Embedded fibre optic sensors within additive layer manufactured components

Smart materials with integrated sensing capabilities are now ubiquitous in many structures manufactured from composite materials and offer enhancement to the safety, reliability and efficiency of the resulting devices.
This paper explores the application of embedded sensors to components manufactured using Additive Layer Manufacturing (ALM) technology. ALM offers the ability to create physical parts with little or no restriction in shape complexity. In this paper, optical fibre sensors incorporating fibre Bragg gratings (FBGs) were embedded inside a component made during a powder bed based layer-by-layer additive manufacturing process using a commercial EOS P730 system, where a laser was used to sinter the polymeric powder into a three dimensional component.
The approach is based upon insertion of a ‘fibre-carrier’ component which replaced a removable ‘place-holder’ component during an interruption of the ALM build process.
Tensile test specimens fabricated this way have been subjected to extended cyclic tensile loading trials at low strain levels of up to 475 µe. The test specimens demonstrated stable and reproducible responses over a period in excess of 720 days and 311,000 load cycles.
Polyimide (PI) and acrylic (PMMA) jacketed fibres have been trialled and the resulting deformations of the component through internal stresses depending on the fibre jacket type are discussed.