Reliability Analysis and Prediction on Tunnel Roof under Blasting Disturbance

Pengfei Wu,Tianjiao Yang,Weichao Jia 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.9

The parameters of underground structure have the characteristics of large spatial heterogeneity and strong uncertainty. Recently, people gradually begin to use the idea of probability to analyze the safety of underground structures. However, few articles analyze the dynamic response of structural reliability. In this paper, the reliability of tunnel roof under blasting disturbance is studied, and the influence of the number of disturbances and the distribution of random variables on the structural reliability is analyzed. The prediction model of structural reliability is proposed. The sensitivity of different parameters to the structural reliability is discussed. The results show that the traditional method of evaluating the structural safety status is more dependent on the design value of each parameter. However, the design value does not represent the true state of the structure in a completely accurate way, which will result in a certain deviation between the assessment of the structural safety state and the actual state. Single disturbance has a limited impact on the structural reliability, while repeated disturbances can still have a noticeable effect on the structural reliability. When the disturbance reaches a certain number of times, the reliability of the structure can drop sharply. This paper proposes the prediction function of structure reliability according to the decay of structure reliability after blasting disturbance. Only a small number of parameters are needed to predict the structure reliability at different times. The error between the forecast results and the actual results is about 1%. With the increase of the number of blasting disturbances, the sensitivity coefficient of the structural resistance factor gradually decreases, and the sensitivity coefficient of the loaded effect gradually increases. The control of the blasting strength should be gradually increased to ensure the structural safety. Even if the mean and mean square error of random variables are the same, different distribution forms will have a great impact on the calculation results.

Reliability prediction of engineering systems with competing failure modes due to component degradation

손영갑 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.7

Reliability of an engineering system depends on two reliability metrics: the mechanical reliability, considering component failures, that a functional system topology is maintained and the performance reliability of adequate system performance in each functional configuration. Component degradation explains not only the component aging processes leading to failure in function, but also system performance change over time. Multiple competing failure modes for systems with degrading components in terms of system functionality and system performance are considered in this paper with the assumption that system functionality is not independent of system performance. To reduce errors in system reliability prediction, this paper tries to extend system performance reliability prediction methods in open literature through combining system mechanical reliability from component reliabilities and system performance reliability. The extended reliability prediction method provides a useful way to compare designs as well as to determine effective maintenance policy for efficient reliability growth. Application of the method to an electro-mechanical system, as an illustrative example, is explained in detail,and the prediction results are discussed. Both mechanical reliability and performance reliability are compared to total system reliability in terms of reliability prediction errors.

다목적 유전자 알고리즘기반 소프트웨어 모듈에 대한 신뢰성 할당 최적화

김국현(Gookhyun Kim),구태완(Taewan Gu),백종문(Jongmoon Baik) 한국정보과학회 2012 정보과학회논문지 : 소프트웨어 및 응용 Vol.39 No.3

소프트웨어 개발 초기 단계에서 소프트웨어 신뢰성 목표가 설정되면, 이 목표를 달성할 수 있도록 소프트웨어를 구성하는 각각의 하위 모듈들에 대한 신뢰성 목표를 설정해야 하며, 이 작업을 소프트웨어 신뢰성 할당이라고 한다. 이때 하위 소프트웨어 모듈들에 대한 신뢰성 목표를 설정하는 과정에서 고려해야 할 요소로는 개발 일정, 비용, 그리고 소프트웨어 신뢰성과 같은 요소들이 있다. 그럼에도 불구하고 기존 연구에서는 소프트웨어 신뢰성을 최대화 하거나 또는 개발 비용을 최소화 하는 오직 하나의 요소만을 고려하여 하위 소프트웨어 모듈들에 대한 신뢰성 목표를 설정하고 있다. 하지만 각 하위 소프트웨어 모듈들이 갖는 높은 상호 연관성 때문에, 하나의 요소만을 고려한 신뢰성 목표 할당은 최종 소프트웨어 신뢰성 목표를 달성하기 위한 적절한 방법이라 보기 어렵다. 그러므로 본 논문에서는 다목적 유전 알고리즘을 이용하여 소프트웨어 신뢰성과 예산을 고려하여 하위 소프트웨어 모듈 신뢰성 할당을 최적화 하는 기법을 제안한다. 또한 제안된 신뢰성 할당 기법을 사례 연구를 통해 프로젝트 관리자가 소프트웨어 신뢰성 할당 단계에서 전체 소프트웨어 신뢰성 목표와 비용을 동시에 고려한 균형 있는 신뢰성 할당을 할 수 있음을 제시한다. 본 연구는 비용을 최소화와 동시에 소프트웨어 신뢰성을 최대화 시켜 자원 이용의 효율성과 소프트웨어 신뢰성 목표 달성 정도를 극대화 시키는데 도움을 줄 수 있다. It is necessary to allocate software reliability for individual modules in the software system after software system reliability goal is established in the early development phase. Software reliability, cost, and schedule should be considered when we allocate software reliability. However, existing approaches tried to allocate software reliability with the maximization of software reliability or the minimization of cost. That is, the objective is only one. It is inappropriate approach to allocate software reliability which considers an objective because of high correlation among software modules. This paper proposes an approach to optimize software reliability allocation for software module with consideration of software reliability, cost, and schedule, which is based on multi-objective genetic algorithm. We also show project manager can achieve balanced software reliability allocation through a case study, which our approach is applied. Our approach helps to increase the efficiency of resource uses and maximize the degree of software reliability goal achievement.

발목관절 복합체의 가동범위 측정을 위한 중립위치와 측정방법의 신뢰도

홍완성,김기원,Hong, Wan-Sung,Kim, Gi-Won 대한물리치료학회 2011 대한물리치료학회지 Vol.23 No.4

Purpose: To determine the correct measurement methods of the ankle joint complex range of motion for measuring the neutral position and evaluate the rater reliability. In addition, the impact of training on the rater reliability was also assessed. Methods: The subjects were eleven healthy women, who were evaluated by two physical therapists and one physical therapist recorded the results of the study. Standard goniometer was used as the measurement tool. The ankle and subtalar joint neutral position and the active range of motion of the ankle and subtalar joint were measured. Intra-rater reliability and inter-rater reliability measures were analyzed with intraclass correlation coefficients. Results: Intra-rater reliability and inter-rater reliability ranged from high to medium for the neutral position of the ankle joint complex. Intra-rater reliability for dorsiflexion and plantarflexion measurements was medium, while the inter-rater reliability was high. The range of motion of the subtalar joint was measured, and the intra-rater reliability and inter-rater reliability were low and medium, respectively Also, the intra-rater reliability was increased with formal training of the measurement techniques. Intra-rater reliability was reduced in case the raters had not undertaken the training. Conclusion: In summary, the results obtained with the measurement tools and joint measurement of position, indicate the consistency of repeated measurements made by the same observers. Under the same circumstances along with repetition of the same measurement technique during training caused an increase in the rater reliability of formally trained raters.

Reliability growth analysis of <i>k-out-of-N</i> systems using matrix-based system reliability method

Byun, Ji-Eun,Noh, Hee-Min,Song, Junho Elsevier 2017 Reliability engineering & system safety Vol.165 No.-

<P><B>Abstract</B></P> <P>The advent of ever more complex systems in extensive areas of industries hampers efficient and accurate analysis of reliability and effective reliability-based decision making. Such difficulties may arise from the intricate formulation of system failure events, statistical dependence between component failure events, and the convoluted quantification of underlying probabilities of basic events. So-called <I>k-out-of-N</I> systems, which survive or succeed when at least <I>k</I> components are available among the total of <I>N</I> components, give rise to a high level of complexity. This type of systems are commonly introduced to secure a proper level of redundancy in operating engineering systems, but the intricate definition of the system events may elude the system reliability analysis. It is noted that such <I>k-out-of-N</I> systems are often tested and corrected over a certain period of time before their official usage or release in order to assure the target reliability of the system. For the purpose of reliability prognosis based on the data collected from the test period, reliability growth models (RGMs) have been widely used in software and hardware engineering. However, RGMs have been applied mostly to individual components, not at the system level. Furthermore, in complex systems such as <I>k-out-of-N</I> system, it is challenging to relate the reliability growth of components with that of the system. To address this need, in this paper, the matrix-based system reliability (MSR) method is extended to <I>k-out-of-N</I> systems by modifying the formulations of event and probability vectors. The proposed methods can incorporate statistical dependence between component failures for both homogeneous and non-homogeneous <I>k-out-of-N</I> systems, and can compute measures related to parameter sensitivity and relative importance of components. The reliability growths of components represented by RGMs are incorporated into the proposed system reliability method, so that the trend of <I>system</I> reliability growth can be effortlessly evaluated and predicted. Two numerical examples are introduced in this paper to demonstrate the proposed method and its applications: (1) hypothetical systems each consisting of series, parallel and <I>k-out-of-N</I> subsystems, and (2) a simplified high speed train system modeled by multiple <I>k-out-of-N</I> subsystems. Two types of RGMs, i.e. non-homogeneous Poisson process (NHPP) and Duane models are employed in these examples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MSR method is extended to evaluate the reliability growth of <I>k-out-of-N</I> systems. </LI> <LI> The time-varying reliability of system can be evaluated from that of components. </LI> <LI> The extended MSR method can account for statistical dependence between components. </LI> <LI> By-products of reliability analysis can support systematic decision-making. </LI> <LI> Numerical examples show the MSR method is applicable to various configurations. </LI> </UL> </P>

안전무결성 수준 및 MTTFd를 활용한 개발단계의 고성능 지상체 신뢰도 예측 방안

이민영,김상부,배인화,강소연,곽우영,이성근,오극기,최대림 한국산업융합학회 2024 한국산업융합학회 논문집 Vol.27 No.3

System reliability prediction in the development stage is increasingly crucial to reliability growth management to satisfy its target reliability, since modern system usually takes a form of complex composition and various complicated functions. In most cases of development stage, however, the information available for system reliability prediction is very limited, making it difficult to predict system reliability more precisely as in the production and operating stages. In this study, a system reliability prediction process is considered when the reliability-related information such as SIL (Safety Integrity Level) and MTTFd (Mean Time to Dangerous Failure) is available in the development stage. It is suggested that when the SIL or MTTFd of a system component is known and the field operational data of similar system is given, the reliability prediction could be performed using the scaling factor for the SIL or MTTFd value of the component based on the similar system’s field operational data analysis. Predicting a system reliability is then adjusted with the conversion factor reflecting the temperature condition of the environment in which the system actually operates. Finally, the case of applying the proposed system reliability prediction process to a high performance mooring platform is dealt with. ReliabilitSystem reliability prediction in the development stage is increasingly crucial to reliability growth management to satisfy its target reliability, since modern system usually takes a form of complex composition and various complicated functions. In most cases of development stage, however, the information available for system reliability prediction is very limited, making it difficult to predict system reliability more precisely as in the production and operating stages. In this study, a system reliability prediction process is considered when the reliability-related information such as SIL (Safety Integrity Level) and MTTFd (Mean Time to Dangerous Failure) is available in the development stage. It is suggested that when the SIL or MTTFd of a system component is known and the field operational data of similar system is given, the reliability prediction could be performed using the scaling factor for the SIL or MTTFd value of the component based on the similar system’s field operational data analysis. Predicting a system reliability is then adjusted with the conversion factor reflecting the temperature condition of the environment in which the system actually operates. Finally, the case of applying the proposed system reliability prediction process to a high performance mooring platform is dealt with.y Prediction, Safety Integrity Level, MTTFd, Scaling Factor, Conversion Factor

RELIABILITY-BASED SENSITIVITY ANALYSIS OF VEHICLE COMPONENTS WITH NON-NORMAL DISTRIBUTION PARAMETERS

Y. M. ZHANG,Z. YANG 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.2

Techniques from the perturbation method, fourth moment method, reliability based design theory, and sensitivity analysis approach are employed to present a practical and efficient method for testing the reliability sensitivity of vehicle components with non-normal distribution parameters. With the condition that the first four moments of original random variables are known, the reliability sensitivity theory and cases are researched using the presented numerical method. The variation regularities of reliability sensitivity are obtained and the effects of design parameters on reliability of the vehicle components are studied. The sophisticated formulation provided in this paper is easily amenable to computational procedures. The respective program can be used to obtain the reliability sensitivity of vehicle components with non-normal distribution parameters accurately and quickly. The results obtained are perfect and the solutions compared very well with those from Monte Carlo simulation. The method presents a theoretic basis for the reliability design of the vehicle components. Techniques from the perturbation method, fourth moment method, reliability based design theory, and sensitivity analysis approach are employed to present a practical and efficient method for testing the reliability sensitivity of vehicle components with non-normal distribution parameters. With the condition that the first four moments of original random variables are known, the reliability sensitivity theory and cases are researched using the presented numerical method. The variation regularities of reliability sensitivity are obtained and the effects of design parameters on reliability of the vehicle components are studied. The sophisticated formulation provided in this paper is easily amenable to computational procedures. The respective program can be used to obtain the reliability sensitivity of vehicle components with non-normal distribution parameters accurately and quickly. The results obtained are perfect and the solutions compared very well with those from Monte Carlo simulation. The method presents a theoretic basis for the reliability design of the vehicle components.

총 수명유지비를 고려한 무기체계 신뢰도 할당 모형

문미남,고선용,나호영,유권태 육군사관학교 화랑대연구소 2010 한국군사학논집 Vol.66 No.1

A minor defect in weapon systems such as aircraft, high-speed vehicle and nuclear power system, can cause fatal consequences. Thus, the weapon systems are requested high reliability to guarantee the use in the battlefield without any defects. Most of researches dealt with reliability maximization problem under considering the limited budget. But in practice, the majority of defense acquisition program go over their budget. Therefore, weapon developers have to consider the use of cost within the budget as well as reliability. Usually, reliability allocation problems are classified into two types :Maximization of the reliability within the budget and minimization of the cost with target reliability. In this research, unlike the previous two types of reliability allocation models which considered the initial acquisition cost in the phase of R&D, we suggest a new reliability allocation model which considers the maintenance costs after the force integration. Initial acquisition cost of weapon systems which have series and parallel mixed structure is expressed as a function,and Markov Chain model is used to calculate the expected value of maintenance cost which can be raised by fault repair and replacement. Based on that, we suggest a reliability allocation mathematics model of the objective function of total required costs optimization by nonlinear programing. In conclusion, we can figure out that, in case of weapon system acquisition program within the budget, the reliability allocation which optimize the maintenance costs while achieving target reliability with minimum cost is more efficient than traditional way of allocating reliability into sub-structures of weapon system with maximization of total reliability.

신뢰도 경로의 고장열거를 이용한 시스템 신뢰도 계산방법 연구

이장일(Jang-Il Lee),박기준(Kee-Jun Park),천환규(Hwan-Kyu Chun),정충민(Choong-Min Jeong),신동준(Dong-Jun Shin),서명원(Myung-Won Suh) 대한기계학회 2011 大韓機械學會論文集A Vol.35 No.6

항공기, 철도, 선박과 같은 대형 시스템들은 전기, 기계적으로 매우 복잡한 구조를 가졌으며 부품의 수명만을 고려한 기존의 유지보수에서 탈피하여, 고장분석의 시스템화를 통해 장치의 고유수명과는 관계없이 발생 가능한 우발고장도 대처할 수 있는 신뢰성 기반의 유지보수체계를 연구하여야 한다. 본 연구에서는 선행연구로 필요한 복합 시스템의 신뢰도 계산방법에 관한 연구이다. 복합 시스템의 신뢰도를 효과적으로 계산하기 위해 시스템의 RBD(Reliability Block Diagram)를 구성하고 인접행렬을 사용하여 RBD(Reliability Block Diagram)를 행렬로 표현한다. 또한 RBD(Reliability Block Diagram)행렬을 통하여 신뢰도 경로행렬과 고장열거 행렬을 구성하여 시스템의 신뢰도를 계산한다. 본 연구에서 제안한 알고리즘은 자동화, 시스템화가 가능하며 현재 개발하고 있는 신뢰도 정보관리 시스템 및 신뢰성 기반 유지보수 시스템에서 활용될 것이다. Recently, systems such as aircraft, trains and ships have become larger more complex. Therefore, the reliability calculation of these systems is more difficult. This paper presents a reliability calculation algorithm for a complex system with a solution that is difficult to analyze. When the system has a very complex structure, it is very difficult to find an analytical solution. In this case, we can assess system reliability using the failure enumeration method of the reliability path. In this research, we represent the reliability block diagram by an adjacent matrix and define the reliability path. We can find any system status by the failure enumeration of the reliability path, and thus we can calculate any kind of system reliability through this process. This result can be applied to RCM (Reliability-Centered Maintenance) and reliability information-management systems, in which the system reliability is composed of the reliabilities of individual parts.

기동장비 신뢰도 성장 관리 연구 : 발사대 체계 사례

이용준 ( Lee Yj ),배공명 ( Bae Gb ),허영무 ( Heo Ym ),서재현 ( Seo Jh ),김상부 ( Kim Sb ),최재경 ( Choi Jk ),박우재 ( Park Wj ) 한국품질경영학회 2017 품질경영학회지 Vol.45 No.4

Purpose: In this study, the reliability growth management procedures for armed vehicle is suggested and an illustrative case study of launcher system is given. Methods: Crow-AMSAA model is adopted to manage reliability growth of armed vehicle using failure data acquired from development test phase to field operation phase. Between the development test phase and the production phase, the suggested reliability growth procedures for armed vehicle entails accelerated life test of the selected module whose design is changed to improve its reliability for assuring the target system reliability. And it can be verified through estimating the system reliability based on the failure data of field operation phase. Results: It is shown that the proposed reliability growth management procedures are effective for armed vehicle based on the case study of launcher system. After estimating the reliability of launcher system at every development test, some items are selected to change their designs for improving reliability. Accelerated life test is performed to prove the reliability improvement and finally it is verified through the field operation. Conclusion: The reliability growth management procedures for armed vehicle is suggested and the case study of launcher system shows it can be effective for managing the reliability growth of the armed vehicle.