• 제목/요약/키워드: Design formula

검색결과 1,321건 처리시간 0.029초

위험도를 고려한 최소비용 도시우수관망 설계의 최적화 모형개발 (I): 모형의 개발과 시험유역의 적용 (Development of Optimal Design Simulation Model for Least Cost Urban Sewer System Considering Risk (I))

  • 장석환;박상우
    • 한국수자원학회논문집
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    • 제38권12호
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    • pp.1021-1028
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    • 2005
  • 본 연구는 도시 우수관망 설계 시 주어진 설계유랑을 효율적이고 경제적인 단면 구성과 관망에 따른 우수배제능력을 극대화시키기 위해 최적화된 설계를 통하여 경제적인 우수시스템을 설계할 수 있는 모형의 개발이 이루어져야 할 필요성이 있다. 이에 본 연구에서는 최적화 기법으로 동적계획법(Dynamic Programming : DP)의 특수한 방법인 이산미분형 동적계획법(Discrete Differential Dynamic Programming : DDDP)를 이용해 최적화된 설계조건을 구할 수 있도록 하였다. 이산미분형 동적계획법의 기법은 설계유랑과 맨홀의 위치가 결정되면 그에 따른 최적 우수시스템이 될 수 있는 관의 용량, 경사, 수위, 수심, 위험도, 회수비용 등을 결정할 수 있는 방법으로 이는 공사비용에 따른 최소비용을 목적함수로 위험도 분석을 통하여 최적화된 조건을 찾는 방법으로 모형개발을 하였다.

한국에 있어서 강우강도의 효과에 관한 연구 (The Study to Derive Empirical Formula of Rainfall Intencity in Korea)

  • 박성우
    • 한국농공학회지
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    • 제11권2호
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    • pp.1644-1650
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    • 1969
  • In the design of general hydrological structures, it is well know that the design flood is of importance in the design of those structures. As the design flood is estimated using the design storm, the design storm is defined by the rainfall intensity itself. Though I had studied and reported many times the reports about the rainfall-intensity in my country, poorly I did not study the long-period variation of the intensity through each section in my country before. But now, in the basin area of the Han river and the Keum river, the self-recorded rainfall charts of the single storms, which are mostly above rainfall amount of 30mm and data of about 4500 with the 150 stationyear, were analyzed, And then, the intensity formula of the hourly unit is estimated using the period from 10 minutes to 5 days. The method to analyze and estimate them, and the final results will be summarized as mentioned below: (i) At first I intended to select out the homogeneous watersheds of three, one in the Han river and two in the Keum river. But I would select the northern and the sourthern river basins, and westward from Koan station, in the basins of the Han river. Also I would select the upstream area, and the downstream area including the watershed of Chungioo, Kongjoo, Chupungryung, and the Mt. Sock, in the basins of the Keum river. Finally, I could find that there couldn't in the Keum river basin. So, I decided out and analyze only river basins of the Han river with limitation mentioned above. (ii) The statistical method to select out the homogenous watersheds is the test of homogeneous variance, and it is estimated from the following equation: $$X_{k1}^2=[{\Sigma}(n_i-1)log\bar{S^2}-\Sigma(n_i-1)log\bar{S^2}]{\times}loge$$ (iii) Actually, each homogeneous watershed has individually its own intensity formula, But I would express them as the actual amount, because the equation of intensity variance is experiential and theoretical equation of the variance. Therefore the caluating equation is actually more convenient in the actual uses. (iv) This report is one of the series for me to give the basis to the actual designs. The cost for this study is provided by the Ministry of Construction. And the designs of the hydrological structures in the watersheds with limitation mentioned above may be concerned with and based upon this report.

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국내 항타강관말뚝 설계법의 목표 신뢰도지수 (Target Reliability Indices of Static Design Methods for Driven Steel Pipe Piles in Korea)

  • 곽기석;허정원;김경준;박재현;이주형
    • 대한토목학회논문집
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    • 제28권1C호
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    • pp.19-29
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    • 2008
  • 국내 기초구조물에 대한 하중저항계수설계법 개발의 일환으로 항타강관말뚝에 대한 신뢰성 수준을 평가하고 목표 신뢰도지수를 결정하였다. 국내 정재하시험 및 지반조사 자료를 수집하여 말뚝의 대표 측정 극한지지력을 결정하였고, 정역학적 지지력공식과 Meyerhof 경험식을 이용하여 설계 극한지지력을 산정하였다. 이들 자료의 비교 분석을 통해 저항편향계수를 산정하였다. 저항편향계수의 통계 특성을 이용하여 일차신뢰도법 및 몬테카를로 시뮬레이션에 의한 신뢰성 분석을 실시하였다. 정역학적 지지력공식은 자료의 변동성이 낮았고 Meyerhof 경험식은 내재적 보수성이 크게 나타났다. 안전율 3.0~5.0에 대한 신뢰도지수 분석 결과 정역학적 지지력공식은 1.50~2.89, Meyerhof 경험식은 1.61~2.72로 평가되었다. 신뢰성 분석 결과를 바탕으로 목표 신뢰도지수는 무리말뚝으로 시공되는 경우 2.0, 2.33을, 무리말뚝으로 시공되지 않는 경우 2.5의 값을 결정하였다.

PACE 경주용 차량의 조종안정성 개선에 대한 연구 (Study on Vehicle Stability Enhancement for the PACE Formula Vehicle)

  • 김관주;김현준;이준헌
    • 한국자동차공학회논문집
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    • 제19권1호
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    • pp.25-31
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    • 2011
  • The purpose of the study is to enhance the vehicle handling stability of the PACE formula vehicle. Required data for the dynamic analysis of the vehicle are as follows: Mass, moment of inertia, and tire's dynamic properties. Mass and moment of inertia data were calculated using Siemens NX 5.0 which results were verified with VIMF measurements of GMDAT. Dynamic data for the tire were supplied by Kumho Tire. Aerodynamic forces play an important role in the formula vehicle which forces were calculated by using Fluent. Full vehicle dynamic analysis using Carsim software has been carried out to find out the improvement of the vehicle stability by changing the shapes of the rear wing.

H형(形) 강(鋼) 보의 횡좌굴(橫挫屈)에 관(關)한 연구(硏究) (A Study On Lateral Buckling Of H-Section Steel Beams)

  • 김석중
    • 산업기술연구
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    • 제4권
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    • pp.29-35
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    • 1984
  • Buckling is a significant behavior to be considered whenever we design steel structures. In the case of H-shape beams, the lateral buckling occured by bending moment must be considered. Because of the lateral buckling of H-shape beams, the bending strength of the beams are determined by the lateral buckling stress instead of the allowable bending stress. Lateral buckling stress equation, consisting of two terms, i. e. ${\sigma}_{cr}({\nu},{\omega})={\sqrt{[{\sigma}_{cr}({\nu})]^2+[{\sigma}_{cr}({\omega})]^2}}$ has been using, but for the practical purpose of use the following equations are using two, i. e. ${\sigma}_{cr}({\nu})={\frac{0.65E}{{\ell}_h/A_f}}$, ${\sigma}_{cr}({\omega})={\frac{{\pi}^2E}{({\ell}_b/i_b)^2}}$. When we use the above equations, the results are different according to the shape of beam section, and they a re rather complex. In this study lateral buckling stress equation is derived, and the proposed formula$({\sigma}_{cr}(t))$ is compared with above mentioned two basic and practical equations. To verify the proposed formula experimentaly, 16H-shape beams which have different slender ratios arc tested by applying pure bending momet. Through the experiments the buckling behavior of H-shape beams is clarified, and the results shows that the proposed formula$({\sigma}_{cr}(t))$ is accurate enough for practical purpose.

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Mechanical parameters detection in stepped shafts using the FEM based IET

  • Song, Wenlei;Xiang, Jiawei;Zhong, Yongteng
    • Smart Structures and Systems
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    • 제20권4호
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    • pp.473-481
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    • 2017
  • This study suggests a simple, convenient and non-destructive method for investigation of the Young's modulus detection in stepped shafts which only utilizes the first-order resonant frequency in flexural mode and dimensions of structures. The method is based on the impulse excitation technique (IET) to pick up the fundamental resonant frequencies. The standard Young's modulus detection formulas for rectangular and circular cross-sections are well investigated in literatures. However, the Young's modulus of stepped shafts can not be directly detected using the formula for a beam with rectangular or circular cross-section. A response surface method (RSM) is introduced to design numerical simulation experiments to build up experimental formula to detect Young's modulus of stepped shafts. The numerical simulation performed by finite element method (FEM) to obtain enough simulation data for RSM analysis. After analysis and calculation, the relationship of flexural resonant frequencies, dimensions of stepped shafts and Young's modulus is obtained. Numerical simulations and experimental investigations show that the IET method can be used to investigate Young's modulus in stepped shafts, and the FEM simulation and RSM based IET formula proposed in this paper is applicable to calculate the Young's modulus in stepped shaft. The method can be further developed to detect mechanical parameters of more complicated structures using the combination of FEM simulation and RSM.

통계적 해석에 의한 유조선의 조타기 토오크 계산 경험식 개발 (A New Empirical Formula for Steering Gear Torque of Tankers by Statistical Analysis based on Sea Trial Data and Modified Lifting Line Theory)

  • 손동익;이기표
    • 대한조선학회논문집
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    • 제37권1호
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    • pp.40-49
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    • 2000
  • 본 논문에서는 흔타를 장착한 유조선의 조타기 토오크를 초기 설계 단계에서 추정할 수 있는 경험식을 통계분석 방법을 사용하여 개발하였다. 흔타의 타단독 상태에서의 유체역학적 특성은 Molland의 수정 양력선 이론에 따라 계산하였고, 선미 와류 내의 추진기와 선체의 영향은 실적선 자료의 회귀 분석을 통하여 추정하였다. 끝으로 본 방법에 의해 얻어진 조타기 토오크 추정경험식을 실적선에 적용한 후 그 결과를 비교하였으며, 매우 유의성이 높음을 확인하였다.

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비상발전기용량 산정식 개선에 관한 연구 (A Study on the Improvement of the Arithmetic for Emergency Generator Capacity)

  • 이종혁;김진오
    • 전기학회논문지
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    • 제67권11호
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    • pp.1517-1522
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    • 2018
  • This paper describes the improvement of the arithmetic for emergency generator capacity. This formula which calculates emergency generator is dependent on the Korean Design Standard of building electrical equipment issued by the Ministry of Land, Infrastructure and Transport, and the technical data related to the generator. when appling the formula, the capacity of the generator is insufficient at the starting conditions of the load facility. In case of emergency, the generator is not operated normally. $PG_2$ of the formula ($PG_1$, $PG_2$, $PG_3$) applied in determining the capacity of the emergency generator is selected by calculating the capacity of the generator based on only biggest one motor among the load equipment and $PG_3$ may not be able to start the generator normally in case of emergency because there is an error such that the power factor is applied at the last start of the motor having the maximum capacity of the load. We analyze the problem of capacity calculation of emergency generators used for general purposes. As a consequence, the improved formulas have been presented for safety of electrical installation.

국내 해성점토의 비배수 전단강도 분석을 통한 설계 적용성 평가 (Assessment on Design Applicability of Analysis of the Undrained Shear Strength in Korea Coastal Marine Clay)

  • 김명환;송창섭
    • 한국농공학회논문집
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    • 제58권1호
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    • pp.61-71
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    • 2016
  • This study performed the physical and mechanical experiment on the samples of costal marine clays individually collected in western and southern regions to identify the characteristics of western and southern costal marine clay. Based on the experiment result, the characteristics of costal marine clay is identified undrained shear strength. Based on the experiment result on the physical and mechanical characteristics of costal marine clays, the regression is presented that can analyze the mechanical characteristics of undrained shear strength in costal marine clay of Korea, region of Korea and western-southern region. The correlation of uniaxial compressive strength and undrained shear strength was suitable for use of western-southern region correlation equation. The test result of Jeonnam Yeosu area compares with prediction results of previous researchers formula and western-southern region formula. Prediction results appear highest reliability on the 0.827 of coefficient of determination in the prediction results of the western-southern region formula.

지역난방용 매설배관의 열응력 흡수에 관한 연구 (A Study on the Absorption of Thermal Stress on the Underground piping for the District heating)

  • 공재향;신병국
    • 한국공작기계학회논문집
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    • 제14권1호
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    • pp.81-88
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    • 2005
  • There have been many studies on generation equipment and plant piping, but there is no significant study result on the heat transportation pipe. As such, this study established basic theory on the compensated method among buried pipe for regional heating, and further obtained the following results by applying the conditions of AGFW and NCHPP respectively in calculation of friction and maximum installation distance for the buried pipe. Friction coefficient according to the types and physical properties of soil, friction and maximum installation distance were compared to set the application value of friction coefficient according to the location of works. Calculation formula of clay load to be applied for calculation of friction was introduced to the formula of AGFW and the formula of NCHPP that has been used in Nowon district since 1997 to determine the difference and applicability. $120^{\circ}C$ and $95^{\circ}C$ were applied in temperature difference for expansion volume to compare the arm length at the curve pipe so thai it can be reflected in the design in the future. Maximum installation distance according to thickness of pipe was compared to present the necessity of unified specification so that same kinds of pipe materials can be used for same kinds of works.