• Journal of Astronomy and Space Sciences
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• 제36권2호
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• pp.69-74
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• 2019

Spacecraft requires sufficient power in orbit to perform its mission. So as to comply with system requirements, the sufficient power should be made by a solar cell array by photovoltaic power conversion. A life time of space program depends on its mission considering parts reliability and parts grade. Based on the mission life time, power equipment might be designed to meet specifications. In outer space, solar cell array might generate the dc power by photovoltaic conversion effects and GaInP/GaAs/Ge solar cells are used in this study. Space programs that require more than five years should select parts for high reliability applications. Therefore, reliability analysis for high reliability applications should be performed to check its fulfilment of the requirements. This program should also require more five years for its mission and we performed its analysis using parts count method (PCM) for its reliability. Finally, we performed reliability analysis and obtained quantitative figures found out 99.9%. In this study, we presented the reliability analysis of the 300 W GaInP/GaAs/Ge solar cell array.

• 한국컴퓨터정보학회논문지
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• 제15권4호
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• pp.37-45
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• 2010

시간적 정확성을 필요로 하는 시스템은 신뢰성을 위하여 실행시간에 관한 정확한 설계와 검증이 필요하다. 따라서 실행시간의 분석을 위한 개발 지원 도구가 필요하고 이를 위한 많은 연구가 진행되고 있다. 이러한 개발 지원 도구의 분석 방법은 정적 분석 방법과 측정 기반 분석 방법의 두 가지로 구분된다. 먼저 정적 분석은 짧은 시간에 분석이 가능하지만, 다양한 하드웨어의 존재로 인해 I/O 정보 예측이 어려워 분석 결과의 신뢰성이 떨어진다. 두 번째로 측정 기반 분석은 실제 결과에 근접한 분석이 가능하지만, 사용하기 어렵고 분석에 걸리는 시간이 길다. 이러한 분석 방법의 문제를 해결하기 위하여 본 논문에서는 정적 분석 과정에 소프트웨어 감시 방안을 적용한 방법을 제안한다. 제안하는 분석 방안은 정적 분석을 통해 감시가 필요한 대상을 자동으로 결정하고 감시 결과를 통해 과대 예측을 줄일 수 있다. 따라서 감시에 대한 어려움과 시간의 부하를 줄이고 정적 분석의 가장 큰 문제점인 신뢰성을 향상시킬 수 있다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1994년도 봄 학술발표회 논문집
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• pp.199-208
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• 1994

One of the main objectives of the study is to propose a practical but realistic limit state model considering combined effect of axial and bending load for reliability analysis and safety assessment of cable-stayed bridge under vehicle traffic loads. This paper is intended to propose a new approach for the evaluation of reserved load carrying capacity of cable-stayed bridge under vehicle traffic loads in terms of equivalent strength, which may be defined as a bridge strength corresponding to the reliability index of the bridge. This can be derived from an inverse process based on the concept of FOSM form of reliability index. AFOSM and IST methods are used for the reliability analysis of the proposed models. The proposed reliability model and methods are applied to the safety assessment of Jindo Bridge which is one of major two cable-stayed bridges in Korea.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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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.

• 시스템엔지니어링학술지
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• 제4권1호
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• pp.35-43
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• 2008

Generally, in analysis of reliability of Design and Development Phase, reliability of electrical components is analyzed based on standards such as MIL-HDBK-217F, Bellcore Issue 4,5,6 by analyzing stress of architectural side (Power, Voltage, Current and quality level of components) of weapon system and stress of operational side (operational environment, operational temperature, Operational Profile). But the reliability of mechanical components is analyzed based on the data book of failure history of mechanical parts called NPRD-95(Nonelectronic Parts Reliability Data-95) without any analysis of above stress. However, even if it's the same mechanical parts, it might have different failure rate(fatigue, wear, corrosion) during operation depending on how weary(stress : pressure, vibration, temperature during operation) the parts are. Therefore, analyzing reliability using just data book can cause big difference in reliability instead of analyzing based upon stressfulness that parts might have, operational concept, and other various factors. Thus, This paper will guide the way of predicting reliability by organizing ways of predicting reliability for system organization and adopt ing NSWC-98/LE1(Naval Surface Warfare Center-98/LE1) for mechanical components.

• 시스템엔지니어링학술지
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• 제12권1호
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• pp.105-112
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• 2016

An aircraft must be designed to minimize system failure rate for obtaining the aircraft safety, because the aircraft system failure causes a fatal accident. The safety of the aircraft system can be predicted by analyzing availability, reliability, and maintainability of the system. In this study, the reliability and the maintainability of the hydraulic system are analysed except the availability, and therefore the reliability and the maintainability analysis process and the results are presented for a helicopter hydraulic system. For prediction of the system reliability, the failure rate model presented in MIL-HDBK-217F is used, and MTBF is calculated by using the Part Stress Analysis Prediction and quality/temperature/environmental factors described in NPRD-95 and MIL-HDBK-338B. The maintainability is predicted by FMECA(Failure Mode, Effect & Criticality Analysis) based on MIL-STD-1629A.

• 한국안전학회지
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• 제32권3호
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• pp.54-59
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• 2017

This paper presents an efficient finite analysis model and a simulation-based reliability analysis method for stowage device system failure of a container crane with respect to lateral load. A quasi-static analysis model is introduced to simulate the nonlinear resistance characteristics and failure of tie-down and stowage pin, which are the main structural stowage devices of a crane. As a reliability analysis method, a subset simulation method is applied considering the uncertainties of later load and mechanical characteristic parameters of stowage devices. An efficient Markov chain Monte Carlo (MCMC) method is applied to sample random variables. Analysis result shows that the proposed model is able to estimate the probability of failure of crane system effectively which cannot be calculated practically by crude Monte Carlo simulation method.

• Structural Engineering and Mechanics
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• 제55권3호
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• pp.525-534
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• 2015

A new structural dynamic fuzzy reliability analysis under stochastic loads which are applied several times is proposed in this paper. The fuzzy reliability prediction models based on time responses with and without strength degeneration are established using the stress-strength interference theory. The random loads are applied several times and fuzzy structural strength is analyzed. The efficiency of the proposed method is demonstrated numerically through an example. The results have shown that the proposed method is practicable, feasible and gives a reasonably accurate prediction. The analysis shows that the probabilistic reliability is a special case of fuzzy reliability and fuzzy reliability of structural strength without degeneration is also a special case of fuzzy reliability with structural strength degeneration.

• International Journal of Aeronautical and Space Sciences
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• 제16권4호
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• pp.510-519
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• 2015

Concerning the issue of high-dimensions, hybrid uncertainties of randomness and intervals including implicit and highly nonlinear limit state function, reliability analysis based on the hybrid uncertainty reliability mode combining with back propagation neural network (HU-BP neural network) is proposed in this paper. Random variables and interval variables are as input layer of the neural network, after the training and approximation of the neural network, the response variables are obtained through the output layer. Reliability index is calculated by solving the optimization model of the most probable point (MPP) searching in the limit state band. Two numerical cases are used to demonstrate the method proposed in this paper, and finally the method is employed to solving an engineering problem of the aerospace friction plate. For this high nonlinear, small failure probability problem with interval variables, this method could achieve a good analysis result.

• Computers and Concrete
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• 제29권1호
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• pp.59-67
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• 2022

In this paper, a reliability-based approach has been implemented to develop seismic analytical fragility curves of highway bridges. A typical bridge class of the Central and South-eastern United States (CSUS) region was selected. Detailed finite element modelling is presented and Incremental Dynamic Analysis (IDA) is used to capture the behavior of the bridge from linear to nonlinear behavior. Bayesian linear regression method is used to define the demand model. A reliability approach is implemented to generate the analytical fragility curves and the proposed approach is compared with the conventional fragility analysis procedure.