Abstract: A pipe comprises a pipe wall formed of a composite material of a matrix and a plurality of reinforcing fibres embedded within the matrix, wherein the composite material in at least one region of the pipe wall is pre-stressed. The composite material in at least one region of the pipe wall comprises or defines at least one of a level of pre-tension and pre-compression.

Abstract: A pressure sensor (10) comprising fibre Bragg grating (FBG) strain sensors (12) provided within an optical fibre (14), an optical fibre strain sensor carrier rod 16 and a pressure intensifying sleeve (18). The carrier rod (16) is formed from a first glass fibre reinforced epoxy resin composite material having a first stiffness/elastic modulus the direction of strain sensing. The sleeve (18) is formed from a second composite material, having a lower axial stiffness in the direction of strain sensing than that of the carrier rod (16). Under an applied hydrostatic load, the sleeve (18) exerts an axial compressive load onto the section of rod (16) within the sleeve (18). The axial compressive strain experienced by the rod (16) is thereby increased in the region within the sleeve (18) compared to the axial compressive strain that would be produced in the rod (16) if the sleeve (18) was not present.

Abstract: A vibration detector (1) comprising at least one fibre optic sensor (2) mechanically coupled to a flexible support member (3). The vibration detector (1) is mounted on the outside of the pipeline and a signal from the fibre optic sensor is measured. This signal is indicative of whether the vibration detector is experiencing vibrations due to collisions of contaminant particles with each other and/or with the walls of the pipeline. A method for detecting particulate contaminants in a fluid flowing in a pipeline is also provided.

Abstract: A load monitoring system for wind turbine blades utilizes optical fibre strain sensors (5) moulded into the turbine blades. A sensor monitoring instrument is located in the hub (3) of the turbine. Various arrangements of cabling are disclosed to maximize fault tolerance. Various arrangements of a temperature compensation device for the strain sensors is also disclosed. The strain sensors (5) and optical fibre (7) may be provided on a pre-cured patch (9) for incorporation in the structure of the turbine blade. Furthermore, it is disclosed that each blade comprises an optical fibre strain sensor and a cable to connect the sensors to processing equipment, wherein each such cable includes a connector at each end whereby each blade can be replaced independently. Also, it is shown to provide an output connector for connecting the sensor to processing equipment in a cavity that is filled with a material for inhibiting free movement of the output connector.

Abstract: A curvature sensing device 10 comprising, a first fibre Bragg grating (FBG) strain sensor 12, a second FBG strain sensor 14, a flexible piece comprising two end pieces 16, 18 joined by a tubular mid-section 20. The device 10 further comprises 16 contact rollers 22 provided on the internal surfaces of the end pieces 16, 18, which maintain the end pieces 16, 18 tangential to a pipe around which the device 10 is located. The FBG strain sensors 12, 14 are embedded within the mid-section 20 and are arranged in two generally orthogonal planes, so that the curvature is measured in two dimensions. This enables the device 10 to detect both the magnitude and direction of bending/curvature within a pipe. Bending in a pipe is transferred through the end pieces 16, 18 to the mid-section 20. The FBG sensors 12, 14 measure bending of the mid-section 20 from which bending of the pipe can be inferred.

Abstract: Structural joint strain monitoring apparatus 92 comprises jacket means 52 in the form of first and second jacket elements 62, each having a primary jacket part 62a and substantially perpendicular secondary jacket part 62b which together define a compartment for receiving a joint, between two pipes 54, 56, to be monitored. The jacket means 52 additionally comprises two primary web elements 76, 78 provided between the primary and secondary jacket parts 62a, 62b. Three fiber Bragg grating (FBG) strain sensors 96, 98, 100 and an FBG temperature sensor 102 are provided within an optical fiber 104, bonded to the primary web elements 76, 78 and each end of the second jacket element 62 respectively, for measuring strain or temperature at their respective locations. The FBG sensors 96, 98, 100, 102 are optically coupled, via optical fiber 104, to optical fiber sensor interrogation apparatus 94, operable to interrogate each FBG sensor.

Abstract: Apparatus (10) for monitoring changes in the shape of a hollow structure (20) comprises a flexible elongate support (12), which includes several optical fibre strain sensors (14, 16, 18) each arranged to measure strain in the longitudinal direction of the support (12). The strain sensors (14, 16, 18) are spaced in a direction perpendicular to the longitudinal direction of the support and the support is adapted to bear against the inner surface of the hollow structure (20), such that changes in shape of the structure along the longitudinal direction result in generally corresponding changes in shape of the support.

Abstract: Structural joint strain monitoring apparatus 92 comprises jacket means 52 in the form of first and second jacket elements 62, each having a primary jacket part 62a and substantially perpendicular secondary jacket part 62b which together define a compartment for receiving a joint, between two pipes 54, 56, to be monitored. The jacket means 52 additionally comprises two primary web elements 76, 78 provided between the primary and secondary jacket parts 62a, 62b. Three fibre Bragg grating (FBG) strain sensors 96, 98, 100 and an FBG temperature sensor 102 are provided within an optical fibre 104, bonded to the primary web elements 76, 78 and each end of the second jacket element 62 respectively, for measuring strain or temperature at their respective locations. The FBG sensors 96, 98, 100, 102 are optically coupled, via optical fibre 104, to optical fibre sensor interrogation apparatus 94, operable to interrogate each FBG sensor.