• Title, Summary, Keyword: 신뢰성해석

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Application of Importance Sampling to Reliability Analysis of Caisson Quay Wall (케이슨식 안벽의 신뢰성해석을 위한 중요도추출법의 적용)

  • Kim, Dong-Hyawn;Yoon, Gil-Lim
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.21 no.5
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    • pp.405-409
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    • 2009
  • Reliability analysis of coastal structure using importance sampling was shown. When Monte Carlo simulation is used to evaluate overturng failure probability of coastal structure, very low failure probability leads to drastic increase in simulation time. However, importance sampling which uses randomly chosen design candidates around the failure surface makes it possible to analyze very low failure probability efficiently. In the numerical example, failure probability of caisson type quay wall was analyzed by using importance sampling and performance according to the level of failure probability was shown.

Reliability-based Design Optimization using MD method (곱분해기법을 적용한 신뢰성 기반 최적 설계)

  • Lee, Tae-Hee;Kim, Tae-Kyun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.101-104
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    • 2009
  • 최적설계는 설계자가 요구하는 제한조건을 만족시키는 범위에서 목적함수가 최소가 되는 설계점을 찾는 방법이다. 그러나 기존의 최적설계는 불확실성의 영향을 고려하지 않아 최적해가 제한조건의 경계에 위치하고 이것은 모델링과정이나 가공 등으로 인한 오차에 대한 영향을 고려하지 않는 문제점이 있다. 신뢰성 기반 최적설계는 불확실성을 정량화하면서 신뢰도를 계산하는 신뢰도 해석과정과 최적설계과정을 포함한다. 일반적으로 신뢰성 해석은 크게 추출법, 급속 확률 적분법, 모멘트 기반 신뢰성해석이 있다. 가장 널리 사용되는 급속 확률 적분법 중 최대 손상 가능점(MPP) 방법은 많은 MPP점이 존재하는 경우 수치적 비용이 증가하는 문제점과 표준 정규분포 공간으로 변환하는 과정에서 제한조건의 비선형성을 증가시켜 큰 오차를 발생시키는 문제점이 있다. 본 논문에서는 RBDO를 수행하기에 앞서 선행되어야 할 신뢰성해석 방법으로 곱분해기법을 사용하였고 이로부터 민감도 정보를 유도하여 기울기 기반 최적화 알고리즘을 적용하였다.

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The Stochastic Finite Element Analysis and Reliability Analysis of the Cable Stayed Bridge Considered to Correlation of the Random Variable (확률변수의 상관성을 고려한 사장교의 확률유한요소해석 및 신뢰성해석)

  • Han, Sung Ho;Shin, Jae Chul
    • Journal of The Korean Society of Civil Engineers
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    • v.26 no.1A
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    • pp.21-33
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    • 2006
  • The reliability analysis can be conducted more effectively by formulating the stochastic finite element method suitable for the reliability theory about the cable stayed bridge. After conducting the initial equilibrium analysis of the cable stayed bridge, the program which can conduct the linear and nonlinear stochastic finite element analysis using the perturbation method and the reliability analysis considered to the correlation of the random variable is developed. Using the results of this program about the cable stayed bridge, the characteristic of the node displacement, element force and cable tension according to the correlation of the random variable is investigated quantitatively. Also the reliability index and the failure probability are examined by the compounding the correlation of the random variable.

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Slope Stability Analysis Considering Multi Failure Mode (다중파괴모드를 고려한 사면안정해석)

  • Kim, Hyun-Ki;Kim, Soo-Sam
    • Journal of the Korean Society for Railway
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    • v.14 no.1
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    • pp.24-30
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    • 2011
  • Conventional slope stability analysis is focused on calculating minimum factor of safety or maximum probability of failure. To minimize inherent uncertainty of soil properties and analytical model and to reflect various analytical models and its failure shape in slope stability analysis, slope stability analysis method considering simultaneous failure probability for multi failure mode was proposed. Linear programming recently introduced in system reliability analysis was used for calculation of simultaneous failure probability. System reliability analysis for various analytical models could be executed by this method. For application analysis for embankment, the results of this method shows that system stability of embankment calculate quantitatively.

System Reliability-Based Safety Assessment of Steel Cable-Stayed Bridges (체계신뢰성방법에 기초한 강사장교의 안전도평가)

  • 조효남;임종권;박경훈
    • Computational Structural Engineering
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    • v.11 no.4
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    • pp.351-360
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    • 1998
  • 본 논문에서는 실용적 체계신뢰성에 기초한 강사장교의 안전도평가를 위한 체계적인 모형을 제안하였다. 공용중인 강사장교의 시스템 안전도평가를 위하여 요소신뢰성해석을 위한 케이블, 주형 그리고 주탑의 한계 상태모형과 각 요소들간의 조합파괴를 포함하는 주파괴경로를 정의할 수 있는 체계신뢰성해석 모형을 제안하였다. 요소신뢰성해석을 위한 수치해석기법으로는 AFOSM(Advanced First Order Second Moment) 방법을 사용하였고, 체계신뢰성해석을 위해서는 부분 ETA(partial Event Tree Analysis) 모형을 사용하였다. 제안된 방법의 타당성을 고찰하기 위하여 진도대교의 안전도 평가에 적용하였다. 부분 ETA 모혀을 사용한 체계신뢰성 평가 방법은 기존의 요소신뢰성 방법에 비해 구조물의 여용성을 충분히 반영하는 상당히 합리적이며 실제적인 결과를 보여주는 실용적인 방법으로 판단된다.

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A Study on the Application of Simple Reliability Analysis for Soil Improvement (연약지반개량에 대한 신뢰성해석 간편법의 적용성 연구)

  • Jang, Yeon-Soo;Park, Joon-Mo
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.759-767
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    • 2009
  • Recently, there is a trend to introduce a reliability approach to the design of al large scale improvement of weak ground due to the uncertainty of the influence factors in the consolidation. Since the reliability analysis is not easily adopted to geotechnical engineers because of some difficulties in working up the theories, Duncan(2000) proposed a simplified method for using reliability method to goetechnical problems. In this study, the applicability of Duncan's simplified reliability approach is evaluated by comparing the traditional reliability results with Duncan's. In the sensitivity analysis, the two results were quite similar. However, the probability of failure showed an error range of 20~50% and further Duncan's approach could not make a distinction for the distribution of geotechnical random variables. The simplified reliability method seems to be used properly in preliminary design if it is used supplementary with the deterministic method.

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Akaike Information Criterion-Based Reliability Analysis for Discrete Bimodal Information (바이모달 이산정보에 대한 아카이케정보척도 기반 신뢰성해석)

  • Lim, Woochul;Lee, Tae Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.12
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    • pp.1605-1612
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    • 2012
  • The distribution of a response usually depends on the distribution of the variables. When a variable shows a distribution with two different modes, the response also shows a distribution with two different modes. In this case, recently developed methods for reliability analysis assume that the distribution functions are continuous with a mode. In actual problems, however, because information is often provided in a discrete form with two or more modes, it is important to estimate the distributions for such information. In this study, we employ the finite mixture model to estimate the response distribution with two different modes, and we select the best candidate distribution through AIC. Mathematical examples are illustrated to verify the proposed method.

Basic Study on the Reliability Analysis of Structural Systems (시스템 신뢰성 해석에 관한 기초연구)

  • Lee, Joo-Sung
    • Journal of Ocean Engineering and Technology
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    • v.3 no.2
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    • pp.145-157
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    • 1989
  • 본 논문의 주목적은 불연속 또는 연속계 구조물의 시스템 신뢰성해석(system reliability analysis)을 위한 보다 일반적인 방법을 소개하는데 있다. 본 논문에서는, 확대하중증분법(extended incremental load method)이라고 불리우는데, 지금까지의 신뢰성 해석법 중 종래의 하중증분법이 갖는 단점을 보완하고, 여러 형태의 하중이 작용하는 구조물에 대해, 부재의 파괴후 거동(post-ultimate behaviour)을 다른 방법보다 더 실제적으로 고려할 수 있는 장점을 갖도록 개발한 것이다. 본 방법의 또 하나의 장점은 구조설계시 사용하는 강도공식(strength formula) 을 시스템 신뢰성 해석에서 직접 이용할 수 있다는 점이다. 이 방법은 부유식 해양구조물 같은 연속계 구조물의 시스템 신뢰성 해석을 위해 개발되었는데, 이 논문에서는 실제 구조물은 다루지 않고, 방법의 정당성과 아울러 수정된 안전여유식의 적용가능성을 보여주는 것에 중점을 두었다. 본 논문의 부유식 해양구조물들에 적용한 결과는 후일 발표할 예정이다.

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The Integrity Assessment Method of Initailly Cracked Structural Components by Reliability Analysis (신뢰성해석에 의한 초기균열을 갖는 구조부재의 건전성 평가방법)

  • S.J. Yim;T.U. Byun
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.2
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    • pp.161-176
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    • 1993
  • For the purpose of assessing structural integrity at a level of complexity and accuracy appropriate for the situation, integrity assessment methods are formulated with the following methods. One is three-tier assessment method of the revised BSI PD 6493 which considers stable crack growth effect, the others are limit load analysis which estimates the plastic collapse load and stability assessment method which considers stable crack growth of ductile material exactly using J-integral and tearing modulus. Besides, integrity assessments for center cracked panel(CCP) specimen and the circumferential through-cracked pipe are carried out and reliability analysis is accomplished by the first order reliability method which is one of the conventional reliability methods. Also the accuracy of the present method is verified by Monte Carlo method.

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Ship Structural Reliability Analysis by Probabilistic Finite Element Method (확률 유한요소법에 의한 선체 구조 신뢰성해석)

  • S.J. Yim;Y.S. Yang;J.H. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.28 no.2
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    • pp.241-250
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    • 1991
  • The reliability analysis for web frame of tanker is carried out by the probabilistic finite element method combined with the classical reliability method such as MVFOSM and AFOSM which can be used for calculating the probability of failure for the complicated structures in which the limit state equation is implicitly expressed. As random variables external load, elastic modulus, sectional moment of inertia and field stress are chosen and Parkinson's iteration algorithm in AFOSM is used for reliability analysis. By adding only the covariance data of the random variables to the input data set required for conventional finite element method, the present method can easily calculate the probability of failure at every element end as well as the covariances of structural reponses such as displacements at every element end and member forces at every element, even for the complicated ship structure.

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