Abstract

Bragg Grating based optical fibre sensors are widely used for structural monitoring. Its operation is theoretical well known when deformations are measured along the fibre axes. Nevertheless, transverse deformations of the optical fibre have an effect that affects the performance of the sensors. This transverse effect has not been so deeply studied as the longitudinal and it is less known. When a sensor is embedded in a composite structure, its deformation is rarely unidirectional because of the presence of complex loads cases and/or the Poisson module effect on the deformation of the lamination.

A test campaign of biaxial composite material specimens with embedded fibre optic sensors is going to be performed. The work pursues to create controlled deformation cases to the sensor in the two main axes of its plane, by means of perpendicular loads in each axis. Following this test methodology in the plane, it will be observed the influence of the transverse deformations on the values of the longitudinal deformation measured by the sensors.

To carry out the biaxial tests it has been used equipment that allows the control of the applied load in the three coordinate axes independently. It also been used a digital image correlation (DIC) equipment for measuring the deformations. Characterization of the sensors will be carried out with different load case tests.