• Title/Summary/Keyword: Reliability design

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Reliability Analysis on GFRP Bridge Decks for Target Reliability (목표 신뢰성에 대한 GFRP 교량 바닥판의 구조 신뢰성 해석)

  • Kim, Sang-Jin;Kim, Jin-Kyu
    • Journal of the Korean Society of Industry Convergence
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    • v.10 no.1
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    • pp.47-54
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    • 2007
  • Bridge decks are one of the main structural components that are most suitable for utilizing the advantages of FRP materials due to the high strength weight ratio of FRP materials. Design codes for the design of FRP bridge decks should be established to apply FRP materials for bridge decks effectively. At present, design codes are relatively well established for the use of FRP materials as reinforcements in concrete structures. However, design codes have not yet been provided for the structures made of FRP as a main construction material. In this study, for the purpose of preparing design code provisions, reliability analyses were performed to evaluate target level of safety and serviceability on GFRP decks. Based on the results, several guidelines for the development of design codes are suggested.

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A New Sensitivity-Based Reliability Calculation Algorithm in the Optimal Design of Electromagnetic Devices

  • Ren, Ziyan;Zhang, Dianhai;Koh, Chang Seop
    • Journal of Electrical Engineering and Technology
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    • v.8 no.2
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    • pp.331-338
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    • 2013
  • A new reliability calculation method is proposed based on design sensitivity analysis by the finite element method for nonlinear performance constraints in the optimal design of electromagnetic devices. In the proposed method, the reliability of a given design is calculated by using the Monte Carlo simulation (MCS) method after approximating a constraint function to a linear one in the confidence interval with the help of its sensitivity information. The validity and numerical efficiency of the proposed sensitivity-assisted MCS method are investigated by comparing its numerical results with those obtained by using the conventional MCS method and the first-order reliability method for analytic functions and the TEAM Workshop Problem 22.

Evaluation of Highway Traffic Safety using Reliability Theory (신뢰도를 활용한 도로시설 교통안전성 평가기법)

  • Oh, Heung-Un
    • International Journal of Highway Engineering
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    • v.18 no.4
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    • pp.77-82
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    • 2016
  • PURPOSES : This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

Development of design framework based on reliability analysis using MATLAB (MATLAB 을 이용한 신뢰도 기반 설계 시스템 개발)

  • Sung, Young-Hwa;Kwak, Byung-Man;Maute, Kurt
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1642-1647
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    • 2007
  • The aim of this research is to implement a design framework based on reliability analysis and make it possibly used for a reliable and robust design under uncertainties. Different types of reliability methods and algorithms are programmed to explore their characteristics. In our work, RIA and the PMA are employed for formulating the reliability analysis problems. A number of reliability methods are introduced in this program such as FORM, AMV/AMV+ and MCS. Reliability analysis can be easily performed with this tool box only if a drive file is ready to run. Users need to select random design variables and define their distributions and correlation.

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Reliability-Based Optimal Design of Pillar Sections Considering Fundamental Vibration Modes of Vehicle Body Structure (차체 기본 진동 모드를 고려한 필러 단면의 신뢰성 최적설계)

  • Lee Sang Beom;Yim Hong Jae
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.6
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    • pp.107-113
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    • 2004
  • This paper presents the pillar section optimization technique considering the reliability of the vehicle body structure consisted of complicated thin-walled panels. The response surface method is utilized to obtain the response surface models that describe the approximate performance functions representing the system characteristics on the section properties of the pillar and on the mass and the natural frequencies of the vehicle B.I.W. The reliability-based design optimization on the pillar sections Is performed and compared with the conventional deterministic optimization. The FORM is applied for the reliability analysis of the vehicle body structure. The developed optimization system is applied to the pillar section design considering the fundamental natural frequencies of passenger car body structure. By applying the proposed RBDO technique, it can be possible to optimize the pillar sections considering the reliability that engineers require.

Reliability analysis of Industrial plant reinforced concrete columns

  • Cheng, Zhengjie;Yao, Jitao;Gao, Jun
    • Advances in concrete construction
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    • v.14 no.2
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    • pp.131-137
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    • 2022
  • Based on the design of reinforced concrete columns in Chinese design codes, the failure function of reinforced concrete (RC) columns cannot be expressed as a linear function. This makes it difficult to reveal the level of reliability control in Chinese design code. Therefore, the failure function of dimensionless form is established in this paper, and the typical components (Industrial plant columns) are selected for analysis. At last, numerical simulation proves that the proposed model can be used to analysis reliability of columns. The results based on this model indicate that there is a strong difference in the reliability of RC columns designed with different design parameters, and the reliability would be lower when the eccentricity produced by crane load is smaller.

New Approaches for Calibrating Material Factors of Reinforced Concrete Members in Korean Highway Bridge Design Code (Limit State Design) and Reliability Analysis (도로교설계기준(한계상태설계법)의 콘크리트부재 설계를 위한 재료계수 결정법 및 신뢰도 분석)

  • Lee, Hae Sung;Song, Sang Won;Kim, Ji Hyeon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.39 no.1
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    • pp.13-24
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    • 2019
  • This paper brings up fallacy of material factors specified for the design of concrete members in the current Korean limit state design code for highway bridges, and proposes new material factors based on a robust optimization scheme to overcome the fallacy. It is shown that the current load factors in the code and the proposed material factors lead to a much higher reliability index than the target index. The load factors are adjusted to yield the target reliability index using the inverse reliability analysis. A reliability-based approach following the basic concept of Eurocode is formulated to determine material factors as well as load factors. The load-material factors obtained by the proposed reliability-based approach yield a lower reliability level than the target index. Drawbacks of the basic concept of Eurocode are discussed. It is pointed out that differences in the uncertainties between materials and members may cause the lower reliability index of concrete member than the target.

A study on Reliability Analysis for Plane Frame Structure (평면뼈대구조의 신뢰성해석에 관한연구)

  • 이중빈;신형우
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1989.10a
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    • pp.34-39
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    • 1989
  • Recent trends in design standards development have encouraged the use of probabilistic limit sate design concepts. Reliability analysis adopted in those advanced countries have the potentials that they afford for symplifying the design Process arid placing it on a consistent reliability based for various construction materials. This study is proposed in the reliability analysis of plane frame structures using second-order moment method(Level-II they). Lind-Hasofer's minimum distance method is use in the derivation of an mathematical algorithm as well as an determination of Correlation cofficients, reliability index and total reliability index depending on the multiple failure modes. In addition. This study is employed as a practical tool for the approximate reliability analysis. Results of the numerincal analysis showed that the difference between the reliability index of the failure probability of the multiple failure modes and the total reliability index of the failure probability with the simultaneous failure modes deviated nearly 3∼10% depending on tile performance functions.

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System Structure and Reliability Optimization of VVVF Urban Transit Brake System Through Cost Function Construction (비용함수를 이용한 VVVF 전동차 제동장치의 시스템 구조 및 신뢰도 최적화)

  • Kim, Se-Hoon;Kim, Hyun-Jung;Bae, Chul-Ho;Lee, Jung-Hwan;Lee, Ho-Yong;Suh, Myung-Won
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.3
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    • pp.63-71
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    • 2007
  • During the design phase of a product, reliability and design engineers are called upon to evaluate the reliability of the system, The question of how to meet target reliability for the system arises when estimated reliability or cost is inadequate. This then becomes a problem of reliability allocation and system structure design. This study proposes the optimization methodology to achieve target reliability with minimum cost through construction of the cost function of system. In cost function, total cost means the sum of initial cost, repair cost and maintenance cost. This study constructs optimization problem about system structure design and reliability allocation using cost function. This problem constructed is solved by Multi-island Genetic Algorithm(MIGA), and applies to urban transit brake system. Current brake system of the urban transit is series system. Series system is the simplest and perhaps one of the most common system, but it demands high reliability and maintenance cost because all components must be operating to ensure system operation. Thus this study makes a comparative study by applying k-out-of-n system to brake system. This methodology presented can be a great tool for aiding reliability and design engineers in their decision-makings.