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Method for measuring large-strain compression hardening curve of metal hyperbolic curve sample

A technology of hardening curve and measurement method, which can be used in measurement devices, using stable tension/pressure to test the strength of materials, instruments, etc., which can solve problems such as huge iterative calculations.

Active Publication Date: 2020-05-22
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reverse deduction method often requires a large number of finite elements, the amount of iterative calculation is very large, and it requires experimenters to have a certain understanding of specific software, which is difficult to be widely used.

Method used

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  • Method for measuring large-strain compression hardening curve of metal hyperbolic curve sample
  • Method for measuring large-strain compression hardening curve of metal hyperbolic curve sample
  • Method for measuring large-strain compression hardening curve of metal hyperbolic curve sample

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] (1) The present invention takes the hyperbolic profile sample made of Q345 low carbon steel as an example to explain the specific implementation steps of the present invention in detail. Hyperbolic sample initial height h 0 is 20mm, the initial radius a of the smallest section in the middle 0 3mm, the specific structure is as figure 1 shown. Firstly, the compression experiment is carried out, the compression speed is 0.5mm / min, the load P borne by the metal material during the compression process, the height h of the sample and the radius a of the smallest section in the middle are recorded through the force sensor and the video extensometer, and respectively drawn as figure 2 The load-displacement curve of and such as Figure 4 The Δh / a-true strain curve. Finally, the average true stress-true strain is calculated by formulas (1) and (2), such as Figure 7 shown.

[0035]

[0036]

[0037] Δh=h 0 -h (3)

[0038] Among them, ε av , σ av are the average t...

Embodiment 2

[0052] (1) The present invention takes the hyperbolic profile sample made of AA1060 aluminum as an example to explain the specific implementation steps of the present invention in detail. Hyperbolic sample initial height h 0 is 20mm, the minimum initial radius of the middle section is a 0 3mm, specifically as figure 1 shown. First, carry out the compression experiment, the compression speed is 0.5mm / min, record the load P borne by the metal material during the compression process, the height h of the sample and the size of the radius a of the smallest section in the middle through the force sensor and video extensometer, and draw them respectively Such as image 3 The load-displacement curve of and such as Figure 5 The Δh / a-true strain curve. Finally, the average true stress-true strain curve is calculated by formulas (1) and (2), as Figure 8 shown.

[0053]

[0054]

[0055] Δh=h 0 -h (3)

[0056] Among them, ε av , σ av are the average true strain and aver...

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Abstract

The invention discloses a method for measuring a large-strain compression hardening curve of a metal hyperbolic curve sample. The invention belongs to the technical field of metal material mechanicalproperty testing. According to the method, a variable quantity of the radius of a minimum section of a hyperbolic curve sample in the compression process and a borne load are measured, and then a correction formula is utilized to acquire a corrected stress-strain curve. A corrected simulated load displacement curve and a corrected test load displacement curve are well overlapped, and a maximum error rate does not exceed 5%. According to the method, errors caused by drum shapes due to friction when existing compression tests are large in strain are avoided, an accurate stress-strain curve can be obtained, and the method has important significance in testing the mechanical properties of metal materials.

Description

technical field [0001] The invention belongs to the technical field of metal material mechanical performance testing, and is especially suitable for obtaining accurate stress-strain curves through compression experiments. Background technique [0002] In order to reduce production costs and improve production efficiency, finite element numerical simulation has been widely used in the field of metal plastic forming. As a prerequisite for numerical simulation, accurate material stress-strain curves have a crucial impact on the simulation results. Since metals are mainly in a state of compressive stress during the forming process, and metals can often achieve greater plastic deformation in compression tests, it is of great significance to obtain a wide range of stress-strain curves in compression tests. [0003] At present, the compressive stress-strain curve of metal materials is generally obtained through a single compression test of a cylindrical sample, but the friction be...

Claims

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Application Information

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IPC IPC(8): G01N3/08
CPCG01N3/08G01N2203/0003G01N2203/0019G01N2203/0075G01N2203/0216G01N2203/0218G01N2203/0262G01N2203/0641G01N2203/0676G01N2203/0682
Inventor 管志平邢敬升高丹任明文马品奎王慧远王珵管晓芳
Owner JILIN UNIV