Implementation and appraisal of an in-fibre Bragg grating quasi-distributed health and usage monitoring system with applications to advanced materials
| dc.contributor.advisor | Tatam, Ralph P. | |
| dc.contributor.author | O'Dwyer, Martin Joseph | |
| dc.date.accessioned | 2023-05-04T13:47:30Z | |
| dc.date.available | 2023-05-04T13:47:30Z | |
| dc.date.issued | 2000-07 | |
| dc.description.abstract | A portable and compact demodulation system was constructed and calibrated. It was found that the best performance could be achieved using the peak detection algorithm written in a LabView™ program. A resolution of 0.96±0.07pe was achieved over a range of 30,000ps. This system was used to characterise IFBG sensors. Firstly the temperature effects on the strain response of a number of IFBGs written into a number of differing fibre types was investigated. A model was derived to gauge if the observed changes were consistent with the accepted theory of Bragg gratings. It was found that the strain response changed on average by 0.21 ^.O Sfm ps'1 °C 1. The obtained results were in agreement with the predicted result simulated using the model. Secondly, a spliced pair IFBG configuration was examined to assess its effectiveness as a temperature independent strain sensor. From the results that were obtained it was concluded that this sensor configuration can usefully measure applied temperature and strain, though errors in the solution matrix led to significant errors in the final measurements. For the process monitoring application both IFBGs and dielectric sensors were embedded in the same carbon fibre epoxy composite. These were used together during the curing process to make in-situ measurements of internal strain and conductivity. The results obtained demonstrate that it is possible to monitor the strain levels in the optical fibre resulting from the onset of liquification, gelation, and vitrification within the surrounding resin matrix. For the impact detection application IFBGs were embedded in epoxy resin carbon fibre composite coupons, and these coupons were then subjected to impact events. In addition, a force transducer and resistive foil strain gauges were used to make parallel measurements of strain. Comparisons of the data obtained are provided. The IFBGs successfully survived the impacts and recorded strain transients that characterise typical fracture events. | en_UK |
| dc.description.coursename | PhD | en_UK |
| dc.identifier.uri | https://dspace.lib.cranfield.ac.uk/handle/1826/19601 | |
| dc.language.iso | en | en_UK |
| dc.title | Implementation and appraisal of an in-fibre Bragg grating quasi-distributed health and usage monitoring system with applications to advanced materials | en_UK |
| dc.type | Thesis | en_UK |
Files
Original bundle
1 - 1 of 1
Loading...
- Name:
- O'Dwyer_M 2000 PhD 1403570189 10832123.pdf
- Size:
- 19.34 MB
- Format:
- Adobe Portable Document Format
- Description:
License bundle
1 - 1 of 1
No Thumbnail Available
- Name:
- license.txt
- Size:
- 1.63 KB
- Format:
- Item-specific license agreed upon to submission
- Description: