1 汇报安排

题 目：参加 COMADEM 2015+X CORENDE国际会议总结报告会

时 间：2015年12月9日（周三）晚上19：00–21：00

地 点：交大曲江校区西五楼北楼A228会议室

报 告 人：

博1115班 牛蔺楷 学号：4111001034 指导教师：何正嘉 教授 曹宏瑞 副教授

博1321班 张明泉 学号：4113001105 指导教师：訾艳阳 教授

博1320班 陆建涛 学号：4113001080 指导教师：何正嘉 教授 成 玮 副教授

博1502班 潘 骏 学号：4115001030 指导教师：訾艳阳 教授 陈景龙 讲师

2 参加国际会议信息

会议名称：COMADEM 2015+X CORENDE

会议日期：1-4 December, 2015

会议地点：Buenos Aires, Argentina

会议简介：The Congress intends to invite and integrate people involved in this study area in an open forum. The purpose of the congress is to encourage and facilitate exchange of information and experiences from all regions of the world. COMADEM is the opportunity to get in touch with technologies that continuously improve and enhance the quality, reliability, safety, availability, maintainability and performance of all assets (both physical and human) for as long as possible and to derive maximum benefits with minimum risk. CORENDE is a forum to discuss the improvements in the technologies used in the evaluation of components, systems and structures: non-destructive testing, personnel certification, standards, welding inspection, maintenance and structural testing. The program will provide an unrivalled opportunity to network with representatives from globally significant research centers, industry leading companies, government organizations, professional bodies and Universities.

3 参会论文信息

Tittle: Dynamic modeling and vibration simulation for double-row tapered roller bearings with localized surface defects

Author: Linkai Niu, Hongrui Cao, and Zhengjia He

Abstract- A dynamic model without static constraints is provided for double-row tapered roller bearings (DRTRBs) with localized surface defects. In this model, each bearing component has six degrees of freedom (DOFs) to completely describe its dynamic characteristics. Four types of interactions, i.e. roller-cup, roller-cone, roller-flange, and roller-cage pocket are considered in this model. Relative slip velocities, friction effects and localized surface defects are also considered. The obtained dynamic equations are solved numerically using the fourth order Runge-Kutta-Fehlberg scheme with step-changing criterion. Vibration responses of the DRTRB with localized surface defects are analyzed in both time domain and frequency domain. Effects of defect sizes, defect types on dynamic characteristics of the bearing are studied parametrically. Numerical results obtained from the current simulation are validated with respect to prior researchers.

Tittle: Fault recognition of marine diesel engines via cyclic polar map method

Author: Mingquan Zhang, Yanyang Zi, Jinglong Chen, Yu Wang, and Yiqing Li

Abstract- Determining the reliability of a diesel engine with efficient and robust fault diagnosis techniques is important to ensure that the engine stays in optimal operating condition and minimize the probability of failure. However, most current techniques for this purpose rely on the specification of threshold levels and heuristic knowledge to assign states as non-faulty or faulty, making them difficult to be widely adopted in practice. This article introduces a cyclic polar map (CPM) method to diagnose the abnormal combustion using the information contained in the instantaneous crankshaft speed variations. A new time domain evaluating indicator, related to the power contribution of each cylinder, is proposed to generate polar map (PM). The CPM, as the expression form of cycle-to-cycle variation in PM, is used to show the non-uniformities in operation. Moreover, this method only processes the data during one engine cycle, which makes it more suitable for real-time diagnosis. To validate its effectiveness, three typical experimental studies on a 16-cylinder marine diesel engine at three different loads of 25%, 50% and 75% are discussed in this paper. The results show that distortion degree of CPM can well reflect the fault deterioration trend and the fault cylinder position.

Tittle: Adaptive step size algorithm for online blind source separation

Author: Jiantao Lu, Wei Cheng, Yanyang Zi, and Zhengjia He

Abstract- The traditional blind source separation (BSS) algorithms with fixed step size have the disadvantage that cannot well balance the convergence rate and the steady-state error. A novel adaptive step size algorithm for online BSS is proposed to solve this problem, which can speed up the convergence rate, and reduce the steady state error of the adaptive BSS algorithm. A separation indicator that indicates the separation degree is constructed by the convergence condition of the EASI algorithm, and the indicator is applied to improve the step size. To weaken the error effects at the initial stage, the forgetting factor is used to online update the separation indicator. Finally, a nonlinear monotone increasing function is proposed, which implements the one-to-one mapping between the separation indicator and the step size. Compared with the fixed step size natural gradient algorithm, the fixed step size EASI algorithm, the exponential decay step size algorithm and the adaptive step size algorithm with weighted orthogonalization, the proposed algorithm has faster convergence rate, smaller steady state error and better robustness. This research can benefit for the vibration & acoustical source separation and identification, and provide pure source information for machinery condition monitoring and fault diagnosis.

Tittle: Ship-borne Satellite Antenna Bearing Fault Diagnosis using Enhanced Empirical Wavelet Transform via Data-driven Adaptive Fourier Spectrum Segment

Author: Jun Pan, Yanyang Zi, Jinglong Chen, and Shuilong He

Abstract- An unexpected bearing fault of the ship-borne satellite antenna will result in unacceptable downtime of the system as well as failure of communication task. However, bearing fault diagnosis using vibration signals still is a challenging task because of the system complexity and the multi-modulation feature in the vibration signals. As a novel signal processing method, Empirical Wavelet Transform (EWT) is used to extract inherent modulation information by decomposing signal into mono-components under an orthogonal basis. But the pre-defined segment way of Fourier spectrum without dependence on analyzed signals would result in inaccurate mono-component decomposition. In this paper, the enhanced EWT (EEWT) method with data-driven adaptive Fourier spectrum segment is proposed for ship-borne satellite antenna bearing fault diagnosis. First, inner product is calculated between the Fourier spectrum of analyzed signal and Gaussian function for scale representation. Then, adaptive spectrum segment is achieved by detecting local minima of the scale representation. Finally, empirical modes can be obtained by adaptively merging mono-components based on their envelope spectrum similarity. The adaptively extracted empirical modes are analyzed for bearing fault diagnosis. The application case is used to verify the effectiveness of the proposed method and the results show its outstanding performance.

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