Method, device and storage medium for correcting load of metal material compression test

Abstract

The present application relates to a kind of metal material compression test load correction method, equipment and storage medium, belong to metal material compression mechanical property test technical field.The correction method of the present application includes the following steps: obtaining the stiffness flexible deformation displacement of the flat anvil of testing machine generated in compression test of the metal material test piece to be measured, the flat anvil stiffness flexible deformation displacement obtained is substituted into the flat anvil stiffness flexible deformation displacement-load mathematical model of testing machine to obtain the load generated by flat anvil stiffness flexible deformation displacement, then the load directly extracted in compression test is subtracted according to the load calculated by model, to obtain the actual load of metal material test piece in compression test;Mathematical model is the relationship curve obtained by fitting the flat anvil stiffness flexible deformation displacement data and corresponding load data when the surface contact of upper and lower flat anvil on testing machine is carried out without sample feeding.The method can correct the data error caused by the stiffness flexible of flat anvil of testing machine in the process of metal sample compression test.

Description

Technical Field

[0001] This invention relates to a method, equipment, and storage medium for correcting the compression test load of metallic materials, belonging to the technical field of testing the compressive mechanical properties of metallic materials. Background Technology

[0002] Mechanical properties are important performance indicators of metallic materials, typically obtained through compression or tensile testing. According to the national standard for uniaxial tensile testing, an extensometer is usually used to measure the actual deformation of the specimen during tensile testing. In uniaxial compression testing, especially when the specimen height is small, it is impossible to measure the compression amount using an extensometer. Therefore, the specimen is usually placed between the upper and lower anvils of the testing machine, and the compression test is completed by moving the upper anvil. In data extraction, the displacement of the upper anvil on the testing machine is used as the actual compression amount of the specimen. Because the upper anvil itself has a certain degree of stiffness and flexibility, especially for specimens with high compressive strength, there is a certain amount of stiffness and flexibility deformation on the upper anvil before the specimen experiences true strain. This deformation is accumulated and calculated into the total compressive deformation of the specimen. In other words, the total deformation of the specimen includes not only the actual compressive deformation of the specimen itself but also the stiffness and flexibility deformation of the upper anvil itself. If the stiffness and flexibility deformation of the upper anvil is not corrected during the calculation, it will introduce a certain deviation in the calculation of the specimen's compressive mechanical properties. Summary of the Invention

[0003] The purpose of this invention is to provide a method for correcting the load in a compression test of metallic materials, which can correct data errors caused by the stiffness and flexibility of the anvil of the testing machine during the compression test of metallic material specimens.

[0004] The present invention also provides a computer device and a computer-readable storage medium.

[0005] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0006] A method for correcting the load in a compression test of metallic materials includes the following steps: acquiring the stiffness-flexibility deformation displacement generated by the anvil of the testing machine during the compression test of the metallic material specimen; substituting the acquired anvil stiffness-flexibility deformation displacement into the mathematical model of the testing machine anvil stiffness-flexibility deformation displacement-load to obtain the load generated by the anvil stiffness-flexibility deformation displacement; and then subtracting the load generated by the obtained anvil stiffness-flexibility deformation displacement from the load directly extracted in the compression test to obtain the actual load of the metallic material specimen in the compression test; the mathematical model is a relationship curve obtained by fitting the anvil stiffness-flexibility deformation displacement data and the corresponding load data when the upper and lower anvil surfaces of the testing machine are in contact without specimen feeding.

[0007] The method for correcting the compression test load of metallic materials according to the present invention can correct the data error caused by the stiffness and flexibility of the anvil of the testing machine during the compression test of metallic material specimens, and provide a reliable measurement means for accurately measuring the compressive mechanical properties of metallic materials.

[0008] It is understood that the load directly extracted in the compression test of this invention refers to the load corresponding to the stroke deformation displacement directly read from the testing machine, ignoring the stiffness-flexible deformation displacement generated by the anvil. The shape of the metal material specimen to be tested can be cylindrical, square, or annular. To avoid instability of the specimen during compression, the diameter-to-height ratio of cylindrical or annular metal material specimens should be within 1 / 3. To ensure uniform compression of the metal specimen, the end faces of the metal specimen that contact the upper and lower anvils of the testing machine must be kept parallel.

[0009] The method for constructing the mathematical model includes the following steps: setting a series of downward displacement values ​​for the testing machine; contacting the upper and lower anvil surfaces of the testing machine at each set downward displacement value; performing a sample-free feed; obtaining the stiffness-flexibility deformation and corresponding load of the testing machine anvil at the corresponding downward displacement value; and then performing data fitting based on these anvil stiffness-flexibility deformation displacement data and corresponding load data to obtain the mathematical model of the testing machine anvil stiffness-flexibility deformation displacement-load. When constructing the mathematical model, since the testing machine anvil exhibits stiffness-flexibility deformation, the downward displacement value of the testing machine is set to the stiffness-flexibility deformation displacement of the anvil during the current sample-free feed.

[0010] Furthermore, the stiffness-flexibility deformation displacement generated by the anvil in the compression test of the metal material specimen is obtained by subtracting the actual deformation displacement of the metal material specimen after compression deformation from the downward displacement of the testing machine.

[0011] A computer device includes a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program to implement the above-described method for correcting the compression test load of metallic materials.

[0012] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for correcting the compression test load of metallic materials.

[0013] The computer device of the present invention stores in its memory and computer-readable storage medium the present invention a method for correcting the compression test load of metallic materials when executed by a processor, which can correct data errors caused by the stiffness and flexibility of the anvil of the testing machine during the compression test of metallic material specimens. Attached Figure Description

[0014] Figure 1This is a graph showing the relationship between the stiffness, flexibility, deformation, displacement, and load of the testing machine's anvil in Example 1.

[0015] Figure 2 Displacement-load curves of TA18 titanium alloy specimens before and after compression correction;

[0016] Figure 3 The stress-strain curves of the TA18 titanium alloy specimen before and after compression correction are shown. Detailed Implementation

[0017] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0018] Example 1

[0019] The method for correcting the compression test load of metallic materials in this embodiment includes the following steps:

[0020] 1) A general-purpose testing machine was used to perform compression tests on cylindrical metal specimens with compression displacements of 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm and 9mm respectively. After each compression test, the height of the compressed specimen was measured and the corresponding load was directly extracted. At the same time, the corresponding stroke displacement recorded by the testing machine was recorded.

[0021] The metal material specimen used was an initial TA18 titanium alloy tube with a wall thickness of 0.9 mm, a diameter of 12 mm, and a height of 10 mm. The two ends of the specimen were parallel, smooth, and perpendicular to the specimen axis, so that the specimen could be uniformly compressed.

[0022] 2) The stroke displacement recorded by the testing machine includes the stiffness-flexibility deformation displacement of the anvil and the actual displacement after the specimen is compressed. By subtracting the actual deformation after the specimen is compressed from the stroke displacement recorded by the testing machine in each compression test, the stiffness-flexibility deformation displacement generated by the anvil during the specimen compression process in the corresponding compression test can be obtained. Based on this, the stiffness-flexibility deformation displacement generated by the anvil in each compression test in step 1) can be calculated.

[0023] 3) Set the compression amount of the testing machine to the stiffness-flexibility deformation displacement generated by the anvil in each compression test calculated in step 2), and put the upper and lower anvils of the testing machine into contact to perform compression feed without specimen, and record the load under each displacement.

[0024] 4) Perform data fitting on the stiffness-flexibility deformation displacement data generated by the anvil in step 3) and the corresponding load data to obtain the mathematical model of the anvil stiffness-flexibility deformation displacement-load as shown in formula (1). Figure 1 As shown. Figure 1The curves of the experimental data are obtained by plotting the stiffness, flexibility, deformation, displacement of the anvil and its corresponding load.

[0025]

[0026] In the formula, F is the load generated by the stiffness-flexible deformation displacement of the anvil, and X is the stiffness-flexible deformation displacement of the anvil.

[0027] 5) Place the metal material sample to be tested in the testing machine for compression test, obtain the stroke displacement through the testing machine and extract the load; after the compression test, measure the height of the metal material sample to be tested after compression, calculate the actual deformation based on the measured height value, and then subtract the actual deformation from the obtained stroke displacement to obtain the stiffness-flexibility deformation displacement generated by the anvil during the compression process of the sample. Substitute the obtained stiffness-flexibility deformation displacement generated by the anvil into formula (1) to obtain the load generated by the stiffness-flexibility deformation displacement of the anvil. Then subtract the load directly extracted from the stroke displacement recorded by the testing machine from the calculated load generated by the stiffness-flexibility deformation displacement of the anvil to calculate the actual load of the metal sample to be tested, thereby correcting the load error caused by the stiffness-flexibility of the testing machine, and thus accurately obtaining the actual load of the sample in compression deformation, and obtaining the actual displacement based on the actual deformation.

[0028] Using TA18 titanium alloy tubes with a wall thickness of 0.9 mm, a diameter of 12 mm, and a height of 10 mm as the metal material samples to be tested, compression tests were conducted on multiple TA18 titanium alloy tube samples according to step 5). The actual displacement and actual load of each compression test metal material specimen were obtained. Then, based on the actual displacement and actual load, corrected displacement-load curves and stress-strain curves were plotted. At the same time, based on the load extracted and the recorded stroke displacement from each compression test in step 1) of Example 1, uncorrected displacement-load curves and stress-strain curves were plotted. The displacement-load curves and stress-strain curves before and after correction were compared respectively. Figure 2 and Figure 3 As shown.

[0029] The method for correcting the compression test load of metallic materials according to the present invention is applicable to the mechanical property testing of materials under compression deformation without an extensometer. It can correct for errors in stiffness and flexibility displacement that are unavoidable in testing machines. Experimental verification has shown its feasibility, and it can, to a certain extent, solve the stiffness error generated by the testing machine itself, improve the accuracy of material compression mechanical property data, and facilitate the accurate determination of the compression deformation performance of metallic materials.

[0030] Example 2

[0031] The computer device of this embodiment includes a processor and a memory; the memory is used to store computer programs, and the processor is used to execute the computer programs to implement the method in step 5) of the above embodiment 1, which is "to calculate the actual deformation based on the measured height value, and then subtract the actual deformation from the obtained stroke displacement to obtain the stiffness-flexibility deformation displacement generated by the anvil during the sample compression process, and substitute the obtained stiffness-flexibility deformation displacement generated by the anvil into formula (1) to obtain the load generated by the stiffness-flexibility deformation displacement of the anvil, and then subtract the load directly extracted from the stroke displacement recorded by the testing machine from the calculated load generated by the stiffness-flexibility deformation displacement of the anvil to calculate the actual load of the metal sample to be tested".

[0032] Example 3

[0033] The computer-readable storage medium of this embodiment stores a computer program. When the computer program is executed by a processor, it implements step 5) of embodiment 1 above, which involves "calculating the actual deformation based on the measured height value, then subtracting the actual deformation from the obtained stroke displacement to obtain the stiffness-flexibility deformation displacement generated by the anvil during the sample compression process, substituting the obtained stiffness-flexibility deformation displacement generated by the anvil into formula (1) to obtain the load generated by the stiffness-flexibility deformation displacement of the anvil, and then subtracting the load directly extracted from the stroke displacement recorded by the testing machine from the calculated load generated by the stiffness-flexibility deformation displacement of the anvil to calculate the actual load of the metal sample to be tested." The computer-readable storage medium mentioned here includes random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art.

Claims

1. A method for correcting the compression test load of metallic materials, characterized in that: Includes the following steps: The stiffness-flexibility deformation displacement generated by the anvil of the testing machine during the compression test of the metal material specimen is obtained. This obtained stiffness-flexibility deformation displacement is then substituted into the mathematical model of the stiffness-flexibility deformation displacement-load of the testing machine to obtain the load generated by the stiffness-flexibility deformation displacement of the anvil. Finally, the load generated by the obtained stiffness-flexibility deformation displacement of the anvil is subtracted from the load directly extracted from the compression test to obtain the actual load of the metal material specimen in the compression test. The stiffness-flexibility deformation displacement generated by the anvil in the compression test of the metal material specimen is obtained by subtracting the actual deformation displacement of the metal material specimen after compression deformation from the downward displacement of the testing machine. The mathematical model is a relationship curve obtained by fitting the anvil stiffness, flexibility, deformation, and displacement data with the corresponding load data when the upper and lower anvil surfaces of the testing machine are in contact without sample feeding.

2. The method for correcting the compression test load of metallic materials according to claim 1, characterized in that: Metal specimens are used in contact testing machines where the end faces of the upper and lower anvils are kept parallel.

3. A computer device, characterized in that: The computer device includes a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program to implement the method for correcting the compression test load of metallic materials as described in claim 1 or 2.

4. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method for correcting the compression test load of metallic materials as described in claim 1 or 2.

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