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Device for testing bending fatigue of oil casing under complex load

A composite load and bending fatigue technology, which is applied in the direction of testing the strength of materials by applying a stable bending force, can solve problems such as fatigue, and achieve the effect of reducing performance requirements

Active Publication Date: 2014-07-16
西安三维应力工程技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The bending moment of this device is always in one direction during the test, such as Figure 7 As shown, only the size changes, and the bending moment at the rubber bearing 6 also produces cyclic changes, plus wear and tear, which is more prone to fatigue

Method used

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  • Device for testing bending fatigue of oil casing under complex load
  • Device for testing bending fatigue of oil casing under complex load
  • Device for testing bending fatigue of oil casing under complex load

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0023] Embodiment: the concrete operating steps of the present invention are:

[0024] 1) Determine the mass of the bending load weight 2 according to the size of the sample 7;

[0025] 2) If there is no internal pressure and axial load, press figure 2 The first-order bending natural frequency of the structural analysis shown;

[0026] 3) Adjust the power supply change frequency of the control power supply according to 3 / 5 of the frequency calculated in the second step, and drive the sample to rotate;

[0027] 4) Monitor the change of bending displacement until it is stable;

[0028] 5) If the bending displacement cannot reach the required value after stabilization, gradually increase the motor speed and monitor the change of displacement;

[0029] 6) When the bending displacement reaches the required value, stabilize the rotation speed and start the rotation bending fatigue test;

[0030] 7) When the sample undergoes fatigue fracture or the number of cycles reaches the r...

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PUM

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Abstract

The invention relates to a device for testing bending fatigue of an oil casing under a complex load. The conventional device has extremely high requirement on fatigue resistance of a test system, a sample often fails when not fatigued and existing bolts and other accessories of test equipment are fractured due to fatigue. The device for testing bending fatigue of the oil casing under the complex load comprises a loading part and a supporting part, wherein the loading part comprises a sample and two sample plugs positioned at two ends of the sample; the supporting part comprises two rubber supports positioned below the sample plugs; a bent loading weight is arranged at the end on the outer side of each sample plug. The device can simulate and evaluate fatigue strength of a drill stem under the rotating and bending action and also can simulate the strength and sealing reliability of the oil casing under the cyclic bending load action, an axial load can be applied to a pipe or a rotating shaft, and the bending fatigue life of a structural part in a complex stress state is simulated. Moreover, a sample is electromagnetically driven to rotate and bend, and the performance requirement of a test on a testing mechanical structure is met.

Description

technical field [0001] The invention belongs to the technical field of drilling, and relates to a bending fatigue test device for an oil casing under composite load. Background technique [0002] At present, in the process of oil and gas development, in order to ensure that the drill pipe does not experience abnormal fatigue fracture during the downhole drilling process, it is required to conduct a rotating bending fatigue life test evaluation on the ground. For casing and tubing, under the conditions of various factors such as temperature and high-pressure fluid movement and impact in the downhole, chattering often occurs. Under the action of vibration, the oil casing undergoes cyclic bending response. Long-term bending leads to failure accidents such as bending fatigue fracture of the tubing and casing in the downhole, or leakage at the joint. At present, there is no suitable test device that can simulate the oil casing under such working conditions. It only has th...

Claims

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Application Information

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IPC IPC(8): G01N3/20
Inventor 杨析申昭熙史交齐
Owner 西安三维应力工程技术有限公司
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