Xie H.,Beihang University |
Shi J.,Beihang University |
Lu W.,Aircraft Maintenance and Engineering Corporation |
Cui W.,China Academy of Launch Vehicle Technology
Proceedings of 2016 Prognostics and System Health Management Conference, PHM-Chengdu 2016 | Year: 2016
Bayesian network is the main research method in the field of artificial intelligence for uncertainty problem representation and processing of and health grading evaluation is one of the important technology in health management. Through the analysis of different models and study methods of Bayesian theory, combining the characteristics of the three-state dividing of system, the three states of dynamic Bayesian network health evaluation method is put forward, which calculates the dynamic Bayesian network using the hidden Markov model. Then EM algorithm and CRLA algorithm for dynamic Bayesian networks parameter learning are studied. Finally, based on Pspice simulation software and the DBN software toolbox of Matlab, the three-stage amplifier circuit Bayesian evaluation model of the three health states is built, and the corresponding application instructions and results are obtained. Thus the correctness and feasibility of the related methods put forward in this paper are verified. © 2016 IEEE.
Cao H.,Civil Aviation University of China |
Wu Z.,Civil Aviation University of China |
Qu C.,Civil Aviation University of China |
Kang L.,Aircraft Maintenance and Engineering Corporation
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2015
Based on CBM strategy, the life on wing prediction of aeroengine was made herein, aiming at providing airlines with a scientific and reasonable basis for the engine's plans of removal. Firstly, according to the aeroengine's historical data of removal, a mathematical model of the maintenance decision-making control limit was established. And the establishment of this model was based on the proportional hazards-proportional odds model. Then using time series prediction method based on least squares support vector machine, and combined with the condition trend prediction of engine, life on wing of engine was predicted. Finally, in the case study of a concrete instance, the method was proved to be effective and to have a high practical value. ©, 2015, China Mechanical Engineering Magazine Office. All right reserved.
Su J.,Civil Aviation University of China |
Ma M.,Civil Aviation University of China |
Wang T.,Aircraft Maintenance and Engineering Corporation |
Guo X.,Aircraft Maintenance and Engineering Corporation |
And 2 more authors.
Chinese Journal of Aeronautics | Year: 2015
Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum coupons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film and initiates corrosion. The galvanic corrosion between the metal and the adjacent carbon particles accelerates the corrosive process. Furthermore, the black carbon favors the moisture uptake, and gives the dissolved oxygen greater chance to migrate through the fouling layer and form a continuous diffusive path. The corrosion rate decreasing over time is conformed to electrochemistry measurements and can be verified by Faraday's law. The EIS results indicate that the mechanism of corrosion can be interpreted by the pitting corrosion evolution mechanism, and that pitting was observed on the coupons by SEM after corrosive exposure. © 2015 The Authors.
Wang F.,Aircraft Maintenance and Engineering Corporation |
Cui D.,Science and Technology Committee
29th Congress of the International Council of the Aeronautical Sciences, ICAS 2014 | Year: 2014
The paper presents a project simplified theory and a method of calculating postbuckling loading capacity of composite stiffened panels based on the basic mechanics characters of composite materials, combining FEM theory and engineering experience. Composite Jstiffened panels are taken as an example to illustrate thinking and computational formula of post-buckling analysis from the perspective of engineering. The validity and effectiveness of the method are demonstrated with the experiment. It is shown the analysis method of stability loading capability can solve the geometric non-linear problem of composite stiffened panel structure load capability and keep high accuracy in the aero-structure design.