• Title, Summary, Keyword: End effect

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Experimental Study of the End-plate Gap Effect on the Performance of Extended End-plate Type Splice (이음면 이격이 확장형 단부판 이음부 성능에 미치는 영향에 대한 실험적 연구)

  • Kim, Cheol Hwan;Lee, Myung Jae;Kim, Hee Dong;Kim, Sa Bin
    • Journal of Korean Society of Steel Construction
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    • v.28 no.6
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    • pp.427-438
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    • 2016
  • This study is experimental research for the effect of gap at the end plate on the performance of extended end-plate type splice. For this research, simple beam type specimens by using extended end-plate type splice are planned. Main variables are the initial gap between end-plates, the installation of finger shim plate before the installation of high tension bolts, the final gap between end-plates, and the installation of finger shim plate after the installation of high tension bolts. The static loading tests results show that the maximum bending strength of splice is not dependent on the gap, but the vertical displacement, initial stiffness and elastic stiffness are affected by the gap. In addition to that, the possibility of brittle fracture is increased when the torque of high tension bolt is used to control the gap. Thus, careful consideration is needed in this case.

Prediction of Surface Topography by Dynamic Model in High Speed End Milling (고속 엔드밀 가공시 동적 모델에 의한 표면형상 예측)

  • Lee, Gi-Yong;Ha, Geon-Ho;Gang, Myeong-Chang;Lee, Deuk-U;Kim, Jeong-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.7
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    • pp.1681-1688
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    • 2000
  • A dynamic model for the prediction of surface topography in high speed end milling process is developed. In this model the effect of tool runout, tool deflection and spindle vibration were taken in to account. An equivalent diameter of end mill is obtained by finite element method and tool deflection experiment. A modal parameter of machine tool is extracted by using frequency response function. The tool deflection, spindle vibration chip thickness and cutting force were calculated in dynamic cutting condition. The tooth pass is calculated at the current angular position for each point of contact between the tool and the workpiece. The new dynamic model for surface predition are compared with several investigated model. It is shown that new dynamic model is more effective to predict surface topography than other suggested models. In high speed end milling, the tool vibration has more effect on surface topography than the tool deflection.

Influence of Elastic Restraints and Tip Mass at Free End on stability of Leipholz Column (Leipholz 기둥의 안정성에 미치는 자유단의 탄성구속과 말단질량의 영향)

  • 윤한익;박일주;진종태;김영수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.309-315
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    • 1996
  • An analysis is presented on the stability of elastic cantilever column subjected to uniformly distributed follower forces as to the influence of the elastic restraints and a tip mass at the free end. The elastic restraints are formed by both the translational and the rotatory springs. For this purpose, the governing equations and boundary conditions are derived by using Hamilton's principle, and the critical flutter loads and frequencies are obtained from the numerical evaluation of the eigenvalue functions of this elastic system. The added tip mass increases as a whole the critical flutter load in this system, but the presence of its moment of inertia of mass has a destabilizing effect. The existence of the translational and rotatory spring at the free end increases the critical flutter load of the elastic cantilever column. Nevertheless their effects on the critical flutter load are not uniform because of their coupling. The translational spring restraining the end of cantilever column decreases the critical flutter load by coupling with a large value of tip mass, while by coupling with the moment of inertia of tip mass its effect on the critical flutter load is contrary. The rotatory spring restraining the free end of cantilever column increases the critical flutter load by coupling with the tip mass, but decreases it by coupling with the moment of inertia of tip mass.

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Machining characteristics of micro end-mill using high revolution (고속회전을 이용한 마이크로 엔드밀의 가공특성)

  • Kim, Kisoo;Kim, Sangjin;Cho, Byoungmoo;Kim, Hyeungchul
    • 대한공업교육학회지
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    • v.31 no.2
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    • pp.350-363
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    • 2006
  • Recently, the micro end-milling processing is demanded the high-precise technique with good surface roughness and rapid time in milli-structure parts, micro machine parts and molding industry. The cutting conditions of micro end-milling has an effect on surface roughness of cutting surface. Therefore this study was carried out to cut stainless steel using high revolution air bearing spindle and micro end-mill and analyze the cutting condition to get the optimum surface roughness by design of experiment. From this study, surface roughness have an much effect according to priority on depth of cut, revolution of spindle and feed.

An experimental study on the roundness effect for the cutting conditions in a cylinder cutting by end mill (엔드밀에 의한 원통 가공시 절삭조건에 따른 진원도의 실험적 연구)

  • 박희견
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.8 no.4
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    • pp.52-60
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    • 1999
  • In this study the effect of roundness error with respect to the cutting conditions using the external cylindrical work piece by end mill cutting in a machining center was studied. the end mill used in this study is HSS coated with Ti-N which is of Ø 12-4 flutes. The material of workpiece is SM20C and cutting oil is used as a cooling flued The cutting experiments were carried out for the several cutting conditions(depth of cut height of end mill feed rate revolution per minute and cutting direction) and their roundness effects were compared using the least squares circle measuring method. The experimental results are summarized as follows : 1) The cutting depth is dominant for the roundness of a cylindrical work piece and the cutting speed must be determined precisely when the cutting depth is large 2) When the cutting direction in circular manufacturing is the same with the spindle rotation i.e up-cutting condition the surface roundness is also improved.

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Influence of Elastic Restraint and Tip Mass at Free End on Stability of Leipholz's Column (Leipholz 기둥의 안정성에 미치는 자유단의 탄성구속과 말단질량의 영향)

  • 윤한익;박일주;김영수
    • Journal of KSNVE
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    • v.7 no.1
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    • pp.91-97
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    • 1997
  • An analysis is presented on the stability of an elastic cantilever column having the elastic restraints at its free end, carrying an added tip mass, and subjected to uniformly distributed follower forces. The elastic restraints are formed by both a translational spring and a rotatory spring. For this purpose, the governing equations and boundary conditions are derived by using Hamilton's principle, and the critical flutter loads and frequencies are obtained from the numerical evaluation of the eigenvalue functions of this elastic system. The added tip mass increases as a whole the critical flutter load of the elastic cantilever column, but the presence of its moment of inertia of mass has a destabilizing effect. The existence of the translational and rotatory springs at the free end increases the critical flutter load of the elastic cantilever column. Nevertheless, their effects on the critical flutter load are not uniform because of their coupling. The translational spring restraining the free end of the cantilever column decreases the critical flutter load by coupling with a large value of tip mass, while by coupling with the moment of inertia of tip pass its effect on the critical flutter load is contrary. The rotatory spring restraining the free end of the cantilever column increases the critical flutter load by coupling with the tip mass, but decreases it by coupling with the moment of inertia of the tip mass.

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End Effects of Thin-Walled Beams with General Quadrilateral Cross Sections (일반 사각 단면 형상을 갖는 박판보의 끝단효과에 관한 연구)

  • Kim, Jin-Hong;Kim, Yun-Yeong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.9
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    • pp.2191-2201
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    • 2000
  • End effects due to sectional deformations of thin-walled beams with closed cross section are analysed by a one-dimensional theory. In particular, end effects associated with warping (out of plane m otion) and distortion (in plane motion) are investigated. The exact solutions as a vector form are newly derived to reveal slowly-decaying nature of the end effects in a thin-walled beam loaded by a couple. Several examples of thin-walled beams under various loading conditions indicate that the local end effect zone due to warping and distortion is approximately ten times the typical beam width.

Presumption for Mutual Relation of the End-Milling Condition on Surface Roughness of Al Alloy by Regression Analysis (회귀분석을 이용한 Al 합금의 표면거칠기에 미치는 엔드밀 가공조건의 상관관계 추정)

  • 이상재;배효준;박흥식;전태옥
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.5
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    • pp.46-52
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    • 2003
  • End-milling have been used widely in industrial system because it is effective to a material manufacturing with various shape. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in precision machine part and electronic part. The optimum surface roughness has an effect on end-milling condition such as, cutting direction spindle speed, feed rate and depth of cut, etc. Therefore this study was carried out to presume for mutual relation of end-milling condition to get the optimum surface roughness by regression analysis. The results shown that coefficient of determination($\textrm{R}^2$) of regression equation has a fine reliability of 87.5% and regression equation of surface rough is made by regression analysis.

Molecular Dynamic Study of a Polymeric Solution (I). Chain-Length Effect

  • Lee Young Seek;Ree Taikyue
    • Bulletin of the Korean Chemical Society
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    • v.3 no.2
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    • pp.44-49
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    • 1982
  • Dynamic and equilibrium structures of a polymer chain immersed in solvent molecules have been investigated by a molecular dynamic method. The calculation employs the Lennard-Jones potential function to represent the interactions between two solvent molecules (SS) and between a constituent particle (monomer unit) of the polymer chain and a solvent molecule (CS) as well as between two non-nearest neighbor constituent particles of the polymer chain (CC), while the chemical bond for nearest neighbor constituent particles was chosen to follow a harmonic oscillator potential law. The correlation function for the SS, CS and CC pairs, the end-to-end distance square and the radius of gyration square were calculated by varying the chain length (= 5, 10, 15, 20). The computed end-to-end distance square and the radius of gyration square were found to be in a fairly good agreement with the corresponding results from the random-flight model. Unlike earlier works, the present simulation rsesult shows that the autocorrelation function of radius of gyration square decays slower than that of the end-to-end distance square.

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Evaluation of rigid-end offset effect on seismic behavior of a structure subjected to Van earthquake

  • Bekiroglu, Serkan;Sahina, Abdurrahman;Sevima, Baris;Ayvaz, Yusuf
    • Structural Engineering and Mechanics
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    • v.47 no.6
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    • pp.857-879
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    • 2013
  • Numerical damage assessment of Van train station building consisting of three RC blocks due to 2011 Van Earthquakes by nonlinear dynamic analysis is presented. The structural model is created with rigid-end offsets and plastic hinges for nonlinear analysis. Rigid-end offsets are considered for connection areas and proposed for wall-supported elements. In wall-supported elements, walls take place in a limited part of the columns. Nonlinear dynamic analysis of the building with and without rigid-end offsets is performed by using real earthquake records and results are compared. The results show that rigid-end offsets have significant effects on the seismic behavior of the structures.