Publicação
Optical fiber sensors for cure and structural health monitoring of composites for wind turbine blades
| Resumo: | In this work, a fiber optic sensor configuration is proposed for integration into composites, intended for application in wind turbine blades. The proposed sensor consists of a Fabry-Perot interferometer (FPI) sensor in series with a fiber Bragg grating (FBG) sensor to monitor the curing and structural health of composites. The FPI sensors were manufactured with different cavity lengths and using different capillary tubes to study the influence of these variables on their spectral response. All sensors were characterized for the parameters of interest, temperature, and strain. The FBG sensors exhibited sensitivity values between (9.76 ± 0.05) pm/°C and (10.94 ± 0.01) pm/°C for temperature, and between (1.19 ± 0.02) pm/µε and (1.30 ± 0.02) pm/µε for strain, which is in accordance with literature. The FPI sensors showed negligible sensitivity values for temperature, in general below 1 pm/°C. Regarding strain, a trend was observed that relates increasing sensitivity to decreasing cavity size and the use of capillary tubes with larger internal diameters. Four of the fabricated sensors were embedded in a six-layer glass fiber composite. The sensors successfully monitored the temperature and strain profile during the curing process. In addition, the temperature and tensile tests to which the composite was subjected demonstrated the functionality of these sensors after embedment Later, nine sensors were fabricated and embedded in a second composite with thirty layers. The sensors were placed at three different levels inside the composite to allow monitoring at various depths. The results of the curing process showed that the temperature reached higher values in the central area of the composite and that strain dominates in the center of the lower layers. A sensor response to the temperature test similar to that of the sensors embedded in the first composite was obtained. On the other hand, the four-point flexural tests proved that these sensors can determine the direction of the curvature of the structure. The proposed sensors proved to be a viable solution for cure monitoring and structural analysis of composites and are a starting point in the real time monitoring of wind turbine blades. |
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| Autores principais: | Ferreira, Laura Gomes Moleiro de Campos |
| Assunto: | Wind turbine Optical fiber Composite Cure Structural health |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | In this work, a fiber optic sensor configuration is proposed for integration into composites, intended for application in wind turbine blades. The proposed sensor consists of a Fabry-Perot interferometer (FPI) sensor in series with a fiber Bragg grating (FBG) sensor to monitor the curing and structural health of composites. The FPI sensors were manufactured with different cavity lengths and using different capillary tubes to study the influence of these variables on their spectral response. All sensors were characterized for the parameters of interest, temperature, and strain. The FBG sensors exhibited sensitivity values between (9.76 ± 0.05) pm/°C and (10.94 ± 0.01) pm/°C for temperature, and between (1.19 ± 0.02) pm/µε and (1.30 ± 0.02) pm/µε for strain, which is in accordance with literature. The FPI sensors showed negligible sensitivity values for temperature, in general below 1 pm/°C. Regarding strain, a trend was observed that relates increasing sensitivity to decreasing cavity size and the use of capillary tubes with larger internal diameters. Four of the fabricated sensors were embedded in a six-layer glass fiber composite. The sensors successfully monitored the temperature and strain profile during the curing process. In addition, the temperature and tensile tests to which the composite was subjected demonstrated the functionality of these sensors after embedment Later, nine sensors were fabricated and embedded in a second composite with thirty layers. The sensors were placed at three different levels inside the composite to allow monitoring at various depths. The results of the curing process showed that the temperature reached higher values in the central area of the composite and that strain dominates in the center of the lower layers. A sensor response to the temperature test similar to that of the sensors embedded in the first composite was obtained. On the other hand, the four-point flexural tests proved that these sensors can determine the direction of the curvature of the structure. The proposed sensors proved to be a viable solution for cure monitoring and structural analysis of composites and are a starting point in the real time monitoring of wind turbine blades. |
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