• Title, Summary, Keyword: block force

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Analysis of the Frictional Behavior of Rubber Block (고무 블록의 마찰 거동 해석)

  • Kim, Doo-Man;Yoo, Hyun-Seung
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.14 no.3
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    • pp.16-22
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    • 2006
  • The friction and wear of tire determined by frictional behavior of tire tread that translate driving force, cornering force and braking force between automobile and road as a result of frictional behavior of each tread block. The tire tread block is representative case of rubber block doing frictional behavior. In this paper, frictional behavior of rubber block under compressive force and shear force was analytically obtained by using slip starting position parameter instead of friction coefficient which is uncertain to express exact value between rubber and other surfaces yet. And local coefficients of friction were calculated as a function of compressive force, shear force, shear modulus of rubber, shape factor and slip starting position.

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Evaluation of Force Components and Newmark Sliding Block Analysis of Quay Walls during Earthquake (지진동을 받는 중력식 안벽에 작용하는 하중산정 및 Newmark 변위해석)

  • 김성렬;하익수;권오순;김명모
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.93-100
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    • 2002
  • In this paper, new simple model is developed to evaluate the variation of the magnitude and the phase contrast of force components with the development of excess pore pressure in backfill soil. Also, Newmark sliding block analysis is performed inputting the calculated total force from new model. The applicability of new simple model and Newmark sliding block model is verified from the analyses of 1g shaking table test results.

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Effects of the Block Distance of Collecting Plate and Particle Size on the particle Deposition Efficiency in the Two-Stage Electrostatic Precipitator (2단식 전기집진기의 집진판 블록간격 및 입자크기가 입자의 부착효율에 미치는 영향)

  • 박청연
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.2
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    • pp.165-178
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    • 2000
  • In this study the effects of block distance have been investigated on the particle deposition efficiency in the collecting cell of two-stage electrostatic precipitator by numerical analysis. Particle trajectories have been changed by the electrostatic and inertial force of particle with the inlet velocity electrostatic number and particle diameter. The total deposition efficiency has a minimum value by the interaction between the effect of particle inertial force and electrostatic force in the collecting cell. The increase of block distance makes the total deposition efficiency decrease under the range of the particle size which has the minimum deposition efficiency. However beyond the range of particle size which has minimum deposition efficiency total deposition efficiency has no trend with the variation of block distance.

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Passive Force Acting on the Kicker Block Used to Support a Raker in Soft and Weathered Soil (연약지반과 풍화토지반에서 경사고임대 지지블록의 수동토압 산정)

  • Kim, Tae Hyung;Park, Lee Keun;Kim, Tae O;Jin, Hyun Sik
    • Journal of The Korean Society of Civil Engineers
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    • v.37 no.5
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    • pp.801-813
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    • 2017
  • Passive force acting on the kicker block used to support a raker is different dependent on soil's type. The passive force incorporating a factor of safety is considered for design of the retaining wall. However, an actual passive force developing on the kicker block is overestimated and it may lead to an unsafe design. In this study, the actual passive forces acting on the kicker block in soil ground are evaluated using 3-D Finite Element Program, PLAXIS. Soft and weathered soils are selected as a soil ground. The relation curves between horizontal displacement and actual passive force of the kicker block for each soil ground are obtained through numerical analyses. From the curves, the actual passive forces are determined as a yielding point, which are about 55.5% and 66% of Rankine's passive forces in soft and weathered soils, respectively.

Calculation of the Dynamic Contact Force between a Shipbuilding Block and Wire Ropes of a Goliath Crane for the Optimal Lug Arrangement (최적 러그 배치를 위한 골리앗 크레인의 와이어 로프와 선체 블록간의 동적 접촉력 계산)

  • Ku, Nam-Kug;Roh, Myung-Il;Cha, Ju-Hwan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.5
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    • pp.375-380
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    • 2012
  • In this study, dynamic load and dynamic contact force between a building block and wire ropes of a goliath crane are calculated during lifting or turn-over of a building block for the design of an optimal lug arrangement system. In addition, a multibody dynamics kernel for implementing the system were developed. In the multibody dynamics kernel, the equations of motion are constructed using recursive formulation. To evaluate the applicability of the developed kernels, the interferences and dynamic contact force between the building block and wire ropes were calculated and then the hull structural analysis for the block was performed using the calculation result.

The Dynamic Characteristics Analysis Between Pantograph and Catenary System Using Block Pulse Function (블럭펄스함수를 이용한 판토그래프와 가선시스템사이의 동특성 해석)

  • Shin, Seung-Kwon;Song, Yong-Soo;Eum, Ju-Hwan;Eum, Ki-Young
    • Proceedings of the KIEE Conference
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    • pp.748-750
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    • 2004
  • The pantograph should supply the electrification equipments of a train with the current from the overhead catenary system over a broad range of speeds. For a high-speed electrical train, the dynamic interaction between the pantograph and the overhead catenary system causes the variation of the contact force. As the operational speed increases, the variation of the contact force increases. The contact force variation can cause contact losses, arcing and sparking. If the spark happens between the pantograph and the overhead catenary system, the EMI(electro magnetic interface) and noises may occur. After all, the quality of current collection is deteriorated. This paper deals with the dynamic characteristics analysis between pantograph and catenary system using block pulse function.

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Friction characteristics between the cylinder block and the valve plate in axial piston pump (액셜 피스톤 펌프에서 실린더 블록과 밸브 플레이트 사이의 마찰 특성)

  • 김종기;정재연
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.249-255
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    • 1998
  • To increase the efficiency of the hydraulic axial piston pumps, we have to know the various characteristics in the sliding parts of them. Especially, friction characteristics between the cylinder block and the valve plate in the hydraulic axial piston pumps plays an important role to high power density. In this paper, we tried to clarify friction characteristics between the cylinder block and the spherical valve plate in bent-axis-type axial piston pump by using of modeling experiment. The main results of this study are these; (1) Friction torque between the cylinder block and the spherical valve plate has a proportional relation to weight or rotational speed, and is strongly affected by temperature. (2) Friction torque strongly depends on force balance ratio. (3) In this experiment, lubrication condition between the cylinder block and the spherical valve plate is under hydrodynamic lubrication.

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Friction Characteristics between the Cylinder Block and the Spherical Valve Plate in Hydraulic Axial Piston Pump (유압 액셜 피스톤 펌프에서 실린더 블록과 구면 밸브 플레이트 사이의 마찰 특성)

  • 김종기;오석형;정재연
    • Tribology and Lubricants
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    • v.14 no.4
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    • pp.23-28
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    • 1998
  • To increase the efficiency of the hydraulic axial piston pumps, it is need to know the various characteristics in the sliding contact parts of them. Especially, friction characteristics between the cylinder block and the valve plate in the hydraulic axial piston pumps plays an important role to high power density. In this paper, we tried to clarify friction characteristics between the cylinder block and the spherical valve plate in bent-axis-type axial piston pump in experimentally. Results are arranged as follow; (1) friction torque between the cylinder block and the spherical valve plate has a proportional relation to weight or rotational speed, and is strongly affected by temperature. (2) Friction torque strongly depends on force balance ratio in valve plate. (3) In this experiment, lubrication condition between the cylinder block and the spherical valve plate is under hydrodynamic lubrication.

Design equation to evaluate bursting forces at the end zone of post-tensioned members

  • Kim, Joung Rae;Kwak, Hyo-Gyoung;Kim, Byung-Suk
    • Computers and Concrete
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    • v.24 no.5
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    • pp.423-436
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    • 2019
  • Design equations to evaluate the bursting force in a post-tensioned anchorage zone have been introduced in many design codes, and one equation in AASHTO LRFD is widely used. However, this equation may not determine the bursting force exactly because it was designed on the basis of two-dimensional numerical analyses without considering various design parameters such as the duct hole and shape of the bearing plate. To improve the design equation, modification of the AASHTO LRFD design equation was considered. The behavior of the anchorage zone was investigated using three-dimensional linear elastic finite element analysis with design parameters such as bearing plate size and diameter of sheath hole. Upon the suggestion of a modified design equation for evaluating the bursting force in an anchorage block with a rectangular anchorage plate (Kim and Kwak 2018), additional influences of design parameters that could affect the evaluation of bursting force were investigated. An improved equation was introduced for determining the bursting force in an anchorage block with a circular anchorage plate, using the same procedure introduced in the design equation for an anchorage block with a rectangular anchorage plate. The validity of the introduced design equation was confirmed by comparison with AASHTO LRFD.

Limit analysis of rectangular cavity subjected to seepage forces based on Hoek-Brown failure criterion

  • Yang, X.L.;Qin, C.B.
    • Geomechanics and Engineering
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    • v.6 no.5
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    • pp.503-515
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    • 2014
  • On the basis of Hoek-Brown failure criterion, a numerical solution for the shape of collapsing block in the rectangular cavity subjected to seepage forces is obtained by upper bound theorem of limit analysis. The seepage forces obtained from the gradient of excess pore pressure distribution are taken as external loadings in the limit analysis, and the pore pressure is easily calculated with pore pressure coefficient. Thus the seepage force is incorporated into the upper bound analysis as a work rate of external force. The upper solution of the shape of collapsing block is derived by virtue of variational calculation. In order to verify the validity of the method proposed in the paper, the result when the pore pressure coefficient equals zero, and only hydrostatic pressure is taken into consideration, is compared with that of previous work. The results show good effectiveness in calculating the collapsing block shape subjected to seepage forces. The influence of parameters on the failure mechanisms is investigated.