Finite element prediction of resin pocket geometry around embedded optical fiber sensors in prepreg composites

This work presents a finite element technique allowing for the accurate prediction of resin pocket geometries surrounding optical fiber sensors in UD prepreg composites. The F.E. implementation solely relies on material models and element formulations readily available in all commercial F.E. codes, rather than requiring specialized user developed element and material formulations. In addition, only a minimal amount of straight-forward experimental characterization is required to determine the necessary material parameters in the model. The F.E. results are validated with microscopic images of several lay-ups with embedded optical fiber samples of different diameters. Very good correspondence is found between F.E. results and microscopic cross-sections, showing the usefulness and applicability of the method to random lay-ups and optical fiber dimensions.