• 제목/요약/키워드: Eccentric Hole

검색결과 20건 처리시간 0.023초

독립좌표연성법을 이용한 편심 된 원형 구멍을 갖는 원판의 자유진동해석 (Free Vibration Analysis of a Circular Plate with an Eccentric Circular Hole by the Independent Coordinate Coupling Method)

  • 허석;곽문규
    • 한국소음진동공학회논문집
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    • 제18권6호
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    • pp.681-689
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    • 2008
  • This paper is concerned with the free vibration analysis of a circular plate with an eccentric circular hole by the Independent coordinate coupling method(ICCM). It was proved in the previous study that the ICCM can accurately predict the natural frequencies and mode shapes of the annular plates and can also be used for the free vibration analysis of the simply-supported circular plate with an eccentric circular hole. In this study, the clamped and free boundary conditions were considered for the circular plate. The numerical results show that the ICCM can be used effectively for the free vibration problem of circular plate with an eccentric hole compared to the finite element method.

신경망 기법을 이용한 1축 잔류응력장에서 구멍뚫기법의 구멍편심 오차 보정 (Compensation of the Error due to Hole Eccentricity of Hole-drilling Method in Uniaxile Residual Stress Field Using Neural Network)

  • 김철;양원호;조명래
    • 대한기계학회논문집A
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    • 제26권12호
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    • pp.2475-2482
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    • 2002
  • The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is compensated using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could compensated the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for compensation of the error due to hole eccentricity in hole-drilling method.

신경망 기법을 이용한 구멍뚫기법에서의 구멍 편심오차 보정 (Correction of Error due to Hole Eccentricity in Hole-drilling Method Using Neural Network)

  • 김철;양원호;조명래;허성필
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집A
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    • pp.412-418
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    • 2001
  • The measurement of residual stresses by the hole-drilling method has been commonly used to evaluate residual stresses in structural members. In this method, eccentricity can usually occur between the hole center and rosette gage center. In this study, the error due to the hole eccentricity is corrected using the neural network. The neural network has trained training examples of normalized eccentricity, eccentric direction and direction of maximum stress at eccentric case using backpropagation learning process. The trained neural network could corrected the error of measured residual stress in experiments with hole eccentricity. The proposed neural network is very useful for correction of the error due to hole eccentricity in hole-drilling method.

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Tidal Disruption Flares from Stars on Bound Orbits

  • Hayasaki, Kimitake;Stone, Nicholas;Loeb, Abraham
    • 천문학회보
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    • 제38권2호
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    • pp.60.1-60.1
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    • 2013
  • We study tidal disruption and subsequent mass fallback process for stars approaching supermassive black holes on bound orbits, by performing three dimensional Smoothed Particle Hydrodynamics simulations with a pseudo-Newtonian potential. We find that the mass fallback rate decays with the expected -5/3 power of time for parabolic orbits, albeit with a slight deviation due to the self-gravity of the stellar debris. For eccentric orbits, however, there is a critical value of the orbital eccentricity, significantly below which all of the stellar debris is bound to the supermassive black hole. All the mass therefore falls back to the supermassive black hole in a much shorter time than in the standard, parabolic case. The resultant mass fallback rate considerably exceeds the Eddington accretion rate and substantially differs from the -5/3 power of time. We also show that general relativistic precession is crucial for accretion disk formation via circularization of stellar debris from stars on moderately eccentric orbits.

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A Study of Hot Metal Extru-Bending Process

  • 진인태
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2002년도 제5회 압출 및 인발가공 심포지엄
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    • pp.63-70
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    • 2002
  • The purpose of the present study is to propose a new way of manufacturing curved metal tubes with arbitrary sections and way of eliminating the conventional bending defects such as thinning and thickening, in the wall of tube, distortion of the section, and wrinkling and folding on the surface by the extrusion bending process that can extrude and weld together one or more billets inside dies cavity, and can bend them during extrusion due to the gradient of extrusion velocities controlled by the eccentricity of the cavity sections between the entrance and the exit of the eccentric conical extrusion bending dies and conical plug, or by the relative size of the holes of multi-hole container, or by the relative moving velocity of multi-punches.

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FREE VIBRATION ANALYSIS OF CIRCULAR PLATE WITH ECCENTRIC HOLE SUBMERGED IN FLUID

  • Jhung, Myung-Jo;Choi, Young-Hwan;Ryu, Yong-Ho
    • Nuclear Engineering and Technology
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    • 제41권3호
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    • pp.355-364
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    • 2009
  • Circular plates with holes are extensively used in mechanical components. The existence of a hole in a circular plate results in a significant change in the natural frequencies and mode shapes of the structure. Especially if the hole is located eccentrically, the vibration behavior of these structures is expected to deviate significantly from that of a plate with a concentric hole. In addition, if the plate is in contact with or submerged in fluid, the situation is more complex. Therefore, in this study, an analytical method to determine the modal characteristics of a plate submerged in fluid is developed based on the finite Fourier-Bessel series expansion and Rayleigh-Ritz method and is verified by the finite element analysis using a commercial program. Also, the relationship between parameter variations and vibration modes is investigated. These results can be used as guidance for the modal analysis and damage detection of a circular plate with a hole.

폐톱밥 혼입 RC 유공보의 구조거동에 관한 실험적 연구 (Structural Behavior of Holed RC Beam mixed with Sawdust)

  • 손기상;이재형
    • 한국안전학회지
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    • 제21권1호
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    • pp.96-104
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    • 2006
  • This study is to find out how the sawdust-mixed RC beam with holes acts compared to two case of normal one with sawdust without hole, without sawdust. variables are ED3H1, ED3H2, ED3H1UB, ED3H2L, ED5H1, ED5H1UB, ED5H2, ED5H2L, Normal with sawdust PLA without sawdust. All sand, aggregate, cement are in accordance with KS. mixing design is also in accordance with KS and done at D remicon company in order to decrease any error in mixing manually. ED3H1 showed 7tone of maximum load capacity having only minor tensile deformation around hole, compared to the center of the beam. ED5H2L showed almost same shape of tensile strain between hole area and center of two beam length, while having 9.5 tone load capacity, incase of two holes being in the longitudinal axis. But ED5H2 in case of two holes being in same forcing direction showed 8.4tone of load capacity while having minor tensile chape around hole and normal tensile shape in the center of beam length. Two diameter 3cm hole in longitudinal axis give more effective behavior than the other case, practically. Capacity decrease between 5cm and 3cm in eccentric position form the longitudinal axis is less than percents. There is minor capacity difference between hole diameter 3cm hole, but 13tone difference of load capacity between hole diameter 5cm.

유공위치 변경에 따른 RC기둥의 내력변화에 관한 실험적 연구 (Stress Change Varying with Hole Place of RC Column)

  • 손기상
    • 한국안전학회지
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    • 제21권2호
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    • pp.70-79
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    • 2006
  • many plumbing system are needed in the ceiling of the building as it becomes advanced more and more. This leads to make effective space between ceiling level and slab less. Also, piping system is not suitably arranged and operated if it is bent around the columns which they are a lot. But this system can be more effective if it passes through the columns directly. Most people think that those columns should not be damaged with such as holes. But actually this is existed in a hotel building in switzerland. This study is to fing out how much capacity the columns become damaged and low using model size of $20cm{\times}30cm$ rectangular section, and 160cm long, in the structural test. it's compressive strength is focused on $240kg/cm^{2}$ design strength, commonly used in korea. Compressive test for them was done at Hanyang University using UTM one thousand tone(1000t) capacity. Variable numbers for the study are one hole of dia 3cm with distance 20cm or 40cm, two holes of dia 3cm with 20cm and 40cm distance, one hole of dia 5cm with distance 20cm and 40cm, two holes of dia 5cm with 20cm and 40cm distance, me eccentric hole with 20cm and 40cm distance, Normal(without hole). two test specimens of each variable are made for the test. ED5H20 capacity was 16.7% decreased, compared to normal one. While ED5H40 distant 40cm from the end of column top showed 19.5% capacity decrease, compared to normal one. Strain of ED5H20 diameter 5cm, in distance of 20cm form the top of the column was less 5% than the one of diameter 3cm. Finally, conclusions are that in case of hole diameter 3cm, located at 20cm from the end of the column top, capacity was decreased down to 3, percent only compared to the same diameter hole with 20cm distant from the end of it.

소형 인장 시험편 내의 크랙 전파에 대한 구조 안전해석 (Structural Safety Analysis on Crack Propagation in Compact Tension Specimen)

  • 조재웅
    • 한국융합학회논문지
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    • 제5권1호
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    • pp.23-27
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    • 2014
  • 본 연구에서는 소형 인장 시험편에 편심된 집중하중을 가하였을 때, 크랙 주변에서의 구멍의 존재유무, 개수 및 위치에 따른 전파 거동에 대하여 규명하였다. 시뮬레이션 해석을 통하여 시험편에서 발생하는 Strain energy와 변형량, 응력에 대해 알 수 있었다. 그리고 이들 Strain energy와 변형량을 바탕으로 응력확대계수를 구하였으며, 본 연구결과를 이용하면 구조물 내에 결함이나 구멍 등이 있을 때 그 파괴 가능성을 검증할 수 있다고 사료된다.