Ballistic damage detection in thermoplastic composite laminates by means of embedded optical fibers

Fiberoptic sensors (FOS), can be either placed on the material surface or can be embedded into the material structure. A network of fiberoptic sensors within composite materials provides real-time information about any deformation in material during manufacturing process or material use. The main advantages of fiberoptic sensors are their shape and structure which result in easy embedding, preserving composite material mechanical properties, which makes them a reliable automatic system for long-term structure health monitoring. Thermoplastic reinforced composite materials were made for increased material damage resistance during ballistic loading. This article the describes procedure of embedding fiberoptic sensors in laminar thermoplastic composite material, as well as damage investigation after ballistic loading. Damage inside the composite material was detected by observing intensity drop of the light signal transmitted through the optical fiber network. Experimental testing was carried out in order to observe and analyze the response of material under various load conditions.