Real-time measuring apparatus and real-time measuring method for large deformation and stress of test tube in steel pipe bending deformation

Abstract

The invention discloses a real-time measuring apparatus and a real-time measuring method for large deformation and stress of a test tube in steel pipe bending deformation. The measuring apparatus comprises an oil cylinder, a hydraulic system, a pressure sensor, a water pressure system, a movable side force arm, the test tube, a strain meter, a rotation-angle measuring apparatus for a 2D length position at the middle of the test tube, a transition ring, a connecting flange, a fixed side force arm, a rotation-angle measuring apparatus for a tube end of the test tube, an adjusting joint, a load-bearing beam, a control system, a computer data acquisition and processing system, a stress and strain measurement system and a draw-wire displacement sensor III. The apparatus can increase measuring stability and measuring accuracy. The measuring method realizes automatic control, real-time supervision and automatic measurement of a steel pipe bending deformation test, can fully monitor and record changes of load, displacement, rotation angle, distribution of the stress and the strain when the test tube occurs bending deformation while bearing internal pressure load and bending load at the same time, can acquire, record and display test data in time, and can analyze and treat the test data.

Description

technical field [0001] The invention relates to the field of petroleum pipeline engineering, in particular to a real-time measuring device and a measuring method for large deformation and stress of test pipes during bending deformation of steel pipes. Background technique [0002] Steel pipe bending deformation test is to simulate the actual service load of the oil and gas delivery pipe, measure the test pipe's load and displacement relationship, load and rotation angle relationship, test pipe stress and strain distribution, etc. when the test pipe is bent and deformed, and determine the buckling of the test pipe. The strain limit for instability. Evaluate the resistance to buckling deformation of steel pipes under bending loads. [0003] At present, the institutions that realize the steel pipe bending deformation test include the British Welding Institute TWI, the Canadian C-FER company and other research institutions. Among them, TWI's whole pipe bending test system adop...

AI Technical Summary

Problems solved by technology

The former has the advantages of large load and strong test ability, but the test form of four-point bending is easy to cause local deformation of the steel pipe

Although the latter does not have the problem of local deformation, because the test equipment is limited by the space of the large tensile machine, the test tube is too short, it is difficult to apply sufficient bending moment, and it often has a strong axial compression load

[0004] In the process of realizing the present invention, the inventor found that the prior art has at least the following problems: none of the existing equipment and methods can obtain ideal bending deformation test conditions

Moreover, when the steel pipe is bent and deformed, the deformation of the test pipe and the stress-strain distribution of the test pipe cannot be obtained in time, so it is difficult to determine the strain limit of the test pipe when it buckles and loses stability.

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