A damage identification method based on cable force tests of a cable system and test error self-adaptive analysis is proposed to measure cable forces in prestressed steel structures and find out possible damage positions of the cable system. The method includes placing a laser velocimeter; measuring the vibration speed history data of the measuring point P on the cable by the laser velocimeter; calculating the cable force; calculating all the cable forces of the cable system through the same procedure; analyzing error between cables and finding out the possible damage of the cable or of the tie rod connected to the cable. The dynamic response characteristics of both in-plane and out-of-plane of a cable can be obtained through the method of the present invention. The self-verified more accurate results can be obtained, and the damage in a cable system can be determined according to error self-adaptive analysis.

A damage identification method based on cable force tests of a cable system and test error self-adaptive analysis is proposed to measure cable forces in prestressed steel structures and find out possible damage positions of the cable system. The method includes placing a laser velocimeter; measuring the vibration speed history data of the measuring point P on the cable by the laser velocimeter; calculating the cable force; calculating all the cable forces of the cable system through the same procedure; analyzing error between cables and finding out the possible damage of the cable or of the tie rod connected to the cable. The dynamic response characteristics of both in-plane and out-of-plane of a cable can be obtained through the method of the present invention. The self-verified more accurate results can be obtained, and the damage in a cable system can be determined according to error self-adaptive analysis.

A damage identification method based on cable force tests of a cable system and test error self-adaptive analysis is proposed to measure cable forces in prestressed steel structures and find out possible damage positions of the cable system. The method includes placing a laser velocimeter; measuring the vibration speed history data of the measuring point P on the cable by the laser velocimeter; calculating the cable force; calculating all the cable forces of the cable system through the same procedure; analyzing error between cables and finding out the possible damage of the cable or of the tie rod connected to the cable. The dynamic response characteristics of both in-plane and out-of-plane of a cable can be obtained through the method of the present invention. The self-verified more accurate results can be obtained, and the damage in a cable system can be determined according to error self-adaptive analysis.

A damage identification method based on cable force tests of a cable system and test error self-adaptive analysis is proposed to measure cable forces in prestressed steel structures and find out possible damage positions of the cable system. The method includes placing a laser velocimeter; measuring the vibration speed history data of the measuring point P on the cable by the laser velocimeter; calculating the cable force; calculating all the cable forces of the cable system through the same procedure; analyzing error between cables and finding out the possible damage of the cable or of the tie rod connected to the cable. The dynamic response characteristics of both in-plane and out-of-plane of a cable can be obtained through the method of the present invention. The self-verified more accurate results can be obtained, and the damage in a cable system can be determined according to error self-adaptive analysis.

An identification system (1) includes a transmitter (131) for transmitting pulsed light via an optical fiber (10); a receiver (132) for receiving backscattering light of the pulsed light from the optical fiber (10); a detector (133) for detecting, from the backscattering light, the condition of environment surrounding the optical fiber (10); and an identifier (320) for identifying sagging of the optical fiber (10) from a detection result by the detector (133).

An identification system (1) includes a transmitter (131) for transmitting pulsed light via an optical fiber (10); a receiver (132) for receiving backscattering light of the pulsed light from the optical fiber (10); a detector (133) for detecting, from the backscattering light, the condition of environment surrounding the optical fiber (10); and an identifier (320) for identifying sagging of the optical fiber (10) from a detection result by the detector (133).

A measurement system includes an imaging device, a memory device, an interface and circuitry. The imaging device is configured to obtain a device image a conveyor belt system. The image device is configured to obtain a reference image of a reference point or reference measurement. The reference image can also be the device image. The memory device is configured to store the device image. The interface is configured to facilitate selection of points for a device/part to be measured. The circuitry comprises one or more processors configured to determine a reference measurement for the reference dimension based on the reference image via the interface; determine one or more device measurements based on the device image and the reference measurement; and calculate a plurality of device parameters based on the determined one or more device measurements. User input via a touch sensitive screen comprising a glass insulator coated with indium tin oxide (ITO) and the one or more processors can be configured to select the one or more device points based on change in capacitance at one or more locations of the touch sensitive screen.

A measurement system includes an imaging device, a memory device, an interface and circuitry. The imaging device is configured to obtain a device image a conveyor belt system. The image device is configured to obtain a reference image of a reference point or reference measurement. The reference image can also be the device image. The memory device is configured to store the device image. The interface is configured to facilitate selection of points for a device/part to be measured. The circuitry comprises one or more processors configured to determine a reference measurement for the reference dimension based on the reference image via the interface; determine one or more device measurements based on the device image and the reference measurement; and calculate a plurality of device parameters based on the determined one or more device measurements. User input via a touch sensitive screen comprising a glass insulator coated with indium tin oxide (ITO) and the one or more processors can be configured to select the one or more device points based on change in capacitance at one or more locations of the touch sensitive screen.

This application describes a fibre optic cable structure which is advantageous for distributed fibre optic sensing, for example distributed acoustic sensing (DAS). The fibre optic cable structure includes an optical fibre for distributed fibre optic sensing and is configured to comprise at least one longitudinal section of a first type, which exhibits a change in effective optical path length of the optical fibre of one polarity in response to a given applied force, and which is adjacent to at least one longitudinal section of a second type, which exhibits a change in effective optical path length of the optical fibre of the opposite polarity in response to an equivalent applied force. When used for DAS, the response of a sensing portion that includes sections of both the first and second types, will include or exclude certain wavenumber by summation, which provides a directional sensitivity to incident waves.

An optical fiber measurement device includes a light source, a light detector, a direction-changing member, and a tension-applying member. The light source emits light toward an optical fiber. The light detector receives the light that has propagated through the optical fiber. The optical fiber is hung on the direction-changing member. The direction-changing member changes an extending direction of the optical fiber to extend downward, the optical fiber being optically connected to the light source and the light detector at each of two end parts of the optical fiber. The tension-applying member applies a tension to the optical fiber hanging from the direction-changing member.