34 results about "Hoop strain" patented technology

A metering apparatus for determining a characteristic of a fluid, such as the volumetric flow rate, flowing through a non-linear section of a pipe is disclosed having a first strain gauge mountable to the non-linear section of the pipe offset from the bending neutral axis of the non-linear section of the pipe, to detect a bending force on the non-linear section of the pipe induced by the inertia of the fluid flowing through the pipe. A second strain gauge is mountable to the pipe disposed on the bending neutral axis of the non-linear section of the pipe, to detect at least one of the hoop strains, longitudinal strains and radial strains imparted on the pipe by the pressure of the fluid flowing through the pipe. A controller is configured to determine the mass flow rate of fluid flowing through the pipe based on the bending force determined by the first strain gauge and the at least one of the hoop strains, longitudinal strains and radial strains determined by the second strain gauge.

The invention provides a calculation method of a pipe joint hoop strain of a tide load sinking pipe tunnel. The method includes steps of, assuming a back silt layer on the pipe joint as an impervious bed, and regarding the change of the tide level as a large area load pO added on the impervious bed, wherein the location of an underground level is the top face of the impervious bed; not considering about influence of tide on the pipe joint structure, calculating water, soil pressure and subgrade reaction acted on the outer wall of the pipe joint; applying a winkler foundation module, regarding the loop strain calculation as the plane strain problem; analyzing the loop stress and deformation of the pipe joint structure by a load-structure method; through the calculation of cross model stress of the pipe joint, acquiring the relationship of the loop stress strain relationship of the pipe joint; finally, through calculation, acquiring the loop strain distribution of inner and outer walls of the pipe joint under one tide level and influence of the loop strain of every point of inner and outer walls of the pipe joint along with the change of the tide level. The calculation result can be used for predicting the loop strain of the pipe joint of the sinking pipe tunnel in operation stage, judging the part where may generate crack, and carrying out key monitoring and prevention.

The invention relates to a pipeline leakage and corrosion online monitoring device and method based on optical fiber grating sensing. The device comprises a beam splitting system, a demodulating system, a control system and optical fiber grating sensors which are fixed on the outer wall of a long straight pipeline and the outer wall of a bent pipe. The optical fiber grating sensors fixed on the outer wall of the long straight pipeline only have one optical fiber grating and are arranged axially at equal intervals, and judge whether the long straight pipeline leaks or not according to a change condition of detected hoop strain of the pipeline, find out the leak position and acquire uniform corrosion condition; and the optical fiber grating sensors fixed on the outer wall of the long straight pipeline are provided with a plurality of optical fiber gratings and the optical fiber gratings on the same optical fiber grating sensor are uniformly arranged along the circumference, and the optical fiber grating sensors judge non-uniform corrosion condition at the bent pipe according to a change condition of detected local hoop strain. The device is simple in structure, low in cost, convenient to mount and high in monitoring precision.