• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.2
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• pp.17-21
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• 2007

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.128-133
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• 2004

This study has been focused on the development of shear forming process of grid for lead-acid battery. The grid plays an important role in the flow of electricity because the grid is a skeleton of the pasted plate. Therefore, it must be of the highest quality to prevent plate failures and then, battery failure, and ensure the best battery performance possible. The finite element analysis of the shear forming process is carried out and the result is compared with the experimental data. The influence of the numerical parameters such as clearance, velocity of punch and critical damage value on the simulation results turns out to be very considerable.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.86-91
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• 2020

An important factor of rough road modeling is analyzing the shear behavior properties of the rough road. These properties influence the drawbar pull of the tool when interacting with the soil used in agriculture. Furthermore, shear behavior properties are important because sinkage and shear stress are generated when wheels drive on rough roads. In this study, we performed a direct shear test to investigate the shear behavior properties of soils and compare with the direct shear simulation; shear force derived by the coupled analysis of discrete element method; and multi-body dynamics. Soil contact parameters were measured in a wheel and soil contact simulation followed by comparison of the simulated and experimentally measured shear force.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.448-452
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• 2005

Punching/blanking/shearing is among the oldest and most frequently used sheet metal forming process. We have developed the shear device for burrless cutting using the micro wire. Since the burr minimization and fine shear plane, this paper is a study on the effect of the shear angle and clearance of the cutter-cutter. And, we confirm the tendency of the shear plane. It is impossible to completely remove the burr in the shearing process. In order to minimize the burr size and fine shear plane, we have accomplished the various experiment conditions such as the shear angle and clearance. Despite the quality of shear plane is not good enough yet, it is possible to make the burr minimization and fine shear plane by the optimization of process parameters.

• Transactions of Materials Processing
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• v.14 no.1 s.73
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• pp.37-42
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• 2005

In order to invstigate the influence of die design variables on the quality of the sheared surface in cutting of sandwich sheet metals, the cut-off operation is carried out, which is the typical shearing process in sheet metal forming technology. For experiments we made the cut-off die which can be easily adjusted for die design variables such as blankholding force, pad force and clearance. The sandwich sheet metals considered are clad304(STS304-Al1050-STS304) and anti-vibration sheet metal. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results it is shown that the shearing mechanisms are different according the material of which sandwitch sheet metal is composed. The influence of die design variable is explored and we found optimal conditions for both sandwich sheet metals. It is expected that this investigation can be utilized to get the better sheared surface.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.57-61
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• 2004

in order to improve the quality of the sheared surface in cutting of sandwich sheet metals the cut-off operation is mainly investigated which is the typical shearing process in sheet metal forming technology. For experiments the cut-off die is made which can be easily adjusted by die design variables such as blankholding force, pad force, and clearance. The sheet metals chose as specimen are clad304(STS304-Al1050-STS304) and anti-vibration sheet metal. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface before and after cut-off operation is measured and quantitatively compared with the help of the optical microscope. From test results the good sheared surface was shown when the clearance gets small with large blankholding force.

• Composites Research
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• v.30 no.3
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• pp.193-201
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• 2017

Molecular dynamics simulation and the Mori-Tanaka micromechanics study are performed to investigate the effect of the covalent grafting between CNT and polyester on the mechanical behavior and load transfer of nanocomposites. The transversely isotropic stress-strain curves are determined through the tension and shear simulations according to the covalent grafting. Also, isotropic properties of randomly dispersed nanocomposites are obtained by orientation averaging the transversely isotropic stiffness matrix. By addressing the grafting, the transverse Young's modulus and shear moduli of the nanocomposites are improved, while the longitudinal Young's modulus decreases due to the degradation of the grafted CNT.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.119-125
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• 1982

Using piston type extruder, barley flour was extruded at various processing conditions, The used variables were three shear rates (apparent shear rate 118, 534, $1169sec^{-1}$), four extrusion temperatures(90, 120, 150, $180^{\circ}C$) and three moisture contents (15, 25, 35%). The rheological properties and the extrudate quality were monitored in extrusion. Barley flour showed pseudoplastic behavior having average power law index 0.28 in used shear rate range. When viewed from general appearance, die swell, density, water uptake, rehydration swell and gelatinization degree of extrudate, $25{\sim}35%$ moisture and $120^{\circ}C$ temperature was suitable processing condition for noodle-like product, and 25% moisture and $150^{\circ}C$ temperature was good for snack or flake product. Moisture content of the extrudate can be pretty well estimated from energy balance at higher temperature and higher moisture content.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.512-512
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• 2008

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.97-97
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• 2010

최근 자동차에서 경량화의 방안으로써 높은 강성을 요구하는 고장력강 사용이 증대 되고 있다. 그러나 고장력강은 저항 점용접 시 일반 강에 비해 높은 전류를 요구하며 계면파단 및 expulsion 발생이 용이하기 때문에 가용 전류 구간이 좁은 특성을 가진다. 많은 연구자들이 hold time, tempering 등의 process를 이용하여 고장력강의 저항 점용접성을 개선하고자 하였으나 생산 공정라인에 적용하기는 어려운 실정이다. 본 연구에서는 용접 공정 변수의 변화에 따른 용접성과 전극 형상 변화을 통한 고장력강 점 용접성 향상에 대한 연구를 실시 하였다. 고장력강의 점 용접성 비교하기 위해 표준 전극(S1)과 인위적으로 가공한 전극(M1)을 사용하였으며, 실험에 사용된 판재는 두께 1.4mm의 DP590이며, 그 결과 표준전극(S1) 보다 가공 전극(M1)의 가용 전류 구간이 0.5kA 정도 넓은 것으로 확인 되었다. 두 전극을 사용한 점용접 시험편들의 인장전단강도를 비교 해보면 표준전극(S1)을 적용한 점용접 시 인장전단강도는 KS B 0850 기준에 만족하나 계면 파단이 발생 하였다. 가공 전극(M1)을 적용한 점용접 시 인장전단강도는 규격 기준에 만족하나 버튼 파단이 발생 하였다. 두 전극을 적용한 점용접부 형상 및 용접부 온도 분포에대해 저항점용접 시뮬레이션 프로그램(SORPAS)을 이용하여 실험 결과 값과 비교 분석하였고 파단모드의 변화에 대한 원인 분석을 도출 하였다.