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Modeling the effects of temperature gradients on the dynamic properties of a girder
Cracanuta, A. (2025) Modeling the effects of temperature gradients on the dynamic properties of a girder.
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| Abstract: | Structural Health Monitoring (SHM) aims to detect and locate damage in civil structures by monitoring and analyzing their structural responses over time. One of the methods of damage detection is the vibration based approach. It relies on changes in modal parameters, which occur in the event of damage introduction. But modal parameters can also be affected by environmental factors. This thesis investigates the impact of certain temperature gradient assumptions on the reliability of vibration based damage detection. A Finite Element Model (FEM) of a simply supported HE 200B steel girder was subject to a coupled-field analysis which involved a pre-stressed modal analysis given the results of a transient thermal analysis. Two thermal loading scenarios were investigated: spring and winter. They involved hourly data on sun irradiance and ambient temperature, for two separate days. The study compared the effects of the realistic temperature distributions with those of a uniform temperature on the frequencies of the first three modes of the girder. Lastly, damage was introduced to evaluate whether its effects on dynamics are more or less pronounced than those of temperature. The results show that the assumption that the girder has the same temperature as the ambient introduces error in modal frequency computing, especially for mode 1 (lateral) and mode 2 (torsional). Meanwhile, mode 3 (vertical) remained insensitive to them. But the relative errors followed the same pattern as the ambient temperature. When structural damage was introduced, the thermal effects either masked or exacerbated its effects depending on the studied mode. |
| Item Type: | Essay (Bachelor) |
| Faculty: | ET: Engineering Technology |
| Programme: | Civil Engineering BSc (56952) |
| Link to this item: | https://purl.utwente.nl/essays/107871 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
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