Acquisition and processing of new data sources for improved condition monitoring of mechanical systems

190 p.Este trabajo está centrado en el desarrollo de nuevas formas de monitorización en línea del estado de salud de sistemas mecánicos mediante tecnologías poco utilizadas hasta ahora en este campo. En particular, se han investigado el uso de la monitorización de la viscosidad del aceite lubricante y la tecnología de análisis de las características de la corriente que alimenta el motor para obtener conocimiento sobre el estado de las cajas de engranajes. Por un lado, se presenta una nueva solución basada en materiales magnetoelásticos para la monitorización de la viscosidad del aceite lubricante. Por el otro, el análisis de la corriente alimentación del motor (MCSA por sus siglas en inglés) se presenta como alternativa de los acelerómetros tradicionales para la monitorización de anomalías mecánicas.En particular, se ha desarrollado un sensor magnetoelástico de viscosidad cinemática para mediciones en línea. La principal ventaja del sensor propuesto es su capacidad de medir en una amplia gama de valores de viscosidad (desde 32 cSt hasta 320 cSt). No se conoce ningún otro sensor equivalente comercialmente disponible con un rango similar.Con respecto al análisis de las características de la corriente de alimentación del motor (MCSA), el objetivo de la Tesis es poder diseñar un sistema para monitorizar una caja de engranajes en funcionamiento normal. En este sentido, se ha abordado el análisis de transitorios de velocidad, manteniendo la carga fija. Se ha utilizado un banco de pruebas de cajas de engranajes para reproducir diferentes fallos y adquirir datos en diferentes condiciones de operación

Acquisition and processing of new data sources for improved condition monitoring of mechanical systems

190 p.Este trabajo está centrado en el desarrollo de nuevas formas de monitorización en línea del estado de salud de sistemas mecánicos mediante tecnologías poco utilizadas hasta ahora en este campo. En particular, se han investigado el uso de la monitorización de la viscosidad del aceite lubricante y la tecnología de análisis de las características de la corriente que alimenta el motor para obtener conocimiento sobre el estado de las cajas de engranajes. Por un lado, se presenta una nueva solución basada en materiales magnetoelásticos para la monitorización de la viscosidad del aceite lubricante. Por el otro, el análisis de la corriente alimentación del motor (MCSA por sus siglas en inglés) se presenta como alternativa de los acelerómetros tradicionales para la monitorización de anomalías mecánicas.En particular, se ha desarrollado un sensor magnetoelástico de viscosidad cinemática para mediciones en línea. La principal ventaja del sensor propuesto es su capacidad de medir en una amplia gama de valores de viscosidad (desde 32 cSt hasta 320 cSt). No se conoce ningún otro sensor equivalente comercialmente disponible con un rango similar.Con respecto al análisis de las características de la corriente de alimentación del motor (MCSA), el objetivo de la Tesis es poder diseñar un sistema para monitorizar una caja de engranajes en funcionamiento normal. En este sentido, se ha abordado el análisis de transitorios de velocidad, manteniendo la carga fija. Se ha utilizado un banco de pruebas de cajas de engranajes para reproducir diferentes fallos y adquirir datos en diferentes condiciones de operación

Damage identification in structural health monitoring: a brief review from its implementation to the Use of data-driven applications

The damage identification process provides relevant information about the current state of a structure under inspection, and it can be approached from two different points of view. The first approach uses data-driven algorithms, which are usually associated with the collection of data using sensors. Data are subsequently processed and analyzed. The second approach uses models to analyze information about the structure. In the latter case, the overall performance of the approach is associated with the accuracy of the model and the information that is used to define it. Although both approaches are widely used, data-driven algorithms are preferred in most cases because they afford the ability to analyze data acquired from sensors and to provide a real-time solution for decision making; however, these approaches involve high-performance processors due to the high computational cost. As a contribution to the researchers working with data-driven algorithms and applications, this work presents a brief review of data-driven algorithms for damage identification in structural health-monitoring applications. This review covers damage detection, localization, classification, extension, and prognosis, as well as the development of smart structures. The literature is systematically reviewed according to the natural steps of a structural health-monitoring system. This review also includes information on the types of sensors used as well as on the development of data-driven algorithms for damage identification.Peer ReviewedPostprint (published version

NASA SBIR abstracts of 1991 phase 1 projects

The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included

Development and Experimentation of Magnetostrictive Sensors for Inspection and Monitoring of Piping Systems

Nondestructive Evaluation – NDE, is an important aspect of the integrity management of industrial plants, where pipe systems are the dominant component. During the last decade Ultrasonic Guided Waves (UGW), have started to be used as a useful instrument for on-stream long range inspection of pipes. Various procedures and systems have been proposed for the generation and detection of UGW. Presently, they are based on piezoelectric (PZT) or magnetostrictive (MT) transducers or electromagnetic acoustic transducers (EMAT). It is generally known that PZT based systems have elevated diagnostic capacities due to their high transduction efficiency. However, the elevated costs of installation of such devices make their use for long-term monitoring of piping systems quite improbable. On the other hand, the MT based systems have the advantage of the reduced costs of the composing materials, simplicity of attaching it to the pipe wall and flexibility regarding the diameters of the pipes that can be inspected. Still, its single-element configuration limits the capacity to characterize the detected discontinuities in terms of geometry, thus being unable to distinguish between possible flaws from symmetrical features, normally located on pipes, like welds or flanges. Furthermore, its reduced capability to geometrically characterize flaws makes the classification of their severity particularly difficult. The improvement of the diagnostic capacity of MT based systems in order to make practically possible and economically convenient its use in monitoring applications is the main purpose of this thesis. In this dissertation multiple laboratory and field experiments are described and the magnetostrictive technology is evaluated. Furthermore, a new magnetostrictive transducer for UGW acquisition is presented. It allows step-by-step data acquisition around the pipe circumference revealing important information on the geometry and circumferential position of flaws. The new sensor was validated by computer simulations as well as further laboratory and field tests. The resulting data was used as input for various digital signal processing techniques to describe geometrically the features detected in the acquired signal. The final results outline the potential of MT based long-range inspection to reach also a good sensitivity and a good defect sizing and classification with respect to conventional techniques, making it an important candidate for monitoring activities for the integrity management of industrial plants

NASA SBIR abstracts of 1992, phase 1 projects

The objectives of 346 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1992 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 346, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1992 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included