISP. In this program the intermediate dies can be designed by using the initial material shape and the final product shape. In order to verify the effectiveness, the program was applied to design the intermediate dies of multi-pass shape drawing for producing four teeth spline and gun slide. Finally, FE analysis and shape drawing experiment were performed to verify the effectiveness of the designed intermediate dies. As a result, it was possible to produce the drawn products with the required dimensional accuracy.

• Transactions of Materials Processing
• /
• v.9 no.1
• /
• pp.43-51
• /
• 2000

The die wear is one of the main factors affecting product accuracy and die life in hot forging process. It is desired to analyze die wear by developing wear prediction method combined with FE-simulatin and experiment. Lots of researches have been done into the wear analysis of cold forging die, and the results of those researches were successful, but there have been little applications to hot forging die giving successful results. That is because hot forging process has many factors influencing die wear, and there was not accurate in-process data. In this research, change of die surface hardness by thermal softening during the lifetime was obtained by experiment, and hardness distribution of cross section was measured. This wear analysis was applied to hot forging die, and gave comparatively good results compared with actual wear profile.

• Journal of the Korean Society of Tobacco Science
• /
• v.10 no.2
• /
• pp.99-107
• /
• 1988

Pot experiment was conducted to find out the effect of lime application on yield and chemical composition of burley tobacco in 1986, Lime increased exchangeable calcium and pH of soil, but decreased Al, Fe and Mn concentrations. Yield was increased by lime application, however lime could not be caused to yield increasing in the soil with high calcium contents. Cored leaves of limed Plot contained higher Mg. K, total nitrogen, NO3-nitrogen, water soluble and insoluble ash, alkalinity number of water soluble and insoluble ash, citric and malic acid, but lower Fe, Mn, protein-nitrogen, NH3-nitrogen, nicotine petroleum ether extract, palmitic and linolenic acid concentrations than those of unlined plot. The linoleic acid and volatile neutral constituents of cured leaves were not affected by liming. Lime increased yield, however it did not affect leaf duality in respect to chemical characteristics, suggesting that liming should be necessary for tobacco cultivation.

• Journal of Welding and Joining
• /
• v.22 no.2
• /
• pp.28-32
• /
• 2004

Fatigue life at seam weldment of thick plate was estimated using the finite element and FEM-FAT(an exclusive fatigue solver). Finite element meshing at toe and root of weldment was based oil Radaj's theory. Also, the results of FE analysis were compared with experimental results in the point of Miner's Rule. The results of FE and FEM-FAT analysis were in accord with experimental results within 60% confidence. This result reveals that above techniques is useful in assessment of seam weldment and to be an alternative method instead of an object experiment.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2002.12a
• /
• pp.184-185
• /
• 2002

최신 강자성 메모리 공정과 실리콘 비메모리 공정에서 Co, Ni, Fe 등 천이금속 계열의 증착 조건이 소자의 특성 향상 및 신뢰성 향상을 위하여 중요성이 점점 중요해 지고 있다. 강자성 메모리(MRAM)의 출현과 함께 Co, Ni, Fe 등의 수십 $\AA$ 두께를 전체 기판에 대해 균일하게 증착할 요구가 생겼다. MRAM에 요구되는 자기저항특성은 이러한 박막의 수 $\AA$ 두께 변화에 급격히 변화할 수 있으므로[1,2] 원하는 두께로 균일하게 증착 할 수 있는 기술의 확보가 필요하다[3]. (중략)