Publication
Development and application of optical fiber-based sensors for structural health monitoring of wind turbine blades
| Summary: | In the present work, conducted as part of an internship at Siemens Gamesa Renewable Energy, optical fiber accelerometers based on Bragg gratings were developed with the aim of structural health monitoring of wind turbine blades. The dissertation begins with a description of the context of global and local energy consumption, as well as the motivation for this dissertation. In addition to a theoretical introduction to fiber optic Bragg gratings and the main methods used for their inscription, the state of the art regarding different geometries, sensitivities, and characteristics (such as the presence of metallic elements) of optical fiber sensor-based accelerometers is presented. An approach to optical accelerometers available on the market is also presented, highlighting some key parameters that should be considered in the process of selecting a device. The typical structure of wind turbine blades is described, as well as some fundamental concepts, such as the types of damage typically observed, which allow for the subsequent analysis of the tests carried out. Due to the wide versatility of geographical locations where a wind turbine can be installed and the consequent environmental variability, it is important to understand the response of the sensors used to these environmental parameters, so that these effects can be compensated. Thus, through the characterizations performed, a self-compensated temperature sensitivity of (3.6 ± 0.6) pm/ºC and a self-compensated relative humidity sensitivity of (1.6 ± 0.1) pm/%RH were obtained, confirming that these parameters can be neglected. For an operating frequency range of 0 to 30 Hz, an acceleration sensitivity of (77 ± 2) pm/G was achieved. To evaluate and verify the sensor's performance in a real context, tests were conducted in a controlled environment with a composite sample of identical characteristics to a blade, where its free-end length was varied to obtain different frequencies within the desired measurement range. Other parameters, such as the sensor's position or the excitation method, were also tested. In the final phase, tests were conducted on an SG170 blade where an intervention for repairs was carried out. As a result, a discrepancy was observed between the simulated results and the experimental results obtained, which was attributed to the damages and repairs present in the blade. |
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| Main Authors: | Magalhães, Yannis João Maia |
| Subject: | Accelerometers Fiber bragg gratings Structural health monitoring Optical fiber sensors Wind turbine blades. |
| Year: | 2024 |
| Country: | Portugal |
| Document type: | master thesis |
| Access type: | embargoed access |
| Associated institution: | Universidade de Aveiro |
| Language: | English |
| Origin: | RIA - Repositório Institucional da Universidade de Aveiro |
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