Method and apparatus for mechanical fixation of dynamic extensometer in high temperature fatigue test

A fatigue test and extensometer technology, used in measuring devices, instruments, scientific instruments, etc., can solve the problems of inability to observe the high temperature corrosion morphology of the sample surface, affecting the accuracy of high temperature fatigue test results, and having certain requirements for operating temperature. , to achieve the effect of good plasticity, low cost and low price

Active Publication Date: 2016-01-06
NANJING UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, most high-temperature coatings are obtained by mixing silicates and other ingredients in a certain ratio, which has certain requirements on the use temperature, and is very brittle under high temperature conditions, and is easy to break and fall off during the test
In addition, high-temperature coatings are not only cumbersome to prepare, cannot be reused repeatedly, and have a long curing time, but also the coating on the surface of the sample hinders the surface oxidation of the sample under high-temperature conditions, which seriously affects the accuracy of the high-temperature fatigue test results and cannot be observed. The high-temperature corrosion morphology of the sample surface after the test

Method used

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  • Method and apparatus for mechanical fixation of dynamic extensometer in high temperature fatigue test
  • Method and apparatus for mechanical fixation of dynamic extensometer in high temperature fatigue test
  • Method and apparatus for mechanical fixation of dynamic extensometer in high temperature fatigue test

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Effect test

Embodiment 1

[0040] High temperature fatigue test with strain control mode, the radius R of the parallel section of the fatigue sample is 5mm, and the gauge length L of the dynamic extensometer for measuring the deformation of the fatigue sample 4 is 25mm.

[0041] 1) Select a thin stainless steel plate with a thickness of δ=0.5mm, and symmetrically process the diameter d=3mm on the thin plate, and the hole distance L 1 = Two screw holes of 31.4mm;

[0042] 2) Using wire cutting technology, process the thin plate in step 1 into a rectangle with a width of W=5mm and a length of L=50mm, and the center of symmetry of the rectangle coincides with the center of symmetry of the two screw holes, as figure 1 shown, and grind the roughness of one of the two surfaces of the thin plate to Ra0.2 with a length of 50mm and a width of 5mm;

[0043] 3) Fit the surface of the polished thin plate to the surface of the sample, take the cylinder in the parallel section of the fatigue sample as the standard,...

Embodiment 2

[0049] High-temperature fatigue test under complex load with strain-stress compound control method, the radius R of the parallel section of the fatigue sample is 3 mm, and the gauge length L of the dynamic extensometer for measuring the deformation of the fatigue sample 4 is 12.5mm.

[0050] 1) Select a thin stainless steel plate with a thickness of δ=0.5mm, and symmetrically process the diameter d=2.5mm on the thin plate, and the hole distance L 1 = Two screw holes of 18.8mm;

[0051] 2) Using wire cutting technology, process the thin plate in step 1 into a rectangle with a width of W=4mm and a length of L=37mm. The center of symmetry of the rectangle coincides with the center of symmetry of the two screw holes, as figure 1 shown, and grind the roughness of one of the two surfaces of the thin plate with a length of 37mm and a width of 4mm to Ra0.2;

[0052] 3) Fit the surface of the polished thin plate to the surface of the sample, take the cylinder in the parallel section ...

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Abstract

The invention discloses a method and apparatus for mechanical fixation of a dynamic extensometer in a high temperature fatigue test. According to the method, two U-shaped plates with specially-produced V-shaped grooves are fixed on the surface of a fatigue test piece through fastening screws and the front end of the high temperature dynamic extensometer is embedded into the two V-shaped grooves, so sliding of the dynamic extensometer in the process of fatigue testing is avoided. The apparatus is mainly composed of thin plates and the fastening screws, wherein the thin plates are equipped with the specially-produced V-shaped grooves. The apparatus is simple in structure and easy in processing. According to the invention, on the basis that the surface morphology of the fatigue test piece is not changed, sliding of the dynamic extensometer in the process of high temperature fatigue testing is effectively avoided, deformation of the test piece in the process of fatigue testing is accurately measured, and smooth implementation of fatigue testing is guaranteed; and the apparatus has the characteristics of good versatility, simple operation, easiness in processing and repeated usability.

Description

technical field [0001] The invention belongs to material testing, in particular to a method and device for mechanically fixing a dynamic extensometer in a high-temperature fatigue test. Background technique [0002] As one of the most typical failure forms of metal structures, fatigue failure has become the core subject of mechanical structures since the 1920s and 1930s. The main research directions focus on metal fatigue crack growth, fatigue damage mechanism and fatigue life. predictive models, etc. At present, the fatigue damage and life analysis of materials based on the fatigue test results measured in the laboratory are the most important and basic research methods. The control methods of fatigue test mainly include stress control, strain control and stress-strain composite control. According to the needs of researchers, most fatigue tests need to measure the deformation value of the sample, especially for the fatigue test of the strain control method, the accurate m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/02
Inventor 王小威巩建鸣姜勇王艳飞郁明浩
Owner NANJING UNIV OF TECH
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