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.

There is a large potential to integrate substantial shares of renewable energy and waste heat sources in district heating and/or cooling networks (DHC), reducing dependency of DHC on fossil fuels and ultimately leading to a more efficient and sustainable energy system. Several EU funded projects are currently working on this topic. The objective of the workshop aimed to share the WEDISTRICT project concept with other sister projects and interested stakeholders in order to exchange new ideas, lessons learnt from implementation and proposals about the successful integration of renewable technologies in DHC and urban regeneration.

No abstract