A technique facilitates the use and application of a distributed vibration sensing system in, for example, a well application. The technique enables selection of a desired gauge length to achieve an optimum trade-off between the spatial resolution of a distributed vibration sensing/distributed acoustic sensing system and signal-to-noise ratio. The optimum gauge length can vary according to specific factors, e.g. depth within a well, and the present technique can be used to account for such factors in selecting an optimal gauge length which facilitates accurate collection of data on dynamic strain.

The present invention relates to a stress-strain testing system for a large-diameter steel pipe pile of an offshore wind turbine and a construction method, comprising a steel pipe pile, wherein copper belt type sensor cables are correspondingly welded on both sides of the steel pipe pile along an axis direction; each sensor cable is sequentially covered with an epoxy adhesive, gold foil paper and an angle steel welded on the steel pipe pile centering on the copper belt type sensor cable; a fiber core of each copper belt type sensor cable is transferred into a high-strength armored optical cable by a special fixture and then is led out; and the high-strength armored optical cable is connected with a Brillouin optical fiber demodulator. The present invention is applicable to the field of foundation engineering testing and detection technology.

Methods, systems, devices, and products for ultrasonic borehole logging using an ultrasonic borehole imaging tool in a borehole intersecting the earth formation. Methods may include adjusting a focus for an ultrasonic beam generated from a single-transducer ultrasonic assembly of the ultrasonic imaging tool; using a receiver to generate measurement information responsive to an ultrasonic signal caused by the ultrasonic beam; and estimating a parameter of interest from the measurement information. Methods may include adjusting the focus in dependence upon environmental conditions, the environmental conditions comprising at least one of: i) standoff between the ultrasonic imaging tool and a wall of the borehole; and ii) borehole annulus conditions. Methods may include adjusting the focus in substantially real-time. The ultrasonic beam may be focused with a focal zone at the borehole wall configured to produce a beam spot size of a selected diameter.

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 pressure sensor for a pipe includes: a flexible strip; at least one strain sensing element; and a tensioning device. A first end of the flexible strip passes through a second end of the flexible strip. Between the first end of the flexible strip and the second end of the flexible strip, the flexible strip includes the at least one strain sensing element. The pressure sensor is attachable to the pipe. The first end of the flexible strip extends through or past the second end of the flexible strip. The tensioning device tensions the pressure sensor around the pipe.

Methods, systems, and apparatuses are provided for detecting and determining conditions of and conditions within a fluid conduit.

The present disclosure discloses a method for calculating an internal explosion load speed based on an incremental crack growth distance of a pipeline. The method includes steps of: respectively measuring at least three groups of distances between neighboring markings on forward and backward crack surfaces, and calculating the average values respectively to obtain the average incremental growth distances of forward and backward cracks; calculating the natural vibration frequency of the pipeline; and setting the ratio of backward crack speed to forward crack speed of the pipeline, then calculating the internal explosion load speed of the pipeline by a formula. The present disclosure provides a new effective method for calculating the internal explosion load speed based on the available parameters of the ruptured pipeline after explosion, which can provide a comparatively accurate estimation of internal explosion load speed, thereby providing references for inferring the explosion type occurred in the pipeline.

A method of monitoring the health of an aircraft propeller whilst the propeller is in operation, the propeller having a plurality of blades extending radially outwardly from hub arms of a propeller hub, which in turn extend radially outwardly from a central axis extending through the propeller and a propeller drive shaft, is provided. The method comprises obtaining measurements representative of the strain in each of at least some of the hub arms using strain sensors, each of the strain sensors being provided on a respective hub arm. A corresponding propeller health monitoring system, an aircraft propeller comprising the system and an aircraft comprising the propeller are also provided.

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 method and arrangement of fibre optic distributed sensing for detection of an event at an event location within a blind region including using at least one optical fibre arranged at least partly along an object to be monitored and at least one light pattern interrogator coupled with the optical fibre; injecting light patterns at subsequent times; detecting backscatter light from the light patterns; and analyzing the backscatter light to determine the event location so that a detection range of the fiber optic distribution range of the fiber-optic distributed sensing system is extended into a blind region conventionally not accessible for detecting acoustic disturbances or acoustic events.