• Title/Summary/Keyword: Section analysis method

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응력-침투 연계 해석에 의한 필 댐의 최적 설계

  • Park, Chun-Sik;Lee, Jun-Suk;Kim, Jong-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.862-870
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    • 2010
  • This thesis has been researched on optimized design method for the total cross section of embankment considering the fact that the size of embankment cross section is directly related with economic efficiency when dam designing. In general, embankment cross section of fill dam is either determined by cohesion and angle of internal friction, a strength parameter of embankment materials or by permeability of embankment. Therefore the size of embankment cross section depending on strength parameter of embankment materials was determined by using MIDAS-GTS program through stress-seepage coupled analysis at the time of fill dam design. As a result, determination of embankment cross section was more affected by the size of central core and permeability rather than by slope stability by shear strength and it was revealed that in case of embankment height being over 20m, stability against infiltration and slope action could be secured only when embankment slope is at least over 1:2.5. In addition, it was also revealed that in case of making the size of central core exceeding specification standard, total cross section of embankment could be reduced considerably and at the time of embankment design, adequate size and appropriateness of embankment cross section could be determined with referring the table suggested by this study.

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Estimating Ungauged River Section for Flood Stage Analysis (홍수위 해석을 위한 미측정 하천 단면 추정)

  • Shin, Sat Byeol;Kang, Moon Seong;Jun, Sang Min;Song, Jung Hun;Kim, Kyeung;Ryu, Jeong Hoon;Park, Jihoon;Lee, Do Gil;Lee, Kyeong-Do
    • Journal of The Korean Society of Agricultural Engineers
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    • v.58 no.5
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    • pp.11-18
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    • 2016
  • The objective of this study was to develop the simple method to estimate ungauged river section for flood stage analysis. Damage prediction should be prioritized using hydrological modeling to reduce flood risk. Mostly, the geographical data using hydrological modeling depends on national river cross-section survey. However because of the lack of measured data, it is difficult to apply to many local streams or small watersheds. For this reason, this study suggest the method to estimate unguaged river cross-section. Simple regression equations were derived and used to estimate river cross-section by analyzing the correlation between the river cross-sectional characteristics (width, height and area). The estimated cross-sections were used to simulate flood level by HEC-RAS (Hydrologic Engineering Center's River Analysis System). The applicability of this method was verified by comparing simulated flood level between measured and estimated cross-section. The water surface elevation of the flood stage analysis was 6.56-7.24 m, 5.33-5.95 m and 6.12-6.75 m for measured cross section, for estimated cross section and for estimated cross section based on DEM elevation, respectively. Further study should consider other factors for more accurate flood stage analysis. This study might be used one of the guidelines to estimate ungauged river section for flood stage analysis.

Analysis of ultrasonic scattering from nuclear fuel pins of liquid metal reactor (액체금속로 핵연료봉의 초음파 산란 해석)

  • 주영상
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1998.06e
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    • pp.247-250
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    • 1998
  • The scattering of plane ultrasonic waves by the nuclear fuel pin of liquid metal reactor in sodium is studied. According to the internal composition in the cladding tube, the fuel pin has three cross sections, i.e. helium gas plenum, sodium-filled section, and fuel insertion section. The scattering spectra for each section of the fuel pin are different. The circumnavigating ultrasonic waves of each section are analyzed by the resonance scattering method. The whispering gallery wave modes are generated in the sodium-filled plenum section and the fuel rod insertion section with a sodium-gap. The circumferential wave modes are propagated in the cladding tube of the helium gas plenum section. The annular gap between the cladding tube and metal uranium pellet rod affects the scattering spectra. The different propagation characteristics can be utilized for the nondestructive method of detecting the unbonded area and measuring the level of the sodium-filled section of the fuel pin.

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Impact Analysis on the Regional Economy Affected by Environmental Regulations (환경규제가 지역경제에 미치는 파급효과 분석)

  • 김호언
    • Journal of the Korean Regional Science Association
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    • v.15 no.3
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    • pp.1-13
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    • 1999
  • Since the 1990's, the most important environmental issue on the earth is characterized by "global worming problem". The United Nations Framework Convention on Climate Change (UNFCCC) plays an significant role to solve this problem on a worldwide scale. The main purpose of this paper is to analyse the impact of $CO_2$ reduction on the Daegu regional economy through 1995 regional input-output coefficients derived from the 1995 national input coefficients table by using non-survey method. The sectoral impacts on output, income, and employment were computed under the decline-unequalized assumption in final demand influenced by $CO_2$ reduction. This article has six main sections. Section 1 is an introduction to this paper. Section 2 explains briefly the derivation method of the regional technical coefficients. Section 3 describes the model building through input-output multipliers. In section 4 regional data on output, income, employment and final demand are computed to estimate the regional impacts. Section 5 deals with impact analysis on the Daegu economy. Section 6 contains a brief summary and concludintg remarks. The research findings of this study can be summarized as follows. In 1995, under the assumption of 10% decrease on an average in final demand sectors, the economy of the region studied decreased \3600 billion of output, ₩1114 billion of income, and 49919 man-years of employment. The percent ratios of each value to the total showed 9.4%, 9.7%, and 9.2%, respectively. The dominant sectors associated with impact analysis within the region are chemicals and chemical products, paper, printing and publishing, and textiles and leather, etc; nevertheless, the least dominant sector is non-metallic mineral products. products.

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Image Analysis of the Luster of Fabrics with Modified Cross-section Fibers

  • Shin Kyung In;Kim Seong Hun;Kim Jong Jun
    • Fibers and Polymers
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    • v.6 no.1
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    • pp.82-88
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    • 2005
  • We have investigated the luster of modified cross-sectional fiber fabrics as one of the essential quality estimates for clothing development. We have confirmed an objective evaluation method, and have determined the experimental luster char­acteristics of modified cross-section fibers. The cross-section of the fibers in a fabric affects the appearance of a textile. We used the image analysis method to investigate the luster to determine the critical factors influencing the appearance of modi­fied cross-section fiber fabrics. For similarly structured textiles in a component fabric, clear differences were observed in the fabric weave, density, percentage, and total area of blobs, which is image region. Color played a decisive role in the luster of the textiles, and luster was not significantly influenced by the modified cross-section fabric weave. In addition, the degree of luster did not increase in the order plain to twill to satin for modified cross-sectional fiber fabrics. All the split-type microfi­bers exhibited higher numerical luster values (percentage of pixels, and number and total area of blobs) than sea-island microfibers did. The degree of luster of the modified cross-sectional fiber fabrics was not high at specular reflection angles.

A Study of Heat Flow and Residual Stress Analysis in Pipe-plate Gas Metal Arc Brazing (파이프-평판 GMAB 접합부의 열유동 및 잔류음력 해석에 관한 연구)

  • 이태영;김재웅;이목영;정평석
    • Journal of Welding and Joining
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    • v.19 no.4
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    • pp.413-422
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    • 2001
  • In this study. two-dimensional heat flow and residual stress in arc brazing to join the pipe and plate structure were analyzed by using a commercialized FEM package. Advantages offered by arc brazing are that strong joints can be produced with lower heat input than that of previous gas metal arc welding and narrower heat affected zone can usually be obtained than that in the case of torch brazing. To investigate the effects of process variables and minimize the thermal effects on the structure, this study presents a method for analyzing the heat flow and residual stress in arc brazing process according to variables such as traveling speed, torch angle and position. The simulation results were compared with the experimental ones to verify the numerical analysis method. The experiments include the measurement of HAZ size from the section of joints and residual stresses by using strain gages named 'section method'. A comparatively good agreement between the results of numerical analysis and experimental ones could be obtained in both of the temperature distribution and residual stress of the brazed structure. Using the proposed numerical analysis method, the process parameters were evaluated to get proper arc brazing conditions.

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Torsion of circular open cross-section with corrugated inner and outer surface

  • Pala, Yasar;Pala, Abdullah
    • Structural Engineering and Mechanics
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    • v.73 no.1
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    • pp.75-82
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    • 2020
  • In this study, the problem of torsion of bars with open cross section surrounded by corrugated boundaries is analyzed. An approximate analytical solution is given using perturbation technique. First, the stress analysis for circular open cross-section for arbitrary opening angle is formulated and the problem is analytically solved. Second, the open cross-section with corrugated cross section is analyzed using perturbation method. First order contributions to the stresses and the torques have been added. The results have been exemplified and compared by considering special examples.

Three-dimensional Vibration Analysis of Circular Rings with an Elliptical or Circular Cross-section (타원형 또는 원형 단면을 가진 원형 링의 3차원적 진동해석)

  • Shim, Hyun-Ju;Woo, Ha-Young;Kang, Jae-Hoon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.10 s.115
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    • pp.1024-1035
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    • 2006
  • A three-dimensional (3-D) method of analysis is presented for determining the free vibration frequencies and mode shapes of thick, complete (circumferentially closed), circular rings with an elliptical or circular cross-section. Displacement components $u_r,\;u_\theta\;and\;u_z$ in the radial, circumferential, and axial directions, respectively, are taken to be periodic in ${\theta}$ and in time, and algebraic polynomials in the r and z directions. Potential (strain) and kinetic energies of the circular rings are formulated, and upper bound values of the frequencies are obtained by minimizing the frequencies. As the degree of the polynomials is increased, frequencies converge to the exact values. Convergence to four-digit exactitude is demonstrated for the first five frequencies of the rings. Novel numerical results are presented for the circular rings having an elliptical cross-section based upon 3-D theory. Comparisons are also made between the frequencies from the present 3-D Ritz method and ones obtained from thin and thick ring theories, experiments, and another 3-D method.

Longitudinal anti-cracking analysis for post-tensioned voided slab bridges

  • Zhou, Zhen;Meng, Shao-Ping;Liu, Zhao
    • Structural Engineering and Mechanics
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    • v.43 no.4
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    • pp.459-473
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    • 2012
  • Post-tensioned concrete voided slab girders are widely used in highway bridge constructions. To obtain greater section hollow rate and reduce the self-weight, the plate thickness of slab girders are designed to be small with the adoption of flat anchorage system. Since large prestress is applied to the anchor end section, it was found that longitudinal shear cracks are easy to occur along the voided slab girder. The reason is the existence of great shearing effect at the junction area between web and bottom (top) plate in the anchor end section. This paper focuses on the longitudinal anti-cracking problem at the anchor end of post-tensioned concrete voided slab girders. Two possible models for longitudinal anticracking analysis are proposed. Differential element analysis method is adopted to derive the solving formula of the critical cracking state, and then the practical analysis method for longitudinal anti-cracking is established. The influence of some factors on the longitudinal anti-cracking ability is studied. Results show that the section dimensions (thickness of bottom, web and top plate) and prestress eccentricity on web plate are the main factors that influence the anti-cracking ability. Moreover, the proposed method is applied into three engineering examples to make longitudinal anti-cracking verification for the girders. According to the verification results, the design improvements for these girders are determined.

Reliability Evaluation of a Distribution System with wind Turbine Generators Based on the Switch-section Partitioning Method

  • Wu, Hongbin;Guo, Jinjin;Ding, Ming
    • Journal of Electrical Engineering and Technology
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    • v.11 no.3
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    • pp.575-584
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    • 2016
  • Considering the randomness and uncertainty of wind power, a reliability model of WTGs is established based on the combination of the Weibull distribution and the Markov chain. To analyze the failure mode quickly, we use the switch-section partitioning method. After defining the first-level load zone node, we can obtain the supply power sets of the first-level load zone nodes with each WTG. Based on the supply sets, we propose the dynamic division strategy of island operation. By adopting the fault analysis method with the attributes defined in the switch-section, we evaluate the reliability of the distribution network with WTGs using a sequential Monte Carlo simulation method. Finally, using the IEEE RBTS Bus6 test system, we demonstrate the efficacy of the proposed model and method by comparing different schemes to access the WTGs.