Patent ID: 7174061

Claim:
Extensometer to measure the deformations of a host material this extensometer comprising at least one test specimen and at least one Bragg grating formed in an optic fibre which is made integral with the test specimen, any deformation of the host material being transmitted to the Bragg grating via the test specimen, the Bragg grating configured to then being able to modify a light propagating in the fibre, the deformation of the host material being determined using the modified light, the extensometer being characterized in that the test specimen undergoes linear bending stresses while remaining within its range of elastic deformation, and in that this extensometer also comprises mechanical means able to transform deformation of the host material into bending of the test specimen, this bending deforming the Bragg grating, wherein the mechanical means comprise a first part, intended to be made rigidly integral with the host material and in which the test specimen is fixed, and a second part also intended to be made rigidly integral with the host material and which is able to move within the first part and to cause bending of the test specimen.