• Title, Summary, Keyword: Slip Line Field

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Determination of stress state in chip formation zone by central slip-line field

  • Andrey Toropov;Ko, Sung-Lim
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.577-580
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    • 2003
  • Stress state of chip formation zone is one of the main problems in metal cutting mechanics. In two-dimensional case this process is usually considered as consistent shears of work material along single of several shear surfaces. separating chip from workpiece. These shear planes are assumed to be trajectories of maximum shear stress forming corresponding slip-line field. This paper suggests new approach to the constriction of slip-line field, which Implies uniform compression in chip formation zone. On the base of given model it has been found that imaginary shear line in orthogonal cutting is close to the trajectory of maximum normal stress and the problem about its determination have been considered. It has been shown that there is a second central slip-line field inside chip, which corresponds well to experimental data about stress distribution on tool rake face and tool-chip contact length. The suggested model could be useful in solution of various problems of machining.

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Determination of stress state in formation zone by central slip-line field chip

  • Toropov Andrey;Ko Sung Lim
    • International Journal of Precision Engineering and Manufacturing
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    • v.6 no.3
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    • pp.24-28
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    • 2005
  • Stress state of chip formation zone is one of the main problems in metal cutting mechanics. In two-dimensional case this process is usually considered as consistent shears of work material along one of several shear surfaces, separating chip from workpiece. These shear planes are assumed to be trajectories of maximum shear stress forming corresponding slip-line field. This paper suggests a new approach to the constriction of slip-line field, which implies uniform compression in chip formation zone. Based on the given model it has been found that imaginary shear line in orthogonal cutting is close to the trajectory of maximum normal stress and the problem about its determination has been considered as well. It has been shown that there is a second central slip-line field inside chip, which corresponds well to experimental data about stress distribution on tool rake face and tool-chip contact length. The suggested model would be useful in understanding mechanistic problems in machining.

A study on the sheet drawing using the Matrix method (Matrix법을 이용한 판재 인발에 관한 연구)

  • 유홍균;전병희
    • Journal of the korean Society of Automotive Engineers
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    • v.13 no.6
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    • pp.90-100
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    • 1991
  • This paper represents the analysis of the sheet drawing by applying the Matrix method to Hill's slip-line field for small reduction and indirect type slip-line field in case of large reduction. Results of the analysis represent the relation between the reduction ratio and the die wall pressure, mean drawing stress through rough die. The limitation on the use of this slip-line field is described. When the reduction ratio is given, the optimum die angle is analyzed in this paper.

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Fully Plastic Analyses of Unequally Notched Specimens in Bending Moment (굽힘 하중이 작용하는 비대칭노치시편의 완전소성해석)

  • Oh Chang-Kyun;Park Jin-Moo;Kim Yun-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.3
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    • pp.269-278
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    • 2006
  • This paper proposes slip line fields for bending of unequally notched specimens in plane strain that have a sharp crack in one side and a sharp V-notch in the other side. Depending on the back angle, two slip line fields are proposed, from which the limit moment and crack tip stress fields are obtained as a function of the back angle. Excellent agreement between slip line field solutions with those from detailed finite element limit analysis based on non-hardening plasticity provides confidence in the proposed slip line fields. One interesting point is that, for the unequally notched specimen, the difference between the crack tip triaxial stress for tension and that for bending increases significantly with increasing the back angle. This suggests that such a specimen could be potentially useful to investigate the crack tip constraint effect on fracture toughness of materials. In this respect, the possibility of designing a new toughness testing specimen with varying crack tip constraint is discussed.

Synthesis of Earthquake Ground Motion by Combining Stochastic Line Source Model with Elastic Wave Propagation Analysis Method in a Layered Half Space (추계학적 선진원 모델과 층상반무한체에서의 탄성파 전파 해석법에 의한 지진 지반운동 합성)

  • KIM, Jae Kwan;KWON, Ki Jun
    • Journal of Korean Society of Steel Construction
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    • v.8 no.3
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    • pp.97-105
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    • 1996
  • A Stochastic line source model is developed to simulate the seismic wave field generated during the rupture propagation process along a fault plane of which length is much larger than its width. The fault plane is assumed to consist of randomly distributed slip zones and barriers and each slip zone is modeled as a point source. By combining the newly developed source model with wave propagation analysis method in a layered 3-D visco-elastic half space, synthetic seismograms are obtained. The calculated accelerograms due to vertical dip slip and strike slip line sources are presented.

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Study of flat punch indentation to semi-infinite body with lpartially constrained free surface by moire method (구속표면을 가지는 반무한체에 대한 평저펀치의 압입의 연구)

  • ;Kim, Dong Won
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.3 no.4
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    • pp.164-172
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    • 1979
  • Experimental and numerical results concerning the flat punch indentation to semi-infinite body with partially constrained free surface are presented The distributions of slip line directions are predicted by Moire fringe analysis using Vinckier's method. A mumerical study is made of the same problem by finite element method and the results are compared with the experimental results. It is shown that the contour feature of possible slip line field is similar to that of well-known Prandtl indentation sloution.

Design of geocell reinforcement for supporting embankments on soft ground

  • Latha, G. Madhavi
    • Geomechanics and Engineering
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    • v.3 no.2
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    • pp.117-130
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    • 2011
  • The methods of design available for geocell-supported embankments are very few. Two of the earlier methods are considered in this paper and a third method is proposed and compared with them. In the first method called slip line method, plastic bearing failure of the soil was assumed and the additional resistance due to geocell layer is calculated using a non-symmetric slip line field in the soft foundation soil. In the second method based on slope stability analysis, general-purpose slope stability program was used to design the geocell mattress of required strength for embankment. In the third method proposed in this paper, geocell reinforcement is designed based on the plane strain finite element analysis of embankments. The geocell layer is modelled as an equivalent composite layer with modified strength and stiffness values. The strength and dimensions of geocell layer is estimated for the required bearing capacity or permissible deformations. These three design methods are compared through a design example. It is observed that the design method based on finite element simulations is most comprehensive because it addresses the issue of permissible deformations and also gives complete stress, deformation and strain behaviour of the embankment under given loading conditions.

Interfacial Crack-tip Constraints and J-integrals in Plastically Hardening Bimaterials under Full Yielding (완전소성하 변형경화 이종접합재의 계면균열선단 구속상태 및 J-적분)

  • Lee, Hyung-Yil;Kim, Yong-Bom
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.7
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    • pp.1159-1169
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    • 2003
  • This paper investigates the effects of T-stress and plastic hardening mismatch on the interfacial crack-tip stress field via finite element analyses. Plane strain elastic-plastic crack-tip fields are modeled with both MBL formulation and a full SEC specimen under pure bending. Modified Prandtl slip line fields illustrate the effects of T-stress on crack-tip constraint in homogeneous material. Compressive T-stress substantially reduces the interfacial crack-tip constraint, but increases the J-contribution by lower hardening material, J$\_$L/. For bimaterials with two elastic-plastic materials, increasing plastic hardening mismatch increases both crack-tip stress constraint in the lower hardening material and J$\_$L/. The fracture toughness for bimaterial joints would consequently be much lower than that of lower hardening homogeneous material. The implication of unbalanced J-integral in bimaterials is also discussed.

A robust indirect vector control for the rotor time constant variation of induction motors (유도전동기 회전자 시정수 변동에 강인한 간접 벡터제어)

  • 강현수;조순봉;현동석
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.45 no.3
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    • pp.365-373
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    • 1996
  • This paper presents the effects of rotor time constant variation and the on-line tuning algorithm of the rotor time constant. If the value of the rotor time constant is set incorrectly, the IFOC (Indirect Field Oriented Control)scheme exhibits deteriorated performance according to the wrong slip command. These variation effects of the rotor time constant are caused by the slip calculator where it is known that the rotor time constant play an important role in the aligned rotor flux. Using the two torque angles (stationary torque angle, rotating torque angle), the variation of the rotor time constant is identified, and the rotor time constant of the controller is tuned to the proper value of the machine. As the result, with the proposed algorithm, the dynamics of the deteriorated IFOC system, where the rotor time constant is varied, is improved. For the purpose of the validity of this proposed algorithm, the computer simulations and the experiments have been performed and the explanation of the results is presented. (author). refs., figs., tab.

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Anisotropy of Magnetic Susceptibility (AMS) of the Quaternary Faults, SE Korea: Application to the Determination of Fault Slip Sense and Paleo-stress Field (한반도 남동부 제4기 단층의 대자율이방성(AMS): 단층의 운동감각과 고응력장 해석)

  • Cho, Hyeongseong;Kim, Min-Cheol;Kim, Hyeonjeong;Son, Moon
    • The Journal of the Petrological Society of Korea
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    • v.23 no.2
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    • pp.75-103
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    • 2014
  • The Quaternary faults are extensively observed along major inherited fault zones (i.e. Yangsan Fault System, Ulsan Fault, Yeonil Tectonic Line, Ocheon Fault System) in SE Korea. Their geometry and kinematics provide a very useful piece of information about the Quaternary crustal deformation and stress field in and around Korean Peninsula. Using magnetic fabrics (AMS), we attempted to determine the slip senses of Jinti, Mohwa, Suseongji2, and Wangsan faults and then interpreted the fabric development process of fault gouge and the characteristics of stress field during the Quaternary. All the magnetic fabrics of the faults, except the Wangsan Fault, consistently indicate a dominant reverse-slip sense with weak strike-slip component. Most of the oblate fabrics are nearly parallel to the fault surface and the anisotropy degrees generally increase in proportion to the oblatenesses. These results suggest that the fabrics of the fault gouges resulted from a progressive deformation due to continuous simple shear during the last reactivation stage as reverse faulting. It is also interpreted that the pre-existing fabrics were overwhelmed and obliterated by the re-activated faulting. Paleostress field calculated from the fault slip data indicates an ENE-WNW compressive stress, which is in accord with those determined from previous fault tectonic analysis, focal mechanism solution, and hydraulic fracturing test in and around Korean Peninsula.