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Individual aircraft life monitoring： An engineering approach for fatigue damage evaluation

Chinese Journal of Aeronautics 2018年第4期31卷 727-739页

作者： Rui JIAO Xiaofan HE Yuhai LI School of Aeronautic Science and Engineering Beihang University Beijing 100083 China A viation Industry Corporation of China Beijng 100022 China

Individual aircraft life monitoring is required to ensure safety and economy of aircraft structure, and fatigue damage evaluation based on collected operational data of aircraft is an integral part of it. To improve the accuracy and facilitate the application, this paper proposes an engineering approach to evaluate fatigue damage and predict fatigue life for critical structures in fatigue monitoring. In this approach, traditional nominal stress method is applied to back calculate the S-N curve parameters of the realistic structure details based on full-scale fatigue test data. Then the S-N curve and Miner＇s rule are adopted in damage estimation and fatigue life analysis for critical locations under individual load spectra. The relationship between relative small crack length and fatigue life can also be predicted with this approach. Specimens of 7 B04-T74 aluminum alloy and TA15 M titanium alloy are fatigue tested under two types of load spectra, and there is a good agreement between the experimental results and analysis results. Furthermore, the issue concerning scatter factor in individual aircraft damage estimation is also discussed.

关键词： fatigue damage fatigue monitoring fatigue test Scatter factor S-N curve

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DRIVER’S ALERTNESS LEVEL IDENTIFY METHOD BASED ON COMPUTER VISION

DRIVER’S ALERTNESS LEVEL IDENTIFY METHOD BASED ON COMPUTER ...

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第一届交通运输工程国际学术会议

作者： YANG Ying1 , SHENG Jing1, and ZHOU Wei1 Vehicle Institute, School of Mechanical Engineering and Automation, Northeastern University, P.O. Box 319, Shenyang 110004 China

This paper adopts CCD video fixed in a cab monitoring driver to recognize whether he/she is tired. The drivers’ alertness level is detected by monitor both their eyes and mouths states. This paper puts forward a new method to locate the driver’s face feature points by using pigment distributing. First, according to the character that lip is red, detecting and searching the red region in order to separate the lip from other parts, then combine the edge extract and red pigment method to get the shape of driver’s lip. Then use the approaching method to locating the lip’s feature points. The eye’s position is fixed according to human face figure and its feature points are obtained by using the same method with lip. Put all the feature points into BP networks, adopts area matching arithmetic to recognize driver’s alertness level, fatigue monitor system can recognize that the driver is in decreased alertness state when he/she yawns more times than normal, then the system gives off alarm signal, and awakes the driver;the system can also recognize that the driver is in drowsy state when driver’s eyes blink frequency is lower than standard value, then it gives sharp alarm signal to wake the driver up. It has the characteristic of real time, accuracy. The recognized accuracy rate reaches to 94.3%. This driver fatigue monitoring system has significant effect to reduce traffic accident.

关键词： driver alertness level fatigue monitoring vision

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