scholarly journals Reliability modeling for competing failure systems with instant-shift hard failure threshold

2018 ◽  
Vol 42 (4) ◽  
pp. 457-467 ◽  
Author(s):  
Jingyi Liu ◽  
Yugang Zhang ◽  
Bifeng Song
Keyword(s):  
Sensitivity Analysis ◽  
System Reliability ◽  
Reliability Model ◽  
External Shocks ◽  
Reliability Modeling ◽  
Soft Failure ◽  
Random Shock ◽  
Hard Failure ◽  
Engineering Practices ◽  
Random Shocks

Many researchers have modeled systems under multiple dependent competing failure processes (MDCFP) in recent years. Typically, those failure processes consist of degradation (soft failure) and random shock (hard failure). In previous papers the threshold of hard failure has been a fixed value, which does not reflect engineering practices. Threshold refers to the ability to resist external random shocks, which shifts with time as the system is used. Thus, this paper establishes a model for MDCFP with instant-shift hard threshold. The hard failure threshold changes with time instantaneously, and it is also influenced by external shocks. This paper also presents a system reliability model. The effectiveness of the presented model is demonstrated by a reliability analysis of the micro-engine at Sandia National Laboratories. In addition, a sensitivity analysis is performed for specific parameters.

scholarly journals Reliability Modeling for Humidity Sensors Subject to Multiple Dependent Competing Failure Processes with Self-Recovery

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2714 ◽  
Author(s):  
Jia Qi ◽  
Zhen Zhou ◽  
Chenchen Niu ◽  
Chunyu Wang ◽  
Juan Wu
Keyword(s):  
Reliability Model ◽  
Humidity Sensors ◽  
Reliability Modeling ◽  
Reliability Models ◽  
Soft Failure ◽  
Recent Developments ◽  
General Reliability ◽  
Hard Failure ◽  
Mechanism Of Failure ◽  
Random Shocks

Recent developments in humidity sensors have heightened the need for reliability. Seeing as many products such as humidity sensors experience multiple dependent competing failure processes (MDCFPs) with self-recovery, this paper proposes a new general reliability model. Previous research into MDCFPs has primarily focused on the processes of degradation and random shocks, which are appropriate for most products. However, the existing reliability models for MDCFPs cannot fully characterize the failure processes of products such as humidity sensors with significant self-recovery, leading to an underestimation of reliability. In this paper, the effect of self-recovery on degradation was analyzed using a conditional probability. A reliability model for soft failure with self-recovery was obtained. Then, combined with the model of hard failure due to random shocks, a general reliability model with self-recovery was established. Finally, reliability tests of the humidity sensors were presented to verify the proposed reliability model. Reliability modeling for products subject to MDCFPs with considering self-recovery can provide a better understanding of the mechanism of failure and offer an alternative method to predict the reliability of products.

scholarly journals Reliability Evaluation of Multiple DCFP System subject to Shifting Threshold

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Chunping Li ◽  
Huibing Hao ◽  
Fang Xu ◽  
Guotao Zhao
Keyword(s):  
Wiener Process ◽  
System Reliability ◽  
Failure Process ◽  
Reliability Evaluation ◽  
Probabilistic Methods ◽  
Reliability Models ◽  
Soft Failure ◽  
Evaluation Models ◽  
Hard Failure ◽  
Random Shocks

This paper focuses on system reliability analysis with dependent competing failure process due to soft failure and hard failure. Some new probabilistic methods based on cumulative shock model and nonlinear Wiener process under different shifting thresholds situation are obtained. Considering that nonlinearity exists extensively in practice, the continuous soft failure process is governed by random effected nonlinear Wiener process. Firstly, reliability evaluation models for hard failure and soft failure are obtained under the cumulative shock, respectively. Furthermore, some system reliability models under different shifting thresholds situation are studied, in which failure threshold will decrease after a certain number of shocks. A real numerical example about fatigue crack growth dataset is carried out to demonstrate the proposed procedure. Numerical results indicate that both random shocks and shifting threshold have significant effect on system reliability. Finally, some sensitivity analysis are also been given.

Reliability and maintenance modeling for competing failures with intermission considered

2019 ◽  
Vol 233 (5) ◽  
pp. 898-907
Author(s):  
Jingyi Liu ◽  
Yugang Zhang ◽  
Bifeng Song
Keyword(s):  
System Reliability ◽  
Rest Period ◽  
Maintenance Cost ◽  
Reliability Model ◽  
Maintenance Policy ◽  
General Applicability ◽  
Industrial Systems ◽  
Soft Failure ◽  
Long Run ◽  
Degradation Failure

There are many industrial systems experiencing multiple dependent competing failure processes, in detail degradation failure (soft failure) and catastrophic failure (hard failure). Earlier research studied failure behaviors and system reliability during operational period, but did not consider the intermission period. Some industrial systems are not always operating continuously while with intermissions or rest period. The degradation and random shock processes are different between operating period and intermissions, which caused it more challenging and complicated to establish reliability model. In this article, a new reliability model for multiple dependent competing failure processes is developed with intermission considered. The system reliability can be analyzed based on the proposed model more practically. Besides, a preventive replacement maintenance policy is studied by minimizing the average long-run maintenance cost with intermission periods considered. Finally, the availability and general applicability of presented model are demonstrated by a case in different parameter settings.

scholarly journals Analysis and Application of Mechanical System Reliability Model Based on Copula Function

2016 ◽  
Vol 23 (s1) ◽  
pp. 187-191 ◽  
Author(s):  
Hai An ◽  
Hang Yin ◽  
Fukai He
Keyword(s):  
Mechanical System ◽  
System Reliability ◽  
Reliability Function ◽  
Copula Function ◽  
Reliability Model ◽  
Reliability Modeling ◽  
Modeling And Analysis ◽  
Copula Theory ◽  
Model Based ◽  
Analysis Process

Abstract There is complicated correlations in mechanical system. By using the advantages of copula function to solve the related issues, this paper proposes the mechanical system reliability model based on copula function. And makes a detailed research for the serial and parallel mechanical system model and gets their reliability function respectively. Finally, the application research is carried out for serial mechanical system reliability model to prove its validity by example. Using Copula theory to make mechanical system reliability modeling and its expectation, studying the distribution of the random variables (marginal distribution) of the mechanical product’ life and associated structure of variables separately, can reduce the difficulty of multivariate probabilistic modeling and analysis to make the modeling and analysis process more clearly.

Study of Reliability Modeling for Process System

2011 ◽  
Vol 199-200 ◽  
pp. 445-448
Author(s):  
Kun Lun Zhang ◽  
Bo Guo ◽  
Ping Jiang
Keyword(s):  
System Reliability ◽  
Error Propagation ◽  
Quality Parameter ◽  
Reliability Model ◽  
Design Requirement ◽  
Reliability Modeling ◽  
Whole Process ◽  
Process Reliability ◽  
Process System ◽  
Definition Of

The definition of process system reliability was provided. The study focused on the process reliability model with the quality parameter as index. Taking into account the effect of error propagation in working procedures on the whole process, it proposed the calculating methods of working procedures and process system reliability, which can effectively evaluate the ability of process subsystem in fulfilling design requirement.

Reliability modeling and analysis for systems governed by multiple competing failures processes

2020 ◽  
pp. 1748006X2097447
Author(s):  
Hongda Gao ◽  
Dejing Kong ◽  
Yixin Sun
Keyword(s):  
Process Model ◽  
Failure Modes ◽  
Failure Process ◽  
Extended Model ◽  
Reliability Modeling ◽  
Modeling And Analysis ◽  
Soft Failure ◽  
Shock Process ◽  
Hard Failure ◽  
Reliability Systems

Due to that the operating environment is becoming more and more complex and rigorous, the multiple competing failure modes for the reliability system is much commonly seen. In order to improve the system performance, a sensor-based degradation calibration policy (SBDC policy) is presented in this paper. The model considers the competing failure process which is described by the soft and hard failure modes. In detail, the soft failures occur when the degradation of the system exceeds the failure threshold, and the hard failures are caused by the same shock process. We use the Wiener process model to describe the soft failure and the shock process to describe the catastrophic failure. Meanwhile, in the shock process, the damage associated with the system is normal distributed which is related to the duration of the adjacent shocks. This extended model with calibrations has a good application value for the corresponding complex reliability systems which are subject to the dependent competing failure modes. By the model in this article, the system reliability and safety can be improved and the risk of the abrupt damage shall be reduced as the circumstance changes.

Coupling Effects and Sensitivity Analysis for Graycale System Reliability

2007 ◽  
Author(s):  
Tomonori Honda ◽  
Erik K. Antonsson
Keyword(s):  
Sensitivity Analysis ◽  
System Reliability ◽  
System Performance ◽  
Coupling Effect ◽  
Traditional Approach ◽  
Design Criteria ◽  
Reliability Modeling ◽  
New Approach ◽  
Mass Spring ◽  
Continuous Range

Understanding of the risk and reliability of systems can be enhanced by modeling the grayscale degradation of the performance of components and determining the grayscale impact on the system performance. Rather than producing an estimate of the probability of the system being in either the working or the failed state, as more traditional risk and reliability modeling does, this approach produces estimates of the probability of the system being in any of a continuous range of states between fully working and completely failed. In this paper, earlier work is extended by exploring the cause of major differences between this new approach and traditional reliability analysis, as well as by developing sensitivity analysis for grayscale reliability. Because the coupling effect can cause significant differences between this approach and the traditional approach, the coupling effect of component degradation is explored through the examples of coupled and decoupled mass-spring-damper systems. Also, a new sensitivity measure for grayscale reliability is developed to determine how designers can trade changes in reliability with other design criteria such as cost.

Reliability analysis for systems subject to mutually dependent degradation and shock processes

2021 ◽  
pp. 1748006X2110114
Author(s):  
Lina Bian ◽  
Guanjun Wang ◽  
Fengjun Duan
Keyword(s):  
Failure Modes ◽  
Failure Process ◽  
Analytical Techniques ◽  
Reliability Function ◽  
External Shocks ◽  
Reliability Indices ◽  
Soft Failure ◽  
Proposed Model ◽  
Mean Lifetime ◽  
Hard Failure

This paper studies the reliability problem for systems subject to two types of dependent competing failure processes, that is, soft failure and hard failure processes. A soft failure happens when the total degradation of the system exceeds a given critical level, while a hard failure occurs when the accumulative shock load caused by shocks surpasses the hard failure threshold. These two failure processes are mutually dependent due to the fact that external shocks will bring sudden increments in the degradation of the system, and the total amount of degradation will decrease the hard failure threshold of the system. The system fails whenever either of these two failure modes happens. Assuming that the arrival of shocks follows a Poisson process, the reliability function of the system under cumulative shock model is derived by using some analytical techniques. Some important reliability indices, including the mean lifetime of the system, the expected number of shocks until system failure, the probabilities of soft and hard failures, are calculated explicitly. Moreover, a special case that the hard failure process and soft failure process are mutually independent is also discussed. Monte Carlo method is employed to calculate the multiple integrals existing in the expressions of reliability function and reliability indices. A numerical example of the Reinforced Concrete pier columns on sea bridge is presented to illustrate the proposed model.

Reliability Analysis on Competitive Failure Processes under Multiple Failure Modes

2013 ◽  
Vol 442 ◽  
pp. 257-263
Author(s):  
Hui Bing Hao ◽  
Chun Su
Keyword(s):  
Sensitivity Analysis ◽  
Reliability Analysis ◽  
System Reliability ◽  
Failure Modes ◽  
New Model ◽  
Degradation Processes ◽  
Independent Case ◽  
Failure Models ◽  
Random Shocks ◽  
The Impact

In this article, a new multiple competing failure models proposed, in which multiple degradation processes and random shocks are considered. The shocks have a significant impact on system reliability, and the system reliability under not considering the impact of shocks is much higher than the impact of shocks is considered. In addition, the influences of the correlation among different degradation processes are also considered in this article. We can find that the reliability with considering the dependent case is higher than the independent case reliability. Thus the dependence of the two degradation processes is non-negligible. A numerical example with reliability analysis and sensitivity analysis is discussed to illustrate the proposed the new model.

scholarly journals Reliability modeling for dependent competing failure processes with phase-type distribution considering changing degradation rate

2021 ◽  
Vol 23 (4) ◽  
pp. 627-635
Author(s):  
Hao Lyu ◽  
Shuai Wang ◽  
Xiaowen Zhang ◽  
Zaiyou Yang ◽  
Michael Pecht
Keyword(s):  
Degradation Rate ◽  
Failure Process ◽  
Survival Function ◽  
Interarrival Time ◽  
Reliability Model ◽  
Shock Model ◽  
Ph Distribution ◽  
Soft Failure ◽  
Phase Type ◽  
Hard Failure

In this paper, a system reliability model subject to Dependent Competing Failure Processes (DCFP) with phase-type (PH) distribution considering changing degradation rate is proposed. When the sum of continuous degradation and sudden degradation exceeds the soft failure threshold, soft failure occurs. The interarrival time between two successive shocks and total number of shocks before hard failure occurring follow the continuous PH distribution and discrete PH distribution, respectively. The hard failure reliability is calculated using the PH distribution survival function. Due to the shock on soft failure process, the degradation rate of soft failure will increase. When the number of shocks reaches a specific value, degradation rate changes. The hard failure is calculated by the extreme shock model, cumulative shock model, and run shock model, respectively. The closed-form reliability function is derived combining with the hard and soft failure reliability model. Finally, a Micro-Electro-Mechanical System (MEMS) demonstrates the effectiveness of the proposed model.

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