• 한국생산제조학회지
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• 제21권1호
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• pp.167-174
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• 2012

For high production rate of parts requiring multiple operations such as punching, blanking, or other operations are generally done with progressive dies. However, progressive die is generally limited to use for sheet metal forming due to the technical difficulties in rod or bulk material. This study proposes a new technique of progressive die and forming process for asymmetric automotive door striker, which is conventionally manufactured with separate tandem processes using solid rod. In order to design forming process and die, FEM simulation was performed to divide proper intermediate processes and analyze its formability. As a result, Forming processes were divided into 3 stages with upper and side punches and also, workpiece feeding and location mechanism was designed and manufactured in this study. Finally, forming tryouts were carried out by using the manufactured progressive die to verify the forming quality and productivity.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2010년도 정기 학술대회
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• pp.211-214
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• 2010

플랫 플레이트 시스템은 기둥 주위의 국부적인 응력집중 현상으로 인한 뚫림전단 파괴에 대해 취약하다. 따라서 유한요소해석을 통해 이러한 플랫 플레이트 시스템의 뚫림전단 성능을 평가하고자 한다. 슬래브의 전단을 고려하기 위하여 Reissner-Mindlin 가정을 바탕으로 한 등매개변수 감절점 쉘 요소를 적용하였다. 콘크리트의 재료적 비선형 거동을 고려하기 위해 압축거동은 수정압축장 이론을 적용하였으며 인장강성효과 또한 콘크리트 재료모델에 반영하였다. 기존 실험결과와의 비교를 통해 타당성을 검증하고자 하였다. 비교 결과, 약 16%의 오차율을 보였으며 보강비가 낮은 실험체에 비해 보강비가 높은 실험체가 실험결과에 가까운 값을 예측하는 것으로 나타났다.

• 콘크리트학회지
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• 제20권2호
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• pp.25-36
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• 2008

Seismic design of reinforced concrete flat plate structures is often complicated as it deals with three dimensionality and continuous spans, and mostly material complexity and reinforcement variation. A great degree of uncertainty in such structural and material properties is thus inherent in the RC flat plate systems, and hinders simplification of the design process in terms of slab flexure, unbalanced moment transfer at a slab-column connection, and punching shear. For these reasons, there have been substantial changes and updates in building codes relating to flat plates and slab-column connections over a handful of decades. Also, for the same reason, some of codes never have been revised. As a consequence of nonsimultaneous development of each provision, it tends to confuse structural engineers when using a mixture of all different US code provisions. In this paper, in the step-by-step logical order, seismic design of the RC flat plate systems is re-organized and clarified to make it easier to apply. Furthermore, recent changes or proposed changes are introduced, and are explained as to how it will apply in practice.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.39-40
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• 2011

The purpose of this study is to select a conductive resistor as high energy efficiency through analysis of the heating properties by induction heating. The result of this study, the heating properties is capable of weaken cementitious joint in 10~30 seconds when using the conductive resistor with wire mesh or punching metal. Although the steel is higher temperature than SUS304, SUS304's heating properties are more uniform.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.3-4
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• 2011

The purpose of this study is to suggest basic data for development optimal disassembly manufacturing system during analysis pore structure and heating properties of cementitious joint using conductive resister by induction heating. From the results, we knew cementitious joint is weak easily by heating of conductive resister, such as wire mesh, punching metal, and steel fiber, from induction heating.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.191-196
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• 2005

A full-bead of multi-layer-steel (MLS) engine head gasket is used to seal the combustion gas. Finite element analyses were conducted to assess the dependence of the sealing performance of full-bead on the forming process consisting of embossing and flatting operations. It is demonstrated that the sealing performance is enhanced with more severe deformation of the bead plate during the embossing, i.e., with the increase in the punching depth, the punch height, the punch width and the friction coefficient of the bead plate against the punch and die, and with the decrease in the width of die cavity. Meanwhile, the flatting process that is employed to adjust the height of the embossed full-bead has no influence on the sealing performance.

• International Journal of Railway
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• 제2권4호
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• pp.131-138
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• 2009

Static tensile and fatigue tests were conducted using tensile-shear specimens to evaluate the fatigue strength of a SPCC sheet clinch joint. The maximum tensile strength of the specimen produced at the optimal punching force was 1750 kN. The fatigue endurance limit (=760 N) approached 43% of the maximum tensile load (=1750 N) at a load ratio of 0.1, suggesting that the fatigue limit is approximately half of the value of the maximum tensile strength. The FEM analysis showed that at the fatigue endurance limit, the maximum von-Mises stress of 373 MPa is very close to the ultimate tensile strength of the SPCC sheet (=382 MPa).

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
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• pp.67-73
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• 1997

By introducing the concept of overpressurization of rim pores due to dislocation punching, the total pressure exerted on the rim pores is estimated. Then this concept is combined with the assumption that all the fission gases produced in the rim region are retained in the rim region to calculate the rim porosity. Rim porosities calculated in this way are compared with measured data, which produces reasonable agreement. Finally a correlation for the thermal conductivity of the rim region is obtained using the hypothesis that the rim region consists of pores and fully dense material of UO$_2$.

• Computers and Concrete
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• 제27권4호
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• pp.297-304
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• 2021

The hybrid Finite-Discrete Element (FDEM) approach combines aspects of both finite elements and discrete elements with fracture mechanics principles, and therefore it is well suited for realistic simulation of quasi-brittle materials. Notwithstanding, in the literature its application for the analysis of concrete is rather limited. In this paper, the proprietary FDEM code ELFEN is used to model concrete specimens under uniaxial compression and indirect tension (Brazilian tests) of different sizes. The results show that phenomena such as size effect and influence of strain-rate are captured using this modeling technique. In addition, a preliminary model of a slab subjected to dynamic shear punching due to progressive collapse is presented. The resulting fracturing pattern of the impacted slab is similar to observations from actual collapse.

• Coupled systems mechanics
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• 제11권3호
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• pp.233-257
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• 2022

This work presents a comparative study between two different models: trapezoidal and T-shaped combined footings. The comparative study between trapezoidal and T-shaped combined footings presented in this paper generatesresultsthat have an unparalleled accuracy for all foundation engineering problems. The main part of this research is to obtain the optimal area, reinforcing steel, and thickness of the trapezoidal and T-shaped combined footings using the new models. The comparison is made for two trapezoidal combined footings and two T-shaped combined footings ofreinforced concrete subjected to the same load.Themain findings are: themodelfortrapezoidal combined footings can be used for rectangular and triangular, and the T-shaped combined footings can be used for rectangular. The structure of the paper is asfollowsfirst a very complete state of the art with extensive referencesthat describesthe methodology used for the different models clearly, presents different numerical examples, results and at the end conclusions.