• Title/Summary/Keyword: loading condition

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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.

Relationships of Loading Rates and Bearing Capacities on Intermediate Soils (재하속도를 이용한 중간토의 지지력 평가)

  • 박중배
    • Geotechnical Engineering
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    • v.12 no.4
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    • pp.101-114
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    • 1996
  • In this study, the characteristics of bearing capacity and deformation of intermediate soils are investigated through centrifuge tests. The experimental parameters are footing width, initial stress condition of soils and relative loading rate defined relationship of loading rate and permeability of soils. It is examined that loading rate influences on the bearing capacities and deformations. Based on the test results, some problem of existing specification are introduced in the view of related loading rates and load intensities. Especially it is showed that load intensities magnitude rlre reversed in the same settlement ratio(s/B(%)), due to partial drained effect as well as loading rates in undrained con dition based on the excess pore pressure and deformations measured under loading.

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Prediction of Fracture Strains for DP980 Steel Sheets for a Wide Range of Loading Paths (다양한 하중경로에서의 DP980 강판의 파단변형률 예측에 관한 연구)

  • Park, N.;Huh, H.
    • Transactions of Materials Processing
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    • v.24 no.3
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    • pp.176-180
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    • 2015
  • The current study is concerned with the prediction of fracture strains for DP980 steel sheets over a wide range of loading paths. The use of DP980 steel is increasing significantly in automotive industries for enhanced safety and higher fuel efficiency. The material behavior of advanced high-strength steels (AHSSs) sheets sometimes show unpredictable and sudden fracture during sheet metal forming. A modified Lou-Huh ductile fracture criterion is utilized to predict the formability of AHSSs because the conventional forming limit diagram (FLD) constructed based on necking is unable to evaluate the formability of AHSSs sheets. Fracture loci were extracted from three dimensional fracture envelopes by assuming the plane-stress condition to evaluate equivalent plastic strains at the onset of fracture for a wide range of loading paths. Three different types of specimens -- pure shear, dog-bone and plane strain grooved -- were utilized for tensile testing to calibrate the fracture model of DP980 steel sheets. Fracture strains of each loading path were evaluated such that there shows little deviation between fracture strains predicted from the fracture model and the experimental measurements. From the comparison, it is clearly shown that the three dimensional fracture envelopes can accurately predict the onset of the fracture of DP980 steel sheets for complicated loading conditions from compressive loading to shear loading and to equibiaxial tensile loading.

A Study on Microbial Degradation for Removal of Toluene Vapour by Biofilter (Bio 필터를 이용한 Toluene 제거에서 미생물분해에 관한 연구)

  • 하상안;강신묵
    • Journal of environmental and Sanitary engineering
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    • v.14 no.1
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    • pp.24-30
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    • 1999
  • A biological filter for treatment of toluene among volatile organic compounds was studied. The investigation was conducted using specially built stainless steel columns packed with granular activated carbon and cold for removal of toluene. The G.A. and mold as filter material was also coated with Pseudomonas putida microorganisms.The biofilter unit was operated in the condition of moisture content vairation at gas loading rate of 12.5 l/min. Gaseous toluene taken from tedlar bag was analyzed by the use of G.C equipped with F.I.d detector. The removal efficiency of gaseous toluene was 95% at average inlet concentration of 950 ppm during bio-degradation operating condition. Effective removal efficiency was obtained with moisture content 27.5% at activated carbon and 32% at mold in this study. The effective operating condition were obtained with pH 6-8, temperature 28-42℃ for microbial degradation at gas loading rate of 12.5 l/min in packed material.

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An Experimental Study on Fatigue Fracture Behavior of Steel for Merchant Ships (선박용 강재의 피로파괴거동의 실험적 연구)

  • Moon-Sik,Han;Sang-Chul,Kim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.25 no.1
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    • pp.21-32
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    • 1988
  • An experimental study was carried out to identify the fatigue fracture behavior of steel for merchant ships. The bending and shear loads were applied simultaneously on the specimens to simulate of real load condition for a ship. The effects of the stress intensity factor under mode I with mode II loading condition on the initiation and the propagation of a crack were investigated, with particular emphasis on mode II. When the $K_{II}$ stress intensity factor in mode II was applied under mode I loading condition, the propagation behavior of a crack is to be affected mainly by the anisotropic characteristic of materials.

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Thermal Analysis of Transportation and Storage Cask of Spent Nuclear Fuel for Forced Gas Drying Condition

  • Lim, Suk-Nam;Chae, Gyung-Sun;Han, Jae-Hyun;Park, Jae-Seok;Lee, Dong-Gyu
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2017.05a
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    • pp.153-154
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    • 2017
  • The thermal analysis of transportation and storage cask for SNF was conducted during short term loading operations for forced gas drying condition. The fuel cladding temperature in 6 regions of SNF in the cask during the short term loading operations for forced gas drying condition is shown in the Fig. 3. The thermal analysis results of calculated maximum cladding temperature in each process demonstrate that operating scenario of TFD in detailed design maintain well below the temperature limits of $400^{\circ}C$.

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A Study on Lateral Loading the Field Test of Pile for Large Diameter Drilled Shaft Pile (대구경 현장타설말뚝에 대한 현장수평재하시험에 관한 연구)

  • Choi, Yong-Kyu;Lee, Min-Hee;Lee, Chung-Sook
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.2
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    • pp.33-39
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    • 2004
  • Most of pile foundations are a condition of fixed head on pile, but lateral loading test of pile have performed to free head on generally. This study performed field lateral loading test accompanying lateral displacement by depth of pile for two cases(fixed head and free head) and analyzed lateral behavior of large drilled shaft. Furthermore compared theoretical equation with result of lateral loading test.

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An Analysis on the Fluid-Loading Coefficients of Cylindrical Shell Structure With Arbitrary end Conditions (임의 경계조건을 가진 원통셸 구조의 유체영향계수 해석)

  • 전재진;정우진
    • Journal of KSNVE
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    • v.6 no.3
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    • pp.297-303
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    • 1996
  • The general approach using sine series expansions was represented to evaluate the radiation loading from a vibrating surface on a simply supported cylinder. In this paper, the fluid-loading coefficients (radiation impedance) for a submerged finite cylindrical shell with an arbitrary end condition are defined and evaluated. The vibrations of cylindrical shell are expressed by using cosine series expansions to analyze the radiation impedance for a finite cylindrical shell. It is possible to represent the displacements at both ends of cylindrical shell in comparison with sine series. The direct and cross modal components of fluid-loading coefficients are shown and the validity of cosine series expansions are verified from the results of numerical computations. This approach and results are directly applicable in the analysis of sound radiation from subemerged finite cylindrical shell with arbitrary end conditions.

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Fatigue Crack Propagation Behavior under Mixed Mode Loading (혼합모드 하중에서의 피로균열 전파거동)

  • 송삼홍;이정무;최병호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.481-484
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    • 2000
  • Practical structures are subject not only to tension but also to shear and torsional loading. Even under uniaxial loading, when the load is not perpendicular to the crack plane, mixed mode crack can occur. Hence, it is necessary to evaluate the fatigue behavior under mixed mode loading. In this study, the propagation behavior of the fatigue crack of the STS304 steels under mixed mode loading condition was investigated. The mode I and II stress intensity factors of CTS specimen were calculated using elastic finite element method with experimental results. The fatigue crack propagation under mixed mode was evaluated by the effective stress intensity factor proposed by Tanaka.

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Determination of Dynamic Tensile Behavior of Al5052-H32 using SHPB Technique (SHPB 테크닉을 이용한 Al5052-H32의 동적 인장 거동 규명)

  • 이억섭;김면수;백준호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.790-794
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    • 1997
  • Mechanical properties of the materials used for transportations and industrial machinery under high strain rate loading conditions such as seismic loading are required to provide appropriate safety assessment to those mechanical structures. The Split Hopkinson Pressure Bar(SHPB) technique with a special experimental behavior under high strain rate loading condition In this paper, dynamic deformation behaviors of A15052-H32 under high strain rate tensile loading are determined using the SHPB technique.

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