Metal embedded Fiber Bragg Grating sensors in layered manufacturing

Layered Manufacturing can build functional "smart" parts with sensors, integrated circuits, complete functional assemblies, and actuators placed within the structure and fully embedded. These sensors can be used to gain data for validating or improving designs during the prototype stage or to obtain information on the performance and structural integrity, of functional components in service. A sequence for embedding fiber optic sensors in metals via Layered Manufacturing is developed. Fiber Bragg Grating (FBG) sensors, embedded in nickel and stainless steel were characterized for temperature and strain measurements. Moreover a decoupling technique that is capable of separating temperature and strain effects was also developed. This paper also presents the application of the embedded sensors to monitor residual strains during laser-assisted Layered Manufacturing.