Papers by Author: Hong Fu Zuo

Abstract: A new technique of aircraft structural health monitoring so-called Comparative Vacuum Monitoring (CVM) is introduced in this paper. Compared with the traditional and some novel Non-Destructive Testing (NDT) techniques, it is capable of real-time crack initiation and growth detection reliably and accurately, and especially suitable to monitor the interior locations with hard accessibility. With the advantages of this technique, the aircraft manufacturers (such as Boeing, Airbus, Bombardier, Embraer, ect.) are much interested in applying it into aircraft structural health monitoring and have carried out verification tests on aircrafts or technology ready for the future usage. Through the use of CVM technique, it is possible to quickly, routinely and remotely monitor the integrity of a structure in service.

Abstract: The principle of gas path electrostatic circular sensor was discussed in this paper, in addition, a monitoring experiment with self-made circular sensor was carried out on turbojet engine, and electrostatic signals were collected successfully to verify the validity and feasibility of the sensor. According to the signals monitored over 131h, typical signals of 233-240 phases were analyzed. It was proved that the unusual particles were caused by carbon deposition from fuel spray nozzle. Therefore, under real-time monitoring of gas path changes with electrostatic circular sensor, early warning could be provided for initial fault condition as well as real-time reference for condition-based maintenance.

Abstract: The MRBR is important to ensure the aircraft’s safety and reliability. The analysis to the structural components’ reliability is to establish the basis for its MRBR. The aviation component’s reliability obey the bathtub curve distribution, Weibull distribution, exponential distribution and a linear increasing distribution. A method of reliability analysis of structural components is proposed. According to the aircraft operating data the structural components reliability distribution is fitted. The component failure weaknesses and remedial measures can be determined according to its reliability distribution. So the perfect MRBR can be obtained. As an example the structural component slide rail is studied, which showed the slide rail reliability is the Weibull distribution and consistent with the actual running situation. So the example showed that the proposed method is reasonable. And a viable method to the development of aircraft MRBR is got.

Abstract: Due to compressor fouling, gas turbine efficiency decreases over time, resulting in decreased power output of the plant. To counteract the effects of compressor fouling, compressor on-line and off-line washing procedures are used. The present research is aimed to propose a method of mathematical modeling of offline washing interval which will be estimated as the RUL of compressor based on Proportional hazards model. Application of the proposed prediction method to the case of Civil Aero-engine proved its effectiveness.

Abstract: The concept of delay time and its maintenance theory are introduced, considering failure modes of system have different probability of occurrence and repair time, two revised model are established with the defects follow homogeneous processes and non-homogeneous process, The revised model could improve the expected unit downtime and optimize inspection interval.

Abstract: The slide rail of the airfoil is the key structural component of the aircraft, and its wear reliability has important impact to the aircraft security. The traditional method to the slide rail wear reliability analysis is based on time parameter to establish the reliability function. In fact, the actual operating and environmental parameters in the slide rails have an important impact on its reliability. The proportional hazards model (PHM) method is proposed to study the affecting factors of the slide rail’s wear reliability; the method of principal component is used to make a quantitative description to those affecting factors. and the slide rail’s reliability model of its failure function and life distribution function are obtained under many factors affecting. Finally, a study is made to the wear reliability of some regional jet’s slide rail with the PHM method; the wear reliability model is got under the contact stress, hardness and roughness three affecting factors which meet the fact. So the more accurate wear reliability models can be got by the PHM methods, and that has a practical significance to improve the overall reliability of the aircraft.

Abstract: Traditional probability statistics theory is impossible to obtain failure lifetime data by accelerated test for expensive and complex systems or equipments for real-time work. Due to the variety of system failure modes and the randomness of system deterioration process and the fuzziness of system maintenance threshold, it is difficult to estimate the random deterioration process of a complex repairable system by single parameter. In order to describe system performance deterioration more subjectly, it proposes generalized proportional intensity model(GPIM). considering the effects of various covariates such as performance parameters, environment stress, failure types and maintenance history simultaneously. This method provides a new method to solve the maintenance decision-making problem of complex repairable system. CF6-80C2A5 aero-engine is illustrated as an example for case study to indicate the obvious practical value by the method proposed herein.