Multi-axial strain transfer from laminated CFRP composites to embedded Bragg sensor: I.Parametric study

Abstract

Embedded optical fibre sensors are considered in numerous applications for structuralhealth monitoring purposes. However, since the optical fibre and the host material in whichit is embedded, will have different material properties, strain in both materials will not beequal when load is applied. Therefore, the multi-axial strain transfer from the hostmaterial to the embedded sensor (optical fibre) has to be considered in detail.In the first part of this paper the strain transfer will be determined using finite elementmodelling of a circular isotropic glass fibre embedded first in an isotropic host and secondin an anisotropic composite material. The strain transfer or relation depends on themechanical properties of the host material and the sensor (Young’s modulus and Poisson’sratio), on the lay-up of the composite material (uni-directional lay-up/cross-ply lay-up) andthe position of the sensor in a certain layer. In the second part of the paper the developedstrain transfer model will be evaluated for one specific lay-up and sensor type.