Fibre optic strain and configuration sensing in engineering components produced by additive layer rapid manufacturing

Additive layered rapid manufacturing offers the ability to create physical parts with little or no restriction from shape complexity. Modelling and validation of this new technology requires embedded sensors which challenges conventional sensor technology. In this work, fibre Bragg gratings [FBG] have been embedded inside components made from a polymer during the manufacturing process of layer-by-layer additive manufacturing technology by laser sintering of powder layers using a commercial EOS P730 system. The technique is based on the insertion of a fibre carrier component, replacing a removable `place holder´ during an interruption of the build process. Tensile test specimens have been subjected to extended cyclic tensile loading trials at low strain levels of up to 400 μ-strain. The test specimen show stable and reproducible response over a period in excess of 330 days and 142000 load cycles. Polyimide and acrylic jacketed fibres have been trialled and the effect of minor deformations of the component through internal stresses depending on the fibre jacket type is discussed.