Inclinometer with bragg grating
AssigneeCommissariat a l'Energie Atomique
InventorsPierre Ferdinand, Stéphane Rougeault
Life of this patent
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Abstract
A Bragg grating inclinometer that includes an upper part, a lower part forming a pendulum suspended from the upper part by an articulation, at least two portions of optic fiber placed on either side of the articulation, the ends of each portion being fastened to the two parts, each portion being previously put under tension between the two parts, and at least one Bragg grating in one of the portions. Any variation in the inclination of a structure to which the upper part is fastened induces a stress on the grating, which then modifies a light propagating in the portion where it is placed. The variation in inclination is determined from the modified light. The inclinometer can be applied in particular to the surveillance of civil engineering structures.
Claims12
Inclinometer configured to measure an inclination variation of a structure, said inclinometer comprising:
- an upper part configured to be rendered rigidly integral with the structure so that inclination of said upper part varies like that of the structure;
- a lower part configured to be located below the upper part;
- an articulation of the lower and upper parts, the lower part forming a pendulum freely suspended from the upper part by the articulation;
- at least two portions of optic fiber placed on either side of said articulation, each portion of optic fiber having first and second ends respectively fastened to the lower and upper parts and previously put under tension between the lower and upper parts;
- and
- at least one Bragg grating formed in one of the two portions of the optic fiber,
- wherein any variation in inclination of the structure provokes a rotation of the upper part in relation to the lower part and induces, as a result, a stress on the Bragg grating, said Bragg grating configured to modify a light that propagates in a portion of optic fiber where said Bragg grating is located, variation in the inclination of the structure being determined from the light thereby modified by the Bragg grating.
Dependencies are inferred from the claim text.