A system for performing distributed measurements of in-situ stress includes an expandable element with at least one fiber optic sensor. The expandable element can be positioned at various depths in a hole in a substrate. A pressurizing device expands (and contracts) the expandable element when the expandable element is inserted in the hole in the substrate to exert pressure on the hole wall. A pressure sensor provides a sensor output indicative of a pressure applied to the hole wall by the expandable element. The fiber optic sensor and an optical interrogator measure strain along a length of the sensor in a continuous, high spatial resolution manner Based on the measured strain and pressure sensor output, the system determines various properties of the substrate such as, minimum principal stress, maximum principal stress, and/or principal stress direction associated with one or more fractures in the substrate, as well as substrate modulus.

The present disclosure relates to a stretchable fiber optic sensor that can measure tension, bending, and torsion direction of an object. The fiber optic sensor includes an optical fiber with a fiber Bragg grating (FBG) embedded in a sinusoidal configuration at an off-center position of a deformable substrate.

Fibre optics for distributed environmental condition and/or air quality sensing such as, but not limited to, sensing air quality in enclosed areas of an aircraft such as the passenger cabin. Fibre optics can be used for sensing and for communication and are therefore well suited to the distributed sensing of environmental conditions such as temperature, relative humidity, gas and particulate composition within spaces of the aircraft e.g. the cabin, cargo space, cockpit, electronics bay etc. and in related systems such as the environmental control system (ECS), the cabin recirculation system, bleed air system etc.

An energy storage module for a vehicle includes an energy storage enclosure adapted to accommodate an energy storage cell, the energy storage enclosure having an enclosure wall, an optical sensor including an optical fiber, an optical receiver and an optical emitter, the optical fiber attached to an inner side of a first enclosure wall along a distance of a portion of the inner side. The optical receiver is configured to detect an optical signal transmitted through the optical fiber, and the optical sensor is configured to detect an alteration of the optical signal being indicative of a deformation.

An apparatus for assessing balance is described comprising a light source; a light guide; and a light detector. The light source is arranged to introduce light into the light guide; the light guide is arranged to be stood upon by a subject; the light detector is arranged to detect light emanating from the light guide to thereby facilitate an assessment of the balance of the subject standing upon the light guide.

This application relates to a fibre optic cable structure suitable for use as a sensing fibre optic for distributed acoustic sensing and having an improved sensitivity to transverse pressure waves. The application describes a fibre optic cable (300) having a longitudinal cable axis and comprising at least one optical fibre (301). The cable also comprises a compliant core material (303) mechanically coupled to the optical fibre(s), possible via a buffer (302) such that a longitudinal force acting on the compliant core material induces a longitudinal strain in the optical fibre(s). At least one deformable strain transformer (304) is coupled to the compliant core material and configured such that a force acting on the strain transformer in a direction transverse to the cable axis results in a deformation of the strain transformer thereby applying a longitudinal force to the compliant core material.

A sensor arrangement using an optical fiber and methodologies for performing an analysis of a subterranean formation, such as a subterranean formation containing a hydrocarbon based fluid. The sensor arrangement may be used to measure one or more physical parameters, such as temperature and/or pressure, at a multiplicity of locations in the subterranean reservoir. The sensor arrangement may comprise a sensor array comprising an elongated outer casing for insertion in the subterranean formation and into a fluid in the subterranean formation. The sensor array may comprise an optical fiber defining an optical path that links one or more temperature sensors and one or more pressure sensors and transports measurement data generated by the temperature and pressure sensors. A data processing system may be connected to the sensor array to receive measurements from the sensor array and to compute one or more values of a property of an extraction installation operating on the subterranean formation.

This evaluating method is an evaluating method for evaluating an assembly (50) provided with a reinforced member (60) and a reinforcing member (70), and includes: a step of introducing incident light into a first optical fiber (20) extending between a first composite layer and a second composite layer and detecting outgoing light therefrom to measure a first strain distribution, and introducing incident light into a second optical fiber (30) extending between the second composite layer and a third composite layer and detecting outgoing light therefore to measure a second strain distribution; and a step of acquiring the shape of wrinkles at the surface (60s) of the reinforced member (60) from the first strain distribution and the second strain distribution.

Pressure sensing having 2-D resolution is provided by an array of optical waveguides having wave-guide intersections (e.g., intersecting rows and columns). Pressure induced cross-coupling between intersecting wave-guides is enhanced by including mechanical structures at each intersection that enhance local waveguide bending. For example, such structures can be rigid rings around the wave-guide intersections.

The optical sensor generally has a frame having a deformable member mounted to the frame, and a sensing optical fiber being fixedly attached to a portion of the deformable member, the sensing optical fiber having at least one -phase-shifted fiber Bragg grating inscribed thereon, the at least one -phase-shifted fiber Bragg grating of the sensing optical fiber deforming together with the deformable member when the frame is subjected to a force.