• 한국신뢰성학회지:신뢰성응용연구
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• 제15권3호
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• pp.145-148
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• 2015

The products to meet the requirement of are installed in nuclear power plant and the reliability target should be provided in the requirement. However, it is not easy to set a reliability target using quantitative analysis. The objective of this paper is to propose a method of reliability target setting considered warranty cost for process controller and then compare a reliability target with reliability analysis result.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권4호
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• pp.248-255
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• 2015

Purpose : The purpose of this research is to develop the optimized method and process in the reliability-growth target setting, especially for complex and repairable system (or products) such as vehicle and airplane, construction equipment. Method : A reliability-growth test plan specifies a scenario to achieve the planned reliability value (or reliability target). The major elements in test planning are reliability-growth starting time and reliability level at that time, reliability-growth rate and reliability-growth target. All of them except a reliability target can be referred to the previous development data and reference researches. The reliability target level is directly influencing to test period (or time) which is related to test and warranty cost together. There are a few researches about the reliability target setting method and but showing the limitations to consider the views of engineering, business and customer together. There is no research how to handle the target setting process in detail. Result : We develop the optimized method and systematic process in reliability target setting with considering such views. This research also establish the new concept as production capability which means company (or supplier) capability to product its products. Conclusion : In this research result, we apply the new method to a few projects and can set the reasonable test planning. The developing results is showing the good balance between the developing cost and warranty cost at market.

• 한국신뢰성학회지:신뢰성응용연구
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• 제13권3호
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• pp.175-190
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• 2013

This study considers reliability growth management as the excellent method for construction equipment development with the effect on decreasing COPQ(Cost of Poor Quality Cost) of new products. MIL-HDBK-189A(1981) and RADC-TR-84-20(1984) standards provide a general concept of reliability growth management including to reliability growth test, models and FRACAS(Failure Reporting and Corrective Action System). There is no study how to apply reliability growth management to construction equipment(or machine) development. This paper propose the method to apply it to construction equipment development process from the reliability target setting for developing products to launching them at market. It is expecially showing how to set target reliability for new developing equipment and the development risk to reach the reliability target in detail.

• 한국항공운항학회지
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• 제17권1호
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• pp.24-28
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• 2009

The reliability assessment is performed for Pressure Control Regulator of Aircraft Fuel System using reliability procedure which consists of the reliability analysis and the Failure Modes and Effects Analysis(FMEA). The target reliability as MTBF(Mean Time Between Failure) is set to 5000hr. During the reliability analysis process, the system is categorized by Work Breakdown Structure(WBS) up to level 3, and a reliability structure is defined by schematics of the system. Since the components and parts that have been collected through EPRD/NPRD. The predicted reliability to meet mission requirements and operating conditions is estimated as 4375.9hr. To accomplish the target reliability, the components and parts with high RPN have been identified and changed by analyzing the potential failure modes and effects. By changing the configuration design of components and parts with high-risk, the design is satisfied target reliability.

• International Journal of Automotive Technology
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• 제8권6호
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• pp.713-722
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• 2007

Design variables for suspension systems cannot always be realized in the actual suspension systems due to tolerances in manufacturing and assembly processes. In order to deal with these tolerances, design variables associated with kinematic configuration and compliance characteristics of suspensions are treated as random variables. The reliability of a design target with respect to a design variable is defined as the probability that the design target is in the acceptable design range for all possible values of the design variable. To compute reliability, the limit state, which is the boundary between the acceptable and unacceptable design, is expressed mathematically by a limit state function with value greater than 0 for acceptable design, and less than 0 for unacceptable design. Through reliability analysis, the acceptable range of design variables that satisfy a reliability target is specified. Furthermore, through sensitivity analysis, a general procedure for optimization of the design target with respect to the design variables has been established.

• Geomechanics and Engineering
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• 제15권3호
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• pp.879-888
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• 2018

Probability-based design codes have been developed to sufficiently confirm the safety level of structures. One of the most acceptable probability-based approaches is Load Resistance Factor Design (LRFD), which measures the safety level of the structures in terms of the reliability index. The main contribution of this paper is to calibrate the load and resistance factors of the design code for tunnels. The load and resistance factors are calculated using the available statistical models and probability-based procedures. The major steps include selection of representative structures, consideration of the limit state functions, calculation of reliability for the selected structures, selection of the target reliability index and calculation of load factors and resistance factors. The load and resistance models are reviewed. Statistical models of resistance (load carrying capacity) are summarized for strength limit state in bending, shear and compression. The reliability indices are calculated for several segments of a selected circular tunnel designed according to the tunnel manual report (Tunnel Manual). The novelty of this paper is the selection of the target reliability. In doing so, the uniform spectrum of reliability indices is proposed based on the probability paper. The final recommendation is proposed based on the closeness to the target reliability index.

• 한국철도학회논문집
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• 제14권1호
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• pp.6-10
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• 2011

본 연구는 정시성의 목표값이 운영 요구조건으로 주어지고 이를 달성하지 못한 해당연도에는 철도운영자에게 패널티가 부과되는 상황에서 철도시스템의 신뢰도 목표값을 설정하는 문제를 다룬다. 철도시스템의 신뢰도에 따라 총 운영기간동안 패널티 부과 회수가 달라지기 때문에 철도운영자는 이를 고려하여 철도시스템 및 하위시스템에 대해 신뢰도 목표값을 설정할 필요가 있다. 본 논문은 철도운영자가 운영기간 동안의 패널티 부과회수를 고려하여 철도시스템의 서비스 신뢰도 목표로 설정할 수 있도록 철도시스템 및 하위시스템의 서비스 고장 간 거리에 따라 연간 패널티 부과 확률 및 철도시스템의 운영연수 동안 패널티 부과 회수를 산출하는 절차 및 계산식을 제안한다.

• 한국지반환경공학회 논문집
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• 제15권2호
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• pp.5-15
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• 2014

목표신뢰도지수는 한계상태설계법에서 안전여유의 지표가 되며, 부분계수를 결정하는데 있어 매우 중요한 역할을 한다. 본 연구에서는 한계상태설계법에서 필요로 하는 목표신뢰도지수의 결정을 위하여 쇄석다짐말뚝이 적용된 6개소의 설계-시공사례를 조사하였다. 쇄석다짐말뚝의 주요 파괴모드인 팽창파괴에 대한 한계상태함수를 정의하고, 일계신뢰성해석법(FORM)을 이용하여 극한지지력, 이론식별, 신뢰도수준을 평가하였다. 현행 쇄석다짐말뚝의 신뢰도지수는 허용응력설계법에 의해 산정된 안전율과 비례하는 경향을 보였으며, 평균 신뢰도지수는${\beta}$=2.30으로 평가되었다. 신뢰성해석에 의해 평가된 신뢰도 수준과 기존 구조물 기초에 대한 목표신뢰도지수를 비교 분석한바, 쇄석다짐말뚝 기초는 말뚝기초 및 얕은기초에 비하여 비교적 낮은 안정성 수준이 요구되며, 쇄석다짐말뚝의 현재 신뢰도수준은 보강토옹벽, 쏘일네일링에서 제안된 목표신뢰도지수와 유사한 범위를 보이므로 쇄석다짐말뚝의 목표신뢰도지수를 ${\beta}_T$= 2.33으로 제안하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권1호
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• pp.29-35
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• 2014

To improve the reliability of a weapon system, we perform the activities: setting the target reliability, reliability allocation, and reliability management, etc. Before starting weapon system development, the target reliability of system is set through advanced research and is allocated to its subsystems at the beginning of development. Then we manage the reliability of system and subsystems to meet the target reliability until completion of system development. In this paper, we research representative reliability allocation methods and introduce the suitable reliability allocation method followed by its application to the underwater guided weapon system. The purpose of this research is to review the proposed reliability allocation techniques and find an appropriate method for underwater weapon systems followed by the validation of its application.

• 시스템엔지니어링학술지
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• 제17권1호
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• pp.1-10
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• 2021

In this paper we proposed the alternative analysis of reliability design using redundancy technique. First, we presented the process for establishing the reliability design alternative analysis process considering the active redundancy and the standby redundancy. and then, the case analysis of A driving equipment was performed in accordance with the reliability design alternative analysis process presented. In case the series reliability design result is not met with the reliability target value. so, the target item for redundancy design of A driving equipment were selected as items with a severity of two or higher. The redundancy design applied with active and standby redundancy techniques were analyzed using BlockSim software. As a result, it was analyzed that reliability design to active redundancy with one of two elements required for A driving equipment is the most efficient compared to the target value of reliability. The results of this study can be usefully used before the reliability design is performed.