Additively manufactured components enable complex structures to be rapidly fabricated and tested for use in the automotive and aerospace industries. Additive manufacturing capabilities have expanded to include a variety of plastics, metal alloys, and fiber-reinforced polymers. There is interest in quantifying the residual stresses in components that have been manufactured using 3D printing processes in order to refine fabrication parameters and improve the performance of component design. Luna Innovations has developed and demonstrated methods to embed high definition fiber optic sensing (HD-FOS) technology into components that have been additively manufactured using ABS plastic as well as a cobalt chrome alloy. This technology enables characterization of internal residual stresses and provides a method for lifetime health monitoring of these printed components using the strain and temperature sensors installed during printing. The sensing technology utilizes the Rayleigh backscatter pattern contained in an optical fiber to determine the strain or temperature, with a high spatial resolution of 1.28 mm, along a fiber that can be embedded inside a printed component. HD-FOS technology was used to measure internal residual strains within layers of varying depths of an ABS printed block, showing a parabolic strain profile with a peak at 9,600 microstrain. In addition to characterizing the printing process, a method has been demonstrated to embed a distributed temperature sensor into a metallic additively manufactured component. This enables the temperature of the part to be measured while it is in use, providing data on the heat transfer through the component. Additive manufacturing has enabled embedding fiber optic sensors in new configurations that were previously unobtainable.

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