Browsing by Author "Walker, Ryan"

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    Localising imbalance faults in rotating machinery
    (Cranfield University, 2013-06) Walker, Ryan; Perinpanayagam, Sureshkumar
    This thesis presents a novel method of locating imbalance faults in rotating machinery through the study of bearing nonlinearities. Localisation in this work is presented as determining which discs/segments of a complex machine are affected with an imbalance fault. The novel method enables accurate localisation to be achieved using a single accelerometer, and is valid for both sub and super-critical machine operations in the presence of misalignment and rub faults. The development of the novel system for imbalance localisation has been driven by the desire for improved maintenance procedures, along with the increased requirement for Integrated Vehicle Health Management (IVHM) systems for rotating machinery in industry. Imbalance faults are of particular interest to aircraft engine manufacturers such as Rolls Royce plc, where such faults still result in undesired downtime of machinery. Existing methods of imbalance localisation have yet to see widespread implementation in IVHM and Engine Health Monitoring (EHM) systems, providing the motivation for undertaking this project. The imbalance localisation system described has been developed primarily for a lab-based Machine Fault Simulator (MFS), with validation and verification performed on two additional test rigs. Physics based simulations have been used in order to develop and validate the system. An Artificial Neural Network (ANN) has been applied for the purposes of reasoning, using nonlinear features in the frequency domain originating from bearing nonlinearities. The system has been widely tested in a range of situations, including in the presence of misalignment and rub faults and on a full scale aircraft engine model. The novel system for imbalance localisation has been used as the basis for a methodology aimed at localising common faults in future IVHM systems, with the aim of communicating the results and findings of this research for the benefit of future research. The works contained herein therefore contribute to scientific knowledge in the field of IVHM for rotating machinery.
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    Physics-Based Simulation for Health Management of Rotating Machinery
    (2011-06-22T00:00:00Z) Walker, Ryan; Perinpanayagam, Suresh; Jennions, Ian K.
    Data-driven techniques for diagnosing faults in rotating machinery have a long history. Such approaches undoubtedly have their strengths and much research is still being performed in this area - recently into gearbox and bearing faults in particular. However, with the increasing power and sophistication of simulation tools, new methods for diagnosis, localization and prognosis of faults are rapidly being researched. This paper outlines current developments in modeling and simulation for rotating machinery health management and discusses the potential for such technologies to move from the realm of research into live systems. Comparisons and synergies with traditional data driven methods are made and it is concluded that simulation-driven techniques have much potential for next generation PHM systems.