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Estimation of Settlement Caused by Lateral Displacement by Means of the Differences of Settlements from Consolidation Theory and Field Measurement (압밀이론에 의한 침하량과 현장계측 침하량의 차에 의한 측방유동 침하량 산정)

  • Kang, Min-Soo;Jeon, Sang-Ok;Eam, Sung-Hoon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.51 no.5
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    • pp.59-68
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    • 2009
  • In this study, it was developed that the software could be used to estimate consolidation settlement by curve fitting method according to Terzaghi's consolidation theory on the condition of gradual incremental loading, and the method of estimating settlement caused by lateral displacement was suggested, in which the settlement was calculated from the difference between the settlement calculated with the developed software using the early part of measured data and the settlement measured for the short duration from the beginning of embankment in the field. The verification of the suggested method of estimating settlement caused by lateral displacement showed good results.

FATIGUE DAMAGE PARAMETER OF SPOT WELDED JOINTS UNDER PROPORTIONAL LOADING

  • KANG H. T.
    • International Journal of Automotive Technology
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    • v.6 no.3
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    • pp.285-291
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    • 2005
  • In this paper, the author proposes a fatigue damage parameter of spot welded joints under proportional loading. The proposed fatigue damage parameter is developed based on von Mises' equivalent stress and local structural stress at the edge of spot weld nugget. The structural stress at the edges of the weld nugget in each sheet is calculated using the forces and moments that are determined by finite element analysis. A structural equivalent stress is then calculated by von Mises' equivalent stress equation. The structural equivalent stresses are correlated to experimental fatigue life of the spot welded joints. The proposed parameter is evaluated with fatigue test data of spot welds subjected to multi axial and tensile-shear loads. Sheppard's parameter and Rupp and co-workers' parameter are also evaluated with the same test data to compare with the author's parameter. This proposed parameter presents a better correlation with experimental fatigue data than those of Sheppard's and Rupp and co-workers' parameter. The proposed parameter should be very effective for durability calculations during the early design phase since coarsely meshed finite element models can be employed.

HAZ 연화부를 가진 TMCP형 고장력강판의 압축최종강도에 관한 연구 - 정사각형판

  • 백점기;고재용
    • Journal of Welding and Joining
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    • v.8 no.4
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    • pp.69-75
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    • 1990
  • In this paper, ultimate compressive strength of TMCP 50HT steel plates (yield stress .sigma.$_{o}$=36kg/mm$^{2}$) with HAZ softening is studied. Finite element method formulated by the author is applied to analyze the elasto-plastic large deflection behaviour of the plates. The influence of HAZ softening breadth, welding direction and slenderness ratio on the ultimate compressive strength is investigated. The results obtained are summarized as 1) With the increasing of the HAZ softening breadth, early plasticity on the plates is formed and then the ultimate compressive strength is decreased, in which about 8% of the ultimate strength for the plate with h/t=4(h: HAZ softening breadth, t: plate thickness) was reduced comparing with no HAZ softening. 2) The large decrease of the ultimate strength for the case that the welding direction is normal to the loading direction is occurred than the case that the welding direction is parallel to the loading direction. 3) The influence of HAZ softening on the ultimate compressive strength is serious for thick plates, while it may be negligible for thin plates.s.

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Evaluation of thermal striping damage for a tee-junction of LMR secondary piping”

  • Lee, Hyeong-Yeon;Kim, Jong-Bum;Bong Yoo;Yoon, Sam-Son
    • Proceedings of the Korean Nuclear Society Conference
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    • 1998.05b
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    • pp.837-843
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    • 1998
  • This paper presents the thermomechanical and fracture mechanics evaluation procedure of thermal striping damage on the secondary piping of LMFR using Green's function method and standard FEM. The thermohydraulic loading conditions used in the present analysis are simplified sinusoidal thermal loads and the random type data thermal load. The thermomechainical fatigue damage was evaluated according to ASME code subsectionNH. The analysis results of fatigue for the sinusoidal and random load cases show that fatigue failure would occur at a geometrically discontinuous location during 90,000 hours of operation The fracture mechanics analysis showed that the crack would be initiated at an early stage of the operation. The fatigue crack was evaluated to propagate up to 5 ㎜ along the thickness direction during the first 944 and 1083 hours of operation for the sinusoidal and the random loading cases, respectively.

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Microcrack Developement in Gabbro, Sandstone and Marble due to Fatigue Stress (압축피로하중에 의한 반려암, 사암 및 대리암에서의 미세균열 발달)

  • 장보안;김재동
    • Tunnel and Underground Space
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    • v.5 no.3
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    • pp.240-250
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    • 1995
  • Microcrack development in the macheon gabbro, the Sangju sandstone and the Jungsun marble due to fatigue stresses was investigated using differential strain analysis and microscopic observations from fluorescent-dyed thin sections. In the Macheon gabbro, various types of cracks, including gran boundary cracks, cleavage cracks, intragranular cracks adn intergranular cracks were developed. However, only grain boundary cracks were produced in the Sangju sandstone and the Jungsun marble due to fatigue stress. Many microcracks were produced due to fatigue stresses in the macheon gabbro. However, few microcracks were produced in the Sangju sandstone and the Jungsun marble. Fatigue stresses produced new microcracks in the Junngsun marble and the Macheon gabbro, but only pre-existing grain boundary cracks were lengthened in the Sangju snadstone. Most microcracks were produced within a few tens of numbers of cyclic loading, indicating that rocks under fatigue stresses will be damaged at the early stage of cyclic loading.

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ACN Estimation for Medium-class Aircraft (중형수송기 Aircraft Classification Number 예측)

  • Chung, Jin-Deog;Bae, Joong-Won;Lee, Hae-Chang
    • Journal of Aerospace System Engineering
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    • v.4 no.3
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    • pp.34-38
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    • 2010
  • ACN(Aircraft Classification Number) is allocated by marketing group during early stage of aircraft design phase and is a critical parameter to decide whether the designed aircraft can be landed or not in a certain airport. The loading on the main landing gear wheels, selection of main landing gear tire and estimation of ACNs for flexible and rigid pavements were done for the proposed medium-class aircraft. The estimated ACN values are compared with the similar class aircraft. And PCN(Pavement Classification Number) values of airport in Korea are surmmarized. Results showed that the currently proposed medium-class aircraft can land any airport in Korea.

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Prediction Method of Settlement Based on Field Monitoring Data for Soft Ground Under Preloading Improvement with Ramp Loading (점증 선행 하중으로 개량하는 연약지반의 계측기반 침하량 예측방법 개발)

  • Woo, Sang-Inn;Yune, Chan-Young;Baek, Seung-Kyung;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.24 no.10
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    • pp.83-91
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    • 2008
  • Previous settlement prediction methods based on settlement monitoring were developed under instantaneous loading condition and have restriction to be applied to soft ground under ramp loading condition. In this study, settlement prediction method under ramp loading was developed. New settlement prediction method under ramp loading considered influence factors of consolidation settlement such as thickness of clayed layer, quantity of surcharge load and preconsolidation pressure, etc. Geometrical correction method based on hyperbolic method (1991) and correction method based on probability theory were applied to increase accuracy of settlement prediction using field monitoring data after ramp loading. Large consolidation tests for ideally controlled one dimensional consolidation under ramp loading condition were performed and the settlement behavior was predicted based on the monitoring data. New prediction method yielded good result of entire settlement behavior by using data during an early stage of ramp load. Additionally, new prediction method offered better settlement prediction which had final settlement prediction in close proximity and low RMSE(Root Mean Square Error) than previous method such as hyperbolic method did.

Early Summer Dissolved Oxygen Characteristics in Restored Streams in Seoul (서울시 복원하천들의 초여름 용존 산소량 특성 분석)

  • Thoenen, Casey;Choi, Woonsup;Choi, Jinmu
    • Journal of the Korean Geographical Society
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    • v.48 no.3
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    • pp.336-347
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    • 2013
  • This paper presents an evaluation of stream restoration projects in Seoul with a focus on dissolved oxygen. Five test sites across four streams were measured for dissolved oxygen (DO) in late May to early June in 2012 and compared against a set of minimum and maximum thresholds. Only one test site, Hwarang-cheon, showed measurements below 6 mg/l DO. Towards the upper limit, the Hwarangcheon site was the only tested stream which was not at risk of DO supersaturation. The Danghyeon-cheon site had the highest probability of supersaturation, with DO saturation exceeding 130% expected 86.5% of the time. When measured every hour during daytime, DO levels showed diurnal variations, peaking in the afternoon. However, they showed inconsistent results along transects of the streams. Overall, the streams are rich in DO. To maintain the streams in good standing, nutrient loading should be addressed to prevent potential algal bloom induced hypoxic events down the line.

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Waterborne Noise Prediction of the Reinforced Cylindrical Shell Using the SEA Technique (SEA 기법을 이용한 보강 원통형 셸의 수중방사소음 해석)

  • 배수룡;전재진;이헌곤
    • Journal of KSNVE
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    • v.3 no.2
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    • pp.155-161
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    • 1993
  • The vibration generated by the machinery on board is transmitted to the hull and into the water. At the early design stage, the prediction of the hull vibration and the radiated noise level is very important to reduce their levels. In this study, SAE(Statistical Energy Analysis) technique is applied to predict structureborne noise level of the hull considering fluid loading. Rayleigh integral is applied to predict the radiated noise level. The results of comparision between the predictions and measurements for the reinforced cylindrical shell have shown good agreements.

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The Role of PET in Lung Cancer (폐암에서 PET의 역할)

  • Kim, Byung-Tae
    • The Korean Journal of Nuclear Medicine
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    • v.36 no.1
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    • pp.28-33
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    • 2002
  • Lung cancer has become a loading cause of cancer death in Korea. Positron emission tomography was introduced in clinical nuclear medicine in the early 1990s and many studios using this functional imaging technology were performed for evaluation of its clinical utility. I review the current role of positron emission tomography in the diagnosis, staging, and therapy monitoring of lung cancer.