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BL
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| Record Number
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889289
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| Main Entry
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Li, Dan
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| Title & Author
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Rail crack monitoring using acoustic emission technique /\ Dan Li.
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| Publication Statement
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Singapore :: Springer,, 2018.
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| Series Statement
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Springer theses,
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| Page. NO
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1 online resource (xxviii, 136 pages) :: illustrations (some color)
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| ISBN
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9789811083488
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: 9811083487
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9789811083471
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9811083479
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| Notes
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"Doctoral thesis accepted by the National University of Singapore, Singapore."
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| Bibliographies/Indexes
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Includes bibliographical references.
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| Contents
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Intro; Supervisor's Foreword; Parts of this thesis have been published in the following journal articles:Li, D. *, Kuang, K.S.C., Koh, C.G. (2017). Rail crack monitoring based on Tsallis synchrosqueezed wavelet entropy of acoustic emission signals: a field study. Structural Health Monitoring. Prepublished online December 4, 2017, DOI: 10.1177/1475921717742339. Li, D., Kuang, K.S.C. *, Koh, C.G. (2017). Fatigue crack sizing in rail steel using crack closure-induced acoustic emission waves. Measurement Science and Technol; Acknowledgements; Contents; Abbreviations; Nomenclature.
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2.3.3 Relevant Applications of AE Technique2.4 State-of-Art of Rail Condition Monitoring Using AE; References; 3 Propagation Features and Source Location; 3.1 Introduction; 3.2 Experimental Procedure; 3.2.1 Pencil Lead Break (PLB); 3.2.2 Field PLB Test; 3.2.3 Field Train Pass-by Test; 3.2.4 AE Data Acquisition; 3.3 Time-Frequency Representation of AE Waves; 3.3.1 Continuous Wavelet Transform (CWT); 3.3.2 Optimal Mother Wavelet Selection; 3.3.3 Time-Frequency Characteristics of AE Waves; 3.4 Propagation Features of AE Waves; 3.4.1 Theory of Ultrasonic Propagation.
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3.4.2 Attenuation of AE Waves in Rail Head3.4.3 Dispersion of AE Waves in Rail Head; 3.5 Source Location Methods; 3.5.1 Time-of-Arrival (TOA) Method; 3.5.2 Wavelet Transform-Based Modal Analysis Location (WTMAL) Method; 3.6 Hilbert Transform-Based Noise Cancellation Method; 3.7 Results and Discussion; 3.7.1 Influence of Operational Noise on Crack Detection; 3.7.2 Source Location Without Noise Using TOA Method; 3.7.3 Source Location Without Noise Using WTMAL Method; 3.7.4 Source Location with Noise Using WTMAL Method; 3.8 Concluding Remarks; References; 4 Sizing of Fatigue Cracks.
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4.1 Introduction4.2 Experimental Procedure; 4.2.1 Rail Steel Specimens; 4.2.2 Fatigue Tests; 4.2.3 AE Data Acquisition; 4.2.4 Crack Length Calculation; 4.2.5 Crack Surface Observation; 4.3 AE Wave Classification; 4.3.1 Wavelet Power (WP)-Based Classification Index; 4.3.2 Threshold Determination for the Classification Index; 4.3.3 Frequency Bands Selection for the Classification Index; 4.4 Fatigue Crack Sizing Methods; 4.4.1 Traditional Method Based on CP-Induced AE Waves; 4.4.2 Novel Method Based on CC-Induced AE Waves; 4.4.3 Comparison of Crack Sizing Methods; 4.5 Results and Discussion.
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List of FiguresList of Tables; Summary; 1 Introduction; 1.1 Background; 1.2 Objectives and Scope of Research; 1.3 Research Significance; 1.4 Thesis Outline; References; 2 Literature Review; 2.1 Common Defects of Rail Track; 2.1.1 Surface Cracks; 2.1.2 Internal Cracks; 2.2 Current Rail Monitoring Techniques; 2.2.1 Acceleration-Based Technique; 2.2.2 Automated Visual Technique; 2.2.3 Ultrasonic Techniques; 2.2.4 Electromagnetic Techniques; 2.2.5 Magnetic Induction Technique; 2.3 AE Technique and Its Applications; 2.3.1 Introduction to AE Technique; 2.3.2 Characterization of AE Waves.
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| Abstract
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This thesis provides an innovative strategy for rail crack monitoring using the acoustic emission (AE) technique. The field study presented is a significant improvement on laboratory studies in the literature in terms of complex rail profile and crack conditions as well as high operational noise. AE waves induced by crack propagation, crack closure, wheel-rail impact and operational noise were obtained through a series of laboratory and field tests, and analyzed by wavelet transform (WT) and synchrosqueezed wavelet transform (SWT). A wavelet power-based index and the enhanced SWT scalogram were sequentially proposed to classify AE waves induced by different mechanisms according to their energy distributions in the time-frequency domain. A novel crack sizing method taking advantage of crack closure-induced AE waves was developed based on fatigue tests in the laboratory. The propagation characteristics of AE waves in the rail were investigated, and Tsallis synchrosqueezed wavelet entropy (TSWE) with time was finally brought forward to detect and locate rail cracks in the field. The proposed strategy for detection, location and sizing of rail cracks helps to ensure the safe and smooth operation of the railway system. This thesis is of interest to graduate students, researchers and practitioners in the area of structural health monitoring.
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| Subject
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Acoustic emission testing.
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| Subject
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Railroad tracks-- Testing.
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Acoustic emission testing.
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Railroad tracks-- Testing.
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| Subject
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TECHNOLOGY ENGINEERING-- Engineering (General)
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| Dewey Classification
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625.1/5
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| LC Classification
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TF537
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