Strain measurement device and installation of such a device in an element

1. A strain measurement device, comprising:

at least one filiform strain sensor;

a support of longilinear shape on which the filiform strain sensor is positioned; and

a stiffener;

wherein the stiffener and a wall of the support are coupled together so as to define a space between the stiffener and the wall of the support so that the support retains a freedom of movement with respect to bending.

2. The device according to claim 1 , wherein the stiffener is at most fixed to the support at one point.

3. The device according to claim 1 , wherein the filiform strain sensor is an optical fibre Bragg grating.

4. The device according to claim 1 , wherein the support is hollow, and has a longitudinal direction and a width, with the support further comprising a wall having a thickness and having an external surface on which the filiform strain sensor is positioned by one or more connecting points, a main strain direction of the filiform strain sensor being arranged parallel to the longitudinal direction of the support.

5. The device according to claim 4 , wherein one end of the support is blocked.

6. The device according to claim 5 , wherein the support is blocked by a cap an end of which extends beyond the end of the support.

7. The device according to claim 1 , wherein the device comprises a thin tube encapsulating at least the filiform strain sensor with a binder.

8. The device according to claim 4 , further comprising an additional strain sensor, free of deformation with respect to the support, and situated in an internal volume defined by the wall of the hollow support.

9. A structural element, comprising:

a first surface;

a hole having a first end that opens onto a first surface;

a strain measurement device received in at least one measurement zone associated with the hole, the strain measurement device including at least one filiform strain sensor, a support of longilinear shape on which the filiform strain sensor is positioned and a stiffener; and

a binder forming a film surrounding the strain measurement device;

wherein the stiffener and a wall of the support are coupled together so as to define a space between the stiffener and the wall of the support so that the support retains a freedom of movement with respect to bending.

10. The structural element according to claim 9 , wherein the hole has a second end which is closed.

11. The structural element according to claim 9 , wherein the hole is at least approximately coaxial with an axis of symmetry of the element.

12. The structural element according to claim 9 , wherein the stiffener is at most fixed to the support at one point.

13. The structural element according to claim 9 , wherein the filiform strain sensor is an optical fibre Bragg grating.

14. The device according to claim 1 , wherein the stiffener is removeably coupled to the support.

15. The structural element according to claim 9 , wherein the stiffener is removeably coupled to the support.

16. A strain measurement device, comprising:

at least one filiform strain sensor;

a support of longilinear shape on which the filiform strain sensor is positioned; and

a stiffener;

wherein the support is hollow, and has a longitudinal direction and a width, with the support further comprising a wall having a thickness and having an external surface on which the filiform strain sensor is positioned by one or more connecting points, a main strain direction of the filiform strain sensor being arranged parallel to the longitudinal direction of the support, and

wherein the stiffener and a wall of the support are coupled together so as to define a space between the stiffener and the wall of the support so that the support retains a freedom of movement with respect to bending.