DIC-based Bauschinger effect test sample, fixture and method

A Bauschinger effect and test fixture technology, applied in measuring devices, instruments, scientific instruments, etc., can solve problems such as easy instability, and achieve the effects of small deformation area, high test efficiency and uniform deformation

Inactive Publication Date: 2019-03-29
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a kind of Bauschinger effect test sample, fixture and method based on DIC, solve the problem that the thin-walled plate / pipe material sample in the prior art is easy to lose stability in the test

Method used

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  • DIC-based Bauschinger effect test sample, fixture and method
  • DIC-based Bauschinger effect test sample, fixture and method
  • DIC-based Bauschinger effect test sample, fixture and method

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Such as figure 1 As shown, a kind of Bauschinger effect test sample based on DIC comprises a connecting body 12 and two sample bodies 11 arranged symmetrically, the two sample bodies 11 are connected through the connecting body 12, and the two Holes 13 are provided on each of the sample bodies 11, and the sample bodies 11 are in the shape of a semicircle.

[0035] Specifically, the length of the sample body 11 is 30mm, the outer diameter is 12mm, and the thickness is 1.9mm, the length of the connecting body 12 is 3.9-4.1mm, the width is 1.9-2.1mm, and the diameter of the opening 13 is 6mm. .

[0036] The small gauge sample 1 used in the DIC-based Bauschinger effect test sample in Example 1 is smaller than the critical instability wavelength in a low stress state, so the critical instability force can be delayed without lateral restraint The generation of (critical instability point) can obtain more objective compressive strain, the deformation area is small, the defor...

Embodiment 2

[0038] Such as Figure 2 to Figure 5 Shown, a kind of Bauschinger effect test fixture based on DIC comprises first fixture 2, second fixture 4 and pin 3, and described first fixture 2 is rectangular parallelepiped and middle part is provided with semicircular groove longitudinally, and described half The longitudinal middle part of the circular groove is provided with a first matching hole, the second fixture 4 is a cuboid and the middle part is longitudinally fixed with a protrusion, and the longitudinal middle part of the protrusion is provided with a second matching hole, and the pin 3 is sequentially connected with the first fitting hole. A matching hole and the second matching hole are matched and connected, and the protrusion of the second clamp 4 presses and fixes the sample 1 in the semicircular groove of the first clamp 2 .

[0039] Specifically, the first fixture 2 is 44mm long, 30mm wide, and 10mm high, and the radius of the semicircular groove is 6mm. The second fi...

Embodiment 3

[0043]Such as Figure 6 As shown, a method for testing the Bauschinger effect based on DIC, using the described Bauschinger effect test fixture based on DIC to test the sample 1, the specific steps are as follows:

[0044] Step 1, making small gauge sample 1: for thin-walled tube blanks, process the tube blanks into small gauge sample 1 by wire cutting according to the size;

[0045] Step 2, speckle production and clamping of sample 1: first uniformly spray a layer of white paint on the gauge section of sample 1, and after the paint is dry, spray uneven black spot-like paint to make speckle sample 1, And clamp the sample 1 on the test fixture;

[0046] Step 3, digital speckle system calibration: turn on the electronic universal testing machine and digital speckle system, set the focal length in the focal plane where sample 1 is located, adjust the aperture size to obtain a clear speckle picture, and then use the calibration board to carry out Calibration of the digital speck...

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Abstract

The invention discloses a DIC-based Bauschinger effect test sample, fixture and method. First, a tube blank is processed into a small gauge-length sample by wire cutting according to the size; a layerof white paint is uniformly sprayed at a sample gauge-length section; after the paint is dried, uneven black spotted paint is sprayed, a speckle sample is manufactured, and the sample is clamped on the test fixture; an electronic universal test machine and a digital speckle system are opened to set focal length to a focal plane where the sample is located, the aperture size is adjusted to obtaina clear speckle picture, then, a calibration plate is used to calibrate the digital speckle system under the condition; a tensile test under different pre-compressed strain conditions is carried out;and the test data is analyzed to obtain a Bauschinger effect of the material. The small gauge-length sample used in the invention has small deformation area and uniform deformation, and can realize tensile compression stress reverse loading. The test method can efficiently and accurately determine the Bauschinger effect of the thin wall plate/tube material.

Description

technical field [0001] The invention relates to the technical field of plastic forming of metal materials, in particular to a DIC-based Bauschinger effect test sample, fixture and method. Background technique [0002] The Bauschinger effect is a mechanical property of metal materials. It is manifested that when the material is subjected to a load in a certain direction (such as stretching) and enters the plastic deformation stage, if a load in the opposite direction (such as compression) is then applied, it will be found that At this time, the yield stress of the material will be lower than that when the latter load is applied directly. In the process of material processing, different loading processes may be experienced, such as stretching, bending, straightening and reverse bending. For such processes with complex stress situations, the Bauschinger effect can have a significant impact on the prediction results of the finite element model. [0003] Common experimental met...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/04G01N3/02
CPCG01N3/02G01N3/04G01N2203/0017G01N2203/0423
Inventor 李恒马俊杨恒贺子芮刘浩然黄卫良
Owner NORTHWESTERN POLYTECHNICAL UNIV
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