The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Vibration signals generated from rotating machinery fault sources are essentially random processes consisting of large amount of fault impulses, which belong to a special class of statistical distribution called α stable distribution. In this paper, a blind source separation method based on the utilization of fractional lower order statistics derived from the α stable distribution is proposed for...
The analysis method for regression model with unequally spaced time series error is presented, which is based on the relationship between the Green function of continuous system and the autoregression parameters of the time series. The conditional maximum likelihood estimation and exact maximum likelihood estimation of parameters of the regression model with unequally spaced correlated error are discussed...
Considering the difficulties such as the complicated process, the obtaining of clues and the complex calculation, a new method of Sneak Circuit Analysis is presented. The artificial neural network model is used to analyze the electrical system topographies and forecast the output of the system under the unknown input, and identify the sneak condition. The method is mainly based on Back-Propagation...
It has already been realized that the main external factor of MOSFET degradation or deviation from an expected normal condition is the time stress such as work and environment stresses. This paper introduced a real-time damage assessment method for MOSFET based on time stress analysis and failure models. And then, A health state assessment method was researched based on real-time damage information...
The reuse of electronics has a huge impact on environment, consumers, and manufacturers. With today's trend toward protecting the environment, sustainable development, and green engineering, more electronics are being reused and recycled, especially for consumer electronics. In this study, we developed a system dynamic model that focuses on the macro impact of the reuse of electronics on society at...
Theoretical basis and basic computational algorithms of PHM monitoring system are described. The architecture of PHM monitoring and realization of a market model are discussed based on the theoretical basis and the experience of PHM monitoring commercialization.
Electronic equipments propose the higher requirements for the performance and reliability of SMPS because of its continuous development. In the core components of SMPS, MOSFET and aluminum electrolytic capacitor are the key components that affect its reliability, and they have a higher failure and degradation rates among all of the components. Therefore, it is important to have a failure analysis...
Aimed at the characteristics of high-reliability and high test cost of armored equipment chassis, the reliability evaluation based on performance degradation data is proposed. First of all, the performance degradation model is improved by Bayes analysis with small sample, then the formula of reliability is deducted combined with the calculation of posterior distribution. Finally, the validity of this...
As an important element in condition-based maintenance (CBM) of complex engineering systems, remaining useful life (RUL) prediction has attracted much attention over the last decade. Since the degradation process of a system is uncertain over time as being well recognized, the resultant RUL is random in nature and the uncertainty needs to be quantified in the prediction. It is well known that higher...
Failure mechanism consistency means products failure mechanisms maintain unchanged at different stress levels, which is essential for estimated lives conversion between different stresses. In engineering, it is very popular to derive usage life from high stress accelerated tests for long life products, and identification of failure mechanism consistency is a key approach to solve this problem. In...
This paper deals with an estimation of the Remaining Useful Life of bearings based on the utilization of Mixture of Gaussians Hidden Markov Models (MoG-HMMs). The raw signals provided by the sensors are first processed to extract features, which permit to model the physical component and its degradation. The prognostic process is done in two phases: a learning phase and an evaluation phase. During...
Helicopter is a system on which operates a large number of specialities from electrical domain to mechanical domain. Today, diagnosis methods are segmented by field of expertise. Each expert treats the sub-system whose he is responsible for regardless of the results of other specialities. Therefore, there is no relation between specialities. Thus, diagnosis at system level is efficient but, due to...
BIT's false alarm is one of the most important reasons of restricting testability's development. In order to decrease BIT's false alarm and develop BITE's performance, this paper discusses present situation of BIT's false alarm at first, then introduces several advanced models of reducing false alarm which are neural network, support vector machine, fuzzy clustering analysis and hidden Markov model...
The objective of this paper is to propose a maintenance strategy for aluminum electrolytic capacitors based on the degradation model. According to the physical structure, this paper gives the equivalent circuit model and studies the main degradation mechanism. The degradation parameter is discussed in detail in the equivalent circuit model, and the failure criterion is determined about the ESR and...
As a significant PHM (Prognostics and Health Management) complement, testability is getting much more recognition. But correlations exit between testability parameters, and result in repeated work during testability designing process. First the origin of testability parameters and the effects that are brought by the parameters on design are studied, and some research premises are set up. Then the...
Taking the response data caused by the single event transient effects (SET) simulated by laser test facility and based on the optocoupler for example, this paper adapts sliding FFT method to analyze the response data. Analytical results indicate the method could quickly and correctly implement fault location. Therefore, more time could be saved to take necessary protective measures.
The maintenance review board report (MRBR) must be made before civil aircraft's operation. According to the status of lack of the used data and experience, the method to make the MRBR was proposed for developing civil aircraft on the basis of similar aircraft's experience and maintenance steering group conception. The method of making MRBR is based on the case-based reasoning (CBR). The structure...
The study on how to use the water medium replacing mineral oil as the lubricating medium of the ship propulsion system, is the high efficient energy-saving of the mechanical transmission system and the frontage of the environmental protection scientific research. The water lubricated rubber stern tube bearing is a very important supporting part of the ship propulsion system, its reliability life will...
Structural health monitoring is a new research focus and has being paid more and more attention in engineering. Based on the traditional NDT, SHM improve the ability of faults detection, diagnosis and prognostics. Especially in aeronautics, SHM has been applied to monitor the aircraft status and guide its maintenance, with the aim to improve its reliability, safety and reduce the cost. The faults...
Application of electronic devices in automotive industry keeps increasing and adoption of BGA assembly is inevitable in the industry. Vibrating environment in a vehicle provides another hazardous stress to the BGA assembly in addition to thermal one. In this study, random vibration tests on a daisy-chained BGA assembly have been conducted with real-time monitoring of resistance. The change of resistance...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.