University of Twente Student Theses
Bare Fibre Optic Sensors for Strain and Temperature Measurements in Surface-layer Asphalt : An Implementation and Evaluation Case Study
Pozinãrea, S. (2022) Bare Fibre Optic Sensors for Strain and Temperature Measurements in Surface-layer Asphalt : An Implementation and Evaluation Case Study.
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| Abstract: | Demands are increasing in the field of road vehicle transportation and with them there is an increasing need for improvements in road infrastructure maintenance and health monitoring. Structural health monitoring takes charge of this issue by, among other methods, making use of sensors for continuous monitoring and assessment. Fibre optical sensors are on the cusp of becoming the go-to alternative among such sensors, due to their many technological advantages. However, they pose just as many if not additional issues and the decision-making behind their appropriate implementation is far more complex. We can identify two instances of usage. One instance is meant for high-performance measurements, case in which the optical fibre is not coated, and the second instance where the optical fibre cables are used in harsher environments, generally while coated, and provide less accurate measurements. In the field of road maintenance and structural health monitoring, the second instance is far more common and other more traditional sensors are used. This study thus tackles two issues. Firstly, could or should the older sensors be replaced with the new fibre optical technologies, considering the benefits of the more advanced technology. Secondly, regarding the discussion of coating usage and accuracy, the study aims to give some new perspectives on the decision-making and challenge the unspoken consensus about the use of coatings. In order to achieve this, the study involves the observation of a paving project on the University of Twente campus in Enschede, Overijssel. During this study, fibre optic sensors are used for measuring temperature and strain in the asphalt layer. The results are then evaluated with data from traditional sensors and theoretical values. The evaluation process is meant to establish whether or not the measurements are reliable and accurate. The difference is that the project team aims to test the high-performance uncoated sensors in what would generally be considered a harsh environment. Lastly, a comprehensive discussion of the results and research questions is presented alongside a research conclusion and a proposal for future inquiries in this field. Although the project’s on-site implementation has led to some failure by various mechanisms, one significant conclusion was derived, alongside a few more insights into fibre optic installation and usage. Moreover, the hinderances in data collection have prevented part of the data evaluation process from allowing a concrete assessment. However, the study has been concluded and is to be used in preparation of future renditions of the paving project and fibre optic sensor research. The main objective of the study was to generate a calibration and evaluation framework for strain and temperature, offering the opportunity to replace other types of sensors in the future. Although, the data is not optimal, the regression results over all 5 data sets point towards a possibly valid procedure for the evaluation of strain measurements. This could suggest that the FOS can indeed be a functional replacement for the traditional strain gauge. As for the other research questions, it is rather clear that the data retrieved from bare FOS is not satisfactory. Because of that, for the moment, the bare FOS cables cannot be recommended as a functional replacement for both strain and temperature measurements. Lastly, there is high emphasis on the downfalls of bare FOS and the usage of coating, suggesting that adequate coatings can indeed improve the quality of the study were it to be reiterated. |
| Item Type: | Essay (Bachelor) |
| Faculty: | ET: Engineering Technology |
| Programme: | Civil Engineering BSc (56952) |
| Link to this item: | https://purl.utwente.nl/essays/89819 |
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