Abstract
Optical fibre-based sensor systems are being used increasingly in civil engineering applications where structural integrity monitoring is of interest or concern. This paper reports on an optimisation scheme for an optical fibre-based sensor protection system designed to protect and enhance the strain-transfer characteristic when it is embedded in concrete. The sensor protection system consisted of a stainless steel tube with specified flange designs. Three flange designs were considered: disc, cone and inverted cone. Non-linear finite element analysis incorporating contact logic was performed to select and optimise the shape and dimensions of the flange. The analysis showed high stress concentrations in the vicinity of the flanges. However, this effect was localised and was not transmitted to the intended location of the sensor. The results showed that all three flange designs were effective but the 5 mm diameter disc-shaped flange gave the best results in terms of the magnitude and symmetry of the shear stress at the tube-concrete interface.
Résumé
Les systèmes de capteurs à fibres optiques sont de plus en plus utilisés dans des applications de génie civil, où la surveillance, de l'intégrité structurale est concernée. Cet article rend compte du procédé d'optimisation d'un système de protection par capteurs à fibres optiques conçu pour protéger et mettre en valeur la caractéristique du transfert de contrainte lorsqu'il est encastré dans du béton. Ce système de protection par capteurs est composé d'un tube en acier inoxydable avec des formes de brides déterminées. Trois formes de brides ont été prises en considération: disque, cône et cône inversé. Une analyse non linéaire par éléments finis incorporant une logique de contact a été réalisée afin de choisir et d'optimiser la forme et les dimensions de la bride. Cette analyse a montré de fortes concentrations de contraintes à proximité des brides. Cependant, cet effet a été localisé et n'a pas été transmis à l'emplacement prévu du capteur. Les résultats ont prouvé que chacune des trois formes de bride était pertinente mais que la bride en forme de disque de 5 millimètres de diamètre a donné les meilleurs résultats en termes d'ampleur et de symétrie de la contrainte de cisaillement à l'interface tube-béton.
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Abbreviations
- Fs :
-
force in steel bar
- Ss :
-
stress in steel bar
- Sbu :
-
ultimate anchorage bond stress
- So :
-
ultimate concrete stress
- Sb :
-
anchorage bond stress
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Hameed, A., Fernando, G.F., Hetherington, J.G. et al. Investigation of strain transfer to a sensor protection system embedded in concrete using finite element analysis. Mat. Struct. 35, 557–563 (2002). https://doi.org/10.1007/BF02483124
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DOI: https://doi.org/10.1007/BF02483124