Fiber Bragg Sensors Embedded in Cast Aluminum Parts: Axial Strain and Temperature Response
Markus Lindner,
Andrea Stadler,
Georg Hamann,
Bennet Fischer,
Martin Jakobi,
Florian Heilmeier,
Constantin Bauer,
Wolfram Volk,
Alexander W. Koch,
Johannes Roths
Affiliations
Markus Lindner
Photonics Laboratory, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich, Germany
Andrea Stadler
Photonics Laboratory, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich, Germany
Georg Hamann
Photonics Laboratory, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich, Germany
Bennet Fischer
Institut National de la Recherche Scientifique (INRS), Centre Énergie Matériaux Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, QC J3X 1S2, Canada
Martin Jakobi
Institute for Measurement Systems and Sensor Technology (MST), Technical University of Munich (TUM), Arcisstr. 21, 80333 Munich, Germany
Florian Heilmeier
Chair of Metal Forming and Casting (UTG), Technical University of Munich (TUM), Walther-Meißner-Straße 4, 85748 Garching, Germany
Constantin Bauer
Chair of Metal Forming and Casting (UTG), Technical University of Munich (TUM), Walther-Meißner-Straße 4, 85748 Garching, Germany
Wolfram Volk
Chair of Metal Forming and Casting (UTG), Technical University of Munich (TUM), Walther-Meißner-Straße 4, 85748 Garching, Germany
Alexander W. Koch
Institute for Measurement Systems and Sensor Technology (MST), Technical University of Munich (TUM), Arcisstr. 21, 80333 Munich, Germany
Johannes Roths
Photonics Laboratory, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich, Germany
In this study, the response of fiber Bragg gratings (FBGs) embedded in cast aluminum parts under thermal and mechanical load were investigated. Several types of FBGs in different types of fibers were used in order to verify general applicability. To monitor a temperature-induced strain, an embedded regenerated FBG (RFBG) in a cast part was placed in a climatic chamber and heated up to 120 ∘C within several cycles. The results show good agreement with a theoretical model, which consists of a shrink-fit model and temperature-dependent material parameters. Several cast parts with different types of FBGs were machined into tensile test specimens and tensile tests were executed. For the tensile tests, a cyclic procedure was chosen, which allowed us to distinguish between the elastic and plastic deformation of the specimen. An analytical model, which described the elastic part of the tensile test, was introduced and showed good agreement with the measurements. Embedded FBGs - integrated during the casting process - showed under all mechanical and thermal load conditions no hysteresis, a reproducible sensor response, and a high reliable operation, which is very important to create metallic smart structures and packaged fiber optic sensors for harsh environments.