This introduction begins with a brief history of SHM technology development. Recent research has begun to recognise that a productive approach to the Structural Health Monitoring (SHM) problem is to regard it as one of statistical pattern recognition (SPR); a paradigm addressing the problem in such a way is described in detail herein as it forms the basis for the organisation of this book. In the process of providing the historical overview and summarising the SPR paradigm, the subsequent chapters in this book are cited in an effort to show how they fit into this overview of SHM. In the conclusions are stated a number of technical challenges that the authors believe must be addressed if SHM is to gain wider acceptance.

An introduction to structural health monitoring

This book focuses on structural health monitoring in the context of machine learning. The authors review the technical literature and include case studies. Chapters include: operational evaluation, sensing and data acquisition, introduction to probability and statistics, machine learning and statistical pattern recognition, and data prognosis.

Structural Health Monitoring: A Machine Learning Perspective

https://www.win.tue.nl/~sjoerdr/papers/boek.pdf

An introduction to acoustics

Offshore Wind has become the most profitable renewable energy source due to the remarkable development it has experienced in Europe over the last decade. In this paper, a review of Structural Health Monitoring Systems (SHMS) for offshore wind turbines (OWT) has been carried out considering the topic as a Statistical Pattern Recognition problem. Therefore, each one of the stages of this paradigm has been reviewed focusing on OWT application. These stages are: Operational Evaluation; Data Acquisition, Normalization and Cleansing; Feature Extraction and Information Condensation; and Statistical Model Development. It is expected that optimizing each stage, SHMS can contribute to the development of efficient Condition-Based Maintenance Strategies. Optimizing this strategy will help reduce labor costs of OWTs׳ inspection, avoid unnecessary maintenance, identify design weaknesses before failure, improve the availability of power production while preventing wind turbines׳ overloading, therefore, maximizing the investments׳ return. In the forthcoming years, a growing interest in SHM technologies for OWT is expected, enhancing the potential of offshore wind farm deployments further offshore. Increasing efficiency in operational management will contribute towards achieving UK׳s 2020 and 2050 targets, through ultimately reducing the Levelised Cost of Energy (LCOE).

Structural health monitoring of offshore wind turbines: A review through the Statistical Pattern Recognition Paradigm

Cracks in shafts have long been identified as factors limiting the safe and reliable operation of turbomachines. They can sometimes result in catastrophic failure of equipment (rotor bursts) and, more often, in costly process upsets, repairs and premature scrapping and replacement of equipment. Cracked shafts still pose a significant and real threat to equipment in spite of the great advances made in the areas of metallurgy, manufacturing and design. In the past two decades, much research and many resources have gone into developing various on-line and off-line diagnostic techniques to effectively detect cracks before they cause serious damage. Because of the enormous amount of ongoing research in this area (more than 500 technical papers have been published in English alone in the past 30 years), there is a real need to periodically condense and summarize the information. This paper reviews literature on cracked shaft detection and diagnostics published after 1990.

Cracked shaft detection and diagnostics: A literature review

Examining the fundamentals of machinery diagnostics for those working with rotating machinery, this volume prepares engineers, researchers, and students for the future of rotor dynamics and bearing technology, especially pressurized bearings. Demystifying important concepts in the diagnosis of machinery malfunction, it serves as an essential reference for anyone who works with rotating machinery, from operator to manager and from design engineer to machinery diagnostician. The book features hundreds of full color illustration explaining key concepts, numerous detailed case histories demonstrating actual solutions to machinery problems, and a comprehensive glossary of diagnostic terms.

Fundamentals of Rotating Machinery Diagnostics

Frequency-swept rotating input perturbation techniques and identification of the fluid force models in rotor/bearing/seal systems and fluid handling machines

Rotor/seal full annular rub, including synchronous (forward) and reverse (backward) precessions, has been investigated both experimentally and analytically. Of particular interest is the finding of reverse precessional full annular rub (dry whip) that occurs repeatedly in small clearance cases without any outside disturbance. The experimental results include rub triggering mechanism, mass unbalance, and rotative speed effects. A simplified mathematical model is used to interpret experimental results. Nonlinear solutions for both synchronous and reverse precessions are obtained along with instability zones. Mass unbalance effect on shifting from synchronous response to reverse rub and destabilizing factors such as dry friction, rotor damping, and seal stiffness, are discussed.

Rotor/Seal Experimental and Analytical Study on Full Annular Rub

Active Controlled Hydrostatic Bearings for a New Generation of Machines

This paper presents the results of recent experimental studies on rotor/seal full annular rub, including forward and reverse precession. It was found that reverse precessional full annular rub (dry whip) could occur repeatedly in small clearance cases without any outside disturbance. The rotor rubbed against the seal with almost constant amplitude and frequency, which was higher than the natural frequency of the original rotor system and lower than of that of the coupled rotor/seal system. Once generated, the reverse precessional rub could be sustained over the whole speed range as long as slippage was maintained. Radius-to-clearance ratio varied from 10 to 40. The experimental studies include forward rub jump phenomena, reverse rub triggering mechanism, and effects of mass unbalance, surface lubrication, shaft speed, and seal stiffness. The results of both forward and reverse precession are discussed in detail, with emphasis on the reverse and the transition from the forward to the reverse.

/pdf/full-annular-rub-in-mechanical-seals-part-i-experimental-2t6bw69hnu.pdf

Donald E. Bently

Papers

Fundamentals of Rotating Machinery Diagnostics

Frequency-swept rotating input perturbation techniques and identification of the fluid force models in rotor/bearing/seal systems and fluid handling machines

Rotor/Seal Experimental and Analytical Study on Full Annular Rub

Active Controlled Hydrostatic Bearings for a New Generation of Machines

Full Annular Rub in Mechanical Seals, Part I: Experimental Results