• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.191-195
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• 1996

Conventional single-side straight cutting of sheet metal is analyzed by the rigid-thermoviscoplastic finite element method. The FE-simulation is performed from initial stage to final stage of shearing process. The ductile fracture criterion and element kill method are used in the present work to estimate if and where a fracture occurs and to investigate the features of sheared surface in shearing process. The FE-simulation results are obtained for different clearances and these are compared with published experimental results. It is found that the results of the present work are in close agreement with published experimental results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.229-234
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• 1994

The major objective of the present paper is to estabilish finite element simulation technique in order to further analyze the shearing process. For this the ductile fracture criterion and element kill method are used in the present work. It is postulated that a fracture initiation is based on the magnitude of local effective strain. The features of sheared surface are easily observed by the element kill method. The simulation results are compard with existing experimental results. It is found that the results of the present work are close agreement with the existing results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.598-602
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• 1996

This study is performed for investigating the effects of stripping and counter punching force on shearing characteristics in fine blanking, such as camber, burr-height and dimensional accuracy, etc by experiments. Conventional hydraulic press equipped with specially designed hydraulic unit is used for experiments so that both the stripping force and counter punching force are arbitrarily adjusted according to experimental conditions. Two kinds of materials, hot rolled steel sheet(1mm, 3mm) and pure aluminum(1mm, 3mm) are selected in order to examine the influence of strength and thickness of working materials in blanking of T-shaped products. Based on the experimental results of this study, it can be concluded that the finely cut surface of sheared blank can be obtained even in conventional hydraulic press if additional equipments and special dies are employed.

• 한국정밀공학회지
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• 제25권7호
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• pp.64-71
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• 2008

Burr generated on plate holder should be removed through additional process, because it has an influence on the function of automotive seat recliner. The process layout to perform simultaneously embossing and half blanking of plate holder has been developed in this study in order to minimize the influence of burr formation. The optimal process condition to satisfy the required dimensional accuracy of plate holder has been determined using Taguchi method and finite element analysis. It has been shown from experimental results that the proposed method is decidedly superior to the previous FCF method from the aspect of sheared surface, roll-over, flatness and burr height.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.409-412
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• 2009

A study is made to put forward the new method of continuous-shear drawing (CSD), and investigate deformation behavior and microstructure evolution of aluminum alloy with a comparison of equal-channel angular (ECA) drawing. In contrast to ECA drawing, the die for CSD deformation can impart an additional strain to the workpiece since the diameter of the exit channel is narrower than that of its entrance channel. Although no significant crack occurs in all conditions during deformation, the sample deformed via CSD method showed better surface quality as compared to ECA drawing. This is mainly ascribed to the fact that the sample is significantly bent rather than sheared when deforming through ECA drawing.

• 태양에너지
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• 제20권4호
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• pp.53-60
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• 2000

An experimental study was carried out in a cavity with upper channel and square heat surface by visualization equipment with Mach-Zehnder interferometer and laser apparatus. The visualization system consists of 2-dimensional sheet light by Argon-Ion Laser with cylindrical lens and flow picture recording system. Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system(CACTUS'2000). Obtained result showed various flow patterns. Severe unsteady flow fluctuation within the cavity are remarkable and sheared mixing layer phenomena are also found at the region where inlet flow is collided with the counter-clockwise rotating main primary vortex. Photographs of Mach-Zehnder are also compared in terms of constant heat flux.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.805-810
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• 1997

In this paper the technique to predict tool were theoretically in the sheet metal shearing process is suggested. The were in sheet metal tool affects the tolerances of final parts, metal flows and costs of processes. In order to predict the tool were the deformation of workpiece during the process is analyzed by using non-isothermal finite element program. The ductile fracture criterion and the element kill method are also used to estimate if and where a fracture will occur and to investigate the features of the sheared surface in shearing process. Results obtained form finite element simulation such as node velocities and node forces are transformed into sliding velocity and normal pressure on tool monitoring points respectively. The monitoring points are automatically generated and the were rates on these points are accumulated during a process. It is assumed that the wear depth on the tool surface are linear function of the lot sizes based upon the known experimental results. The influence of clearance between die and punch upon tool wear is were is also discussed during the process.

• 한국기계가공학회지
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• 제15권2호
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• pp.22-30
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• 2016

It is very important to obtain the net shape of the product to maximize the shear cutting surface of fine blanking. In this paper, the fine blanking die was manufactured to achieve part characteristics, such as flatness and a fully sheared surface. The V-ring in the fine blanking die was designed to prevent lateral movement of the material. The fine blanking experiment was conducted with the fine blanking die. The material usage rate was increased by over 5.7% and that of the water-soluble lubricant was decreased by over 33% when the 2-cavity die technology was applied to fine blanking. The capacity of the existing press could lead to productivity improvement and cost reduction. Thus, 2-cavity die technology for fine blanking with a minute module of an accurate gear for producing seat recliner parts was developed.

• 터널과지하공간
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• 제13권1호
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• pp.64-75
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• 2003

본 연구에서는 2001년 Bakers와 Stephansson이 제안한 Punch Through Shear Test를 소개한다. 본 연구의 목적은 대전화강암을 사용하여 이 시험법이 암석의 전단 모드 파괴 인성 측정법으로서의 적합성을 알아보는 것이다. 또한, 전단모드 파괴인성을 구하기 위한 최적의 시료형상을 결정하고 전단모드 파괴인성과 봉압과의 관계를 규명하였다. 시험결과, 인장 파괴에서와 같이 거친 파괴면이 형성되지 않고 전단을 받았음을 알 수 있는 부드러운 파괴면이 관찰되었다. 시료형상에 대한 연속체 해석과 입자유동 해석 그리고 균열전파 시뮬레이션을 수행한 결과 시료내부에서 일어나는 균열의 발생은 주로 전단모드이고 이러한 전단균열들로 인해 시료의 파괴가 발생함을 입증할 수 있었으며, 결과적으로 Punch Through Shear Test는 암석의 전단모드 파괴인성 측정법으로서 적합함을 입증할 수 있었다.

• 동력기계공학회지
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• 제20권6호
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• pp.40-45
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• 2016

The manufacturing process of large scaled Al 7050 alloy is difficult for the occurrence of solidification crack during casting. The aims of this study are the evaluations of microstructure and mechanical properties of extruded Al 7050 billet and ring forged one with large scale. Large scaled Al 7050 billet was casted by direct-chill casting process. The extruded and ring forged specimens were prepared from the casted ingot after residual stress relief and homogenization heat treatment, respectively. Microstructures, hardness and tensile test of the surface, middle and center part of each specimen were performed at room temperature. Sheared and elongated type grains were observed at the edge parts of surface and center area and its aspect ratios of grains were low and similar as 0.21 while that of middle area was closed to 0.92 value in ring forged Al 7050 alloy. The mechanical properties of extruded Al 7050 alloy were superior than those of ring forged one. The hardness values of surface and center part were slightly higher than that of middle part in ring forged Al 7050 alloy.