A test specimen and test device for uniaxial in-plane compression test of thin plate material at high temperature

Abstract

The present invention provides a specimen and a test device for uniaxial in-plane compression test of thin plate materials at high temperature, wherein the specimen is a dog-bone-shaped specimen, wherein the parallel section in the middle of the specimen includes a groove located on the front side surface and transition zones located on the upper and lower ends of the groove; the test device adopts the specimen and also includes a clamp; the clamp includes a front anti-buckling plate and a rear anti-buckling plate, and the specimen is clamped between the front anti-buckling plate and the rear anti-buckling plate; the front anti-buckling plate is installed on the rear anti-buckling plate through a guide pin and a spring clamping device, and the spring clamping device includes a butterfly spring washer assembly; the front anti-buckling plate is provided with a positioning pin for limiting the left and right sides of the specimen. The operation of in-plane compression test using the specimen and the test device provided by the present invention is simple, and can improve the test accuracy and the maximum measurable compression strain.

Description

Technical Field

[0001] The present invention relates to the technical field of material mechanical property testing, and in particular to a test specimen and a test device for a uniaxial in-plane compression test of a thin plate material at high temperature. Background Art

[0002] Due to the tension-compression asymmetry and Bauschinger effect of many lightweight materials, the characterization of the mechanical properties of materials under compressive loads has received increasing attention. Tension-compression asymmetry is a significant constitutive behavior of hexagonal close-packed (HCP) metals, porous materials, and carbon fiber reinforced composites. The Bauschinger effect is a ubiquitous phenomenon in most polycrystalline metals. During sheet forming and impact processes, part of the material fibers that are delaminated along the thickness direction of the sheet are usually inevitably subjected to in-plane compression or cyclic tension-compression. Therefore, it is crucial to develop a test method to characterize the mechanical properties of materials under monotonic compression or cyclic tension-compression in the plane. However, it has long been a challenge to determine the compressive properties of thin sheet materials because thin sheet materials tend to buckle before true compressive failure occurs when compressive loads are applied.

[0003] In in-plane compression tests, large slenderness ratios and eccentric loading of thin plate specimens may cause specimen buckling, leading to premature failure of the specimen. In addition to buckling, small slenderness ratios and inappropriate boundary constraints may cause specimen barreling, resulting in uneven strain distribution and non-uniaxial stress state. Therefore, a reliable in-plane compression test method should be able to suppress specimen buckling and barreling. In order to meet these criteria, various in-plane compression test methods for thin plates, plastics, and composites have been developed. According to the load application method and specimen geometry, the methods can be divided into three categories: shear loading method, end loading method, and combined loading method.

[0004] The shear loading method introduces the load into the specimen through the shearing action of the fixture, while the end loading method introduces the load through the two end faces of the specimen, and the composite loading compression method integrates the advantages of the first two methods. These three methods have been used in different test standards. For plastics, ASTM D695 adopts the end loading method; for composite materials, ASTM D3410, Boeing's modified ASTM D695 and ASTM D6641 respectively adopt the above three methods; for metals, the room temperature test standard ASTME9 and the high temperature test standard ASTM E209 respectively adopt the shear loading and end loading methods. Since the shear loading method has good compatibility with tensile tests, it is usually used in cyclic tension-compression tests.

[0005] According to the geometry of the specimen, two main types of test methods are proposed. The first is called the stacking method, proposed by Aitchison and Tuckerman, such as Figure 1As shown in (a), by bonding and stacking multiple thin plate layers, a smaller slenderness ratio can be obtained, thereby suppressing the buckling of the specimen. In recent years, this test method has been successfully applied to AZ31, ZE10 and ZEK100 magnesium alloys at high temperatures and high strain rates. Although this method can use digital image correlation technology (DIC) to measure strain, which is another major advantage of this method, the glue layer is easy to soften at high temperatures, and the specimen preparation is time-consuming and costly; in addition, due to the small slenderness ratio and the friction force at the end, the barrel effect is inevitable in large compression deformation. As shown in Figure 1 As shown in (b), the second test method is to use a single thin plate specimen of rectangular or dog-bone shape and use an anti-buckling fixture to apply lateral support to the wide surface of the specimen to prevent the specimen from bending in the thickness direction. This test method has been widely used in some in-plane monotonic compression test standards, such as ASTM D3410, Boeing modified ASTM D695, ASTM D6641, ASTM E9 and ASTM E209. However, in this test method, the maximum compressive strain that can be achieved before the specimen buckles is usually less than 0.1.

[0006] In the past two decades, due to the increasing demand for the study of the Bauschinger effect in sheet forming and impact processes, many innovative studies have been conducted to develop complex methods for continuous cyclic tension-compression testing under large strain conditions. Yoshida et al. used a different stacking method, in which five dog-bone specimens were bonded together and wide-side lateral supports were applied. This method measured compressive strains up to 0.25 for mild steel and 0.13 for high-strength steel, but this method has the same disadvantages as the stacking method. Boger et al. used a hydraulic clamping system with solid side plates to support enlarged dog-bone specimens under cyclic tension-compression loading conditions. This method was able to measure compressive strains up to 0.15 for aluminum alloys. However, the maximum compressive strain achievable by this method is highly dependent on the length of the unsupported section and the specimen and loading axis must be aligned, so this method may not be suitable for very thin specimens.

[0007] In order to eliminate the interference problem between the longitudinal platen and the transverse support fixture, Kuwabara et al. developed an integrated test device for continuous cyclic tension-compression based on a comb-shaped anti-buckling fixture. After using this method, even if the sample is very thin, a compressive strain of 0.15-0.20 can be measured. However, due to the size limitation of the comb-shaped anti-bending fixture, a longer sample is required, so it is difficult to ensure the centering of the loading axis and the sample axis; the misalignment of the centering leads to a decrease in the maximum compressive strain before buckling. The maximum compressive strain can be increased by increasing the clamping force, but the larger biaxial stress effect and friction effect will reduce the measurement accuracy. Using a similar principle, Cao et al. developed a new anti-buckling fixture that uses 4 wedges to cover the entire wide surface of the dog-bone-shaped specimen and can move freely with the sample during the test. This method can measure the maximum compressive strain of steel and aluminum alloy to be about 0.1.

[0008] It has always been difficult to measure strain using the second method because the anti-buckling device blocks the wide side of the specimen. Some common methods are to use foil strain gauges, laser extensometers, and DIC techniques to measure strain on the thick side of the specimen. However, these methods are not always feasible. For example, for very thin specimens, it is very difficult to use strain gauges or DIC measurement techniques.

[0009] In summary, the existing testing technology still cannot meet the increasing testing needs, and more effective testing methods are urgently needed, which can not only ensure more accurate strain measurement, but also achieve higher maximum compressive strain. Summary of the invention

[0010] Based on the above technical problems existing in the existing plate in-plane compression test method, a specimen and a device for uniaxial in-plane compression test of thin plate materials at high temperature are provided.

[0011] The technical means adopted by the present invention are as follows:

[0012] A specimen for uniaxial in-plane compression test of thin plate materials at high temperature is a dog-bone shaped specimen. The parallel section in the middle of the specimen comprises a groove located on the front side and transition zones located at the upper and lower ends of the groove.

[0013] Furthermore, the ratio of the groove length to the parallel section length is 1 / 3 to 3 / 4; the ratio of the groove depth to the thickness of the portion of the sample excluding the groove is 0.025 to 0.1.

[0014] The present invention also provides a uniaxial in-plane compression test device for thin plate materials at high temperatures, which uses the above-mentioned specimen and also includes a clamp; the clamp includes a front anti-buckling plate and a rear anti-buckling plate, and the specimen is clamped between the front anti-buckling plate and the rear anti-buckling plate; the front anti-buckling plate is installed on the rear anti-buckling plate through a guide pin and a spring clamping device, and the spring clamping device includes a butterfly spring washer assembly; the front anti-buckling plate is provided with positioning pins for limiting the left and right sides of the specimen.

[0015] Furthermore, the spring clamping device also includes a bolt and a nut, the bolt passes through the front anti-buckling plate and the rear anti-buckling plate and is fixed by the nut, and the butterfly spring washer assembly is sleeved on the bolt and located between the bolt head and the front anti-buckling plate.

[0016] Furthermore, the front anti-buckling plate includes a front upper anti-buckling plate and a front lower anti-buckling plate arranged at the top and bottom; the lower surface of the specimen is flush with the upper surface of the base; the front upper anti-buckling plate and the front lower anti-buckling plate are respectively installed on the rear anti-buckling plate through the guide pin and the spring clamping device.

[0017] Furthermore, the front upper anti-buckling plate and the front lower anti-buckling plate are respectively provided with two positioning pins.

[0018] Furthermore, the butterfly spring washer assembly includes a plurality of butterfly spring washers, and the stiffness coefficient and the maximum deformation of the butterfly spring washer assembly can be adjusted by adjusting the number and combination of the butterfly spring washers.

[0019] Furthermore, the front anti-buckling plate is provided with a data collection opening for exposing the groove.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The present invention provides a specimen for uniaxial in-plane compression test of thin plate materials at high temperature, and designs a new dog-bone-shaped specimen. A transition zone is respectively set at the upper and lower ends of the groove of the parallel section of the specimen. On the one hand, it can suppress the barrel effect in the measurement area of ​​the specimen, and on the other hand, it can also delay the buckling failure of the specimen, that is, increase the maximum measurable compression deformation, so as to achieve the goal of the maximum compression strain exceeding 0.2 before the specimen buckles.

[0022] 2. The uniaxial in-plane compression test device for thin plate materials at high temperature provided by the present invention is designed with an anti-buckling fixture that can allow the sample to expand or elongate along the thickness direction to suppress the buckling of the sample. The uniaxial in-plane compression test using the test device can achieve higher accuracy without the need for biaxial stress effect correction and friction effect correction.

[0023] Based on the above reasons, the present invention can be widely promoted in the field of material mechanical property testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 Schematic diagram of the principles of the two in-plane compression test methods described in the background technology.

[0026] Figure 2 Schematic diagram of the sample structure of the present invention.

[0027] Figure 3 It is an enlarged schematic diagram of the side of the groove structure.

[0028] Figure 4 It is a schematic diagram of the structure of the test device of the present invention.

[0029] Figure 5 It is a front schematic diagram of the test device of the present invention.

[0030] Figure 6 for Figure 5 Section view in AA direction.

[0031] Figure 7 for Figure 6 Enlarged view of part B in the middle.

[0032] Figure 8 It is a schematic diagram of the combination types of the butterfly spring washers described in the present invention.

[0033] In the figure: 1, pressure plate; 2, rear anti-buckling plate; 3, front upper anti-buckling plate; 4, front lower anti-buckling plate; 5, test specimen; 51, support section; 52, free section; 53, parallel section; 54, groove; 55, transition zone; 6, base; 7, guide pin; 8, high-temperature bushing; 9, bolt; 10, butterfly spring washer assembly; 11, positioning pin. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0037] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0038] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Without relevant explanations, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0039] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0040] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0041] Example 1

[0042] like Figure 2-3 As shown, the present invention provides a specimen for uniaxial in-plane compression test of thin plate materials at high temperature, wherein the specimen 5 is a dog-bone shaped specimen, and the parallel section 53 in the middle of the specimen 5 includes a groove 54 located on the front side and transition zones 55 located at the upper and lower ends of the groove 54.

[0043] Furthermore, the ratio of the length of the groove 54 to the length of the parallel section 53 is 1 / 3 to 3 / 4; the ratio of the depth of the groove 54 to the thickness of the portion of the sample 5 excluding the groove 54 is 0.025 to 0.1.

[0044] Furthermore, the connection between the transition zone 55 and the groove 54 may be a fillet or a right angle with a radius of R2, which is specifically determined by the tool selected during processing.

[0045] like Figure 4-7 As shown, the present invention also provides a uniaxial in-plane compression test device for thin plate materials at high temperature, adopts the above-mentioned sample 5, and also includes a clamp; the clamp includes a front anti-buckling plate and a rear anti-buckling plate 2, and the sample 5 is clamped between the front anti-buckling plate and the rear anti-buckling plate 2; the front anti-buckling plate is installed on the rear anti-buckling plate 2 through a φ5mm guide pin 7 and a spring clamping device, and the spring clamping device includes a butterfly spring washer assembly 10; the front anti-buckling plate is provided with a positioning pin 11 for limiting the left and right sides of the sample.

[0046] Furthermore, the spring clamping device also includes a bolt 9 and a nut, the bolt 9 passes through the front anti-buckling plate and the rear anti-buckling plate 2 and is fixed by the nut, and the butterfly spring washer assembly 10 is sleeved on the bolt 9 and located between the head of the bolt 9 and the front anti-buckling plate.

[0047] Furthermore, the front anti-buckling plate includes a front upper anti-buckling plate 3 and a front lower anti-buckling plate 4 which are arranged at the upper and lower parts; the lower surface of the specimen is flush with the upper surface of the base; the front upper anti-buckling plate 3 and the front lower anti-buckling plate 4 are respectively installed on the rear anti-buckling plate 2 through the guide pin 7 and the spring clamping device.

[0048] Furthermore, the front upper anti-buckling plate 3 and the front lower anti-buckling plate 4 are respectively provided with two φ2mm positioning pins 11 for limiting the left and right sides of the specimen 5 to ensure that the specimen 5 is located in the middle position of the fixture; the positioning pins 11 can play a role in rapid positioning. At the same time, the positioning pins 11 are used to ensure that the specimen 5 is located in the middle position of the fixture, which can further ensure that the longitudinal center line of the specimen 5 is consistent with the load center line, thereby eliminating the risk of eccentric load.

[0049] Furthermore, the butterfly spring washer assembly 10 includes a plurality of butterfly spring washers, and the stiffness coefficient and the maximum deformation of the butterfly spring washer assembly 10 can be adjusted by adjusting the number and combination of the butterfly spring washers, for example Figure 8 The three types of combinations of Belleville spring washers are shown:

[0050] (1) The butterfly spring washers are installed in the same direction, and the stiffness coefficient of the combined spring can be increased by increasing the number of the butterfly spring washers 10 while maintaining the maximum deformation;

[0051] (2) Adjacent butterfly spring washers are installed in reverse order, and the stiffness coefficient of the combined spring can be reduced by increasing the number of butterfly spring washers 10, while increasing the maximum deformation;

[0052] (3) Adjacent butterfly spring washers are installed in the same direction or in opposite directions, i.e., a composite combination. By changing the number and combination type of the butterfly spring washers, a specific combined spring stiffness coefficient and maximum deformation can be flexibly designed;

[0053] According to combinatorics theory, the number of different combination configurations increases dramatically with the number of shims, allowing the spring rate and maximum deflection to be fine-tuned according to actual needs.

[0054] Furthermore, the fixture further comprises a pressing plate 1 and a base 6 ; the front anti-buckling plate and the rear anti-buckling plate 2 are located between the pressing plate 1 and the base 6 ; and the rear anti-buckling plate 2 is fixedly mounted on the base 6 .

[0055] Furthermore, the sample 5 and the surface of the fixture are lubricated with polytetrafluoroethylene spray lubricant, which can minimize the friction between the sample 5 and the fixture. After the lubrication treatment, the friction coefficient of the contact interface can be reduced to about 0.05.

[0056] Furthermore, the front anti-buckling plate is provided with a data collection opening for exposing the groove 54, so that the groove 54 can be visible throughout the test process.

[0057] Furthermore, the front upper anti-buckling plate 3 and the front lower anti-buckling plate 4 are respectively provided with the data collection opening.

[0058] Furthermore, if Figure 2-3 As shown, the wide portions at the upper and lower ends of the parallel section 53 of the specimen 5 are divided into support sections 51, and the support section 51 is connected to the parallel section 53 through an arc-shaped transition section. The support section 51 at the lower end of the parallel section 53 is clamped by the front lower anti-buckling plate 4 and the rear anti-buckling plate 2, and the lower portion of the support section 51 at the upper end of the parallel section 53 is clamped by the front upper anti-buckling plate 3 and the rear anti-buckling plate 2, and the upper portion is a free section 52, which is used to contact the pressure plate 1 during the compression test.

[0059] Furthermore, the total length L of the sample 5 is 31 mm; the length Lf of the free section 52 is 5 mm; the length Lp of the parallel section 53 is 12 mm; the width W of the support section 51 is 16 mm; the length Lg of the groove 54 is 6 mm; and the width Wg of the groove 54 is 5 mm.

[0060] When a compression test is performed using the specimen and test device provided by the present invention, the front anti-buckling plate can move along the thickness direction of the specimen 5 as the thickness of the specimen 5 changes after being compressed. The guide pin 7 is installed on the front anti-buckling plate through a high-temperature bushing 8. When the front anti-buckling plate moves along the thickness direction of the specimen 5, the guide pin 7 is used to perform high-precision positioning and guiding of the movement direction of the front anti-buckling plate. At the same time, the spring clamping device is used to control the clamping force between the front anti-buckling plate and the rear anti-buckling plate 2 through the butterfly spring washer assembly 10 to ensure that the clamp can clamp the specimen 5.

[0061] The groove 54 can solve the problem of premature buckling in the thickness direction when the sample 5 is subjected to a compressive load in the longitudinal direction. A transition zone 55 is respectively provided at the upper and lower ends of the groove of the parallel section of the sample 5. On the one hand, it can improve the deformation uniformity of the sample measurement area and suppress the barrel effect in the sample measurement area (this effect is a negative effect that will change the stress state and reduce the test accuracy). On the other hand, it can also delay the buckling failure of the sample, that is, increase the maximum measurable compressive deformation.

[0062] When the specimen undergoes planar compression deformation, it will expand or stretch in the thickness direction. The guide pins and the spring clamping device provided in the test device of the present invention can enable the front upper anti-buckling plate and the front lower anti-buckling plate to have the ability to allow the specimen to freely stretch in the thickness direction, thereby ensuring the accuracy of the test results. At the same time, the front anti-buckling plate is designed to be a split structure including the front upper anti-buckling plate and the front lower anti-buckling plate, and is respectively installed on the rear anti-buckling plate through the guide pins and the spring clamping device, so that it can be adjusted according to the degree of thickness change after the upper and lower ends of the specimen are compressed, thereby further improving the test accuracy. If the fixture prevents the deformation of the specimen in the thickness direction, it will cause very large thickness stress, which will cause the specimen to be in a bidirectional compressive stress state instead of the desired unidirectional compressive stress state. On the other hand, the increase in thickness pressure will inevitably lead to an increase in friction. The load measured by the sensor of the testing machine includes two parts. One is the deformation resistance of the specimen. The first is the force, and the second is the friction between the sample and the fixture. When the friction is very large, it is necessary to deduct the friction from the total load to ensure the accuracy of the measurement of the sample deformation resistance. However, friction is difficult to measure. The traditional unidirectional compression test method has bidirectional stress effect and friction effect, so it is necessary to perform bidirectional stress correction and friction compensation. When the sample and the test device provided by the present invention are used for compression test, when the sample is deformed under pressure, the thickness of the support section of the sample clamped by the fixture increases less, and the thickness of the parallel section increases more. Since the parallel section is not in contact with the front anti-buckling plate, the increase in thickness will not affect the clamping force of the butterfly spring washer assembly. Therefore, the clamping force passively applied by the butterfly spring washer assembly due to the increase in sample thickness is relatively small. In addition, the friction coefficient is also very small, so the friction is very small and can be ignored. Therefore, the test device provided by the present invention can obtain high measurement accuracy without bidirectional stress correction and friction compensation.

[0063] When performing compression tests, you can use a universal materials testing machine MTS with an internal load cell. The maximum measurable load is 100kN. The end loading method is used, that is, the compressive load is applied through the two end faces of the sample. The pressure plate and base of the test device are respectively installed on the upper and lower chucks of the test machine. In order to minimize the load eccentricity, the electronic angle meter can be used to carefully center the test machine before the test. For high temperature environments, the MTS 651 environmental chamber is used to control the ambient temperature of the sample.

[0064] When the experimental device provided by the present invention is used to measure strain, a method based on digital image correlation can be used. The system performs full-field strain distribution measurement on the groove surface area of ​​the specimen using a Point Grey Research GRAS-50S5M-C industrial camera with a TamronAF 180mm f / 3.5 macro lens. The strain analysis parameters for the strain measurement process are: subset size of 31 pixels, step size of 4, and strain filter size of 9 pixels, achieving a consistent resolution of 0.016 mm / pixel. Three longitudinal and three transverse virtual extensometers are set up to measure the average strain in the length and width directions of the specimen.

[0065] In order to evaluate the performance of the test device described in the present invention, the research materials selected are four commercial-grade metal plates, including DP600 steel with a nominal thickness of 1.5 mm, AA5182-O aluminum alloy with a thickness of 1.5 mm, AA7075-T6 aluminum alloy with a nominal thickness of 2.0 mm, and ZEK100-F magnesium alloy with a thickness of 1.6 mm. A large number of studies have shown that the tensile true stress-strain curve and the compressive true stress-strain curve of DP600 steel, AA5182-O and AA7075-T6 aluminum alloy under monotonic loading conditions have good consistency, so they can be used to evaluate the accuracy of compression test results; when using the above four metal plates to evaluate the performance of the test device, all samples were subjected to compression tests at temperatures ranging from 23°C to 200°C along the rolling direction of the plate, and a K-type thermocouple was used to measure the actual sample temperature at the groove position under each temperature condition.

[0066] The results show that the true stress-strain curves of steel and aluminum alloy plates under tension and compression conditions have good consistency, indicating that the test device has high accuracy; in addition, most tests obtained a maximum compressive strain greater than 0.2 before the specimen buckled.

[0067] The ZEK100-F magnesium alloy plate was tested in the temperature range of 23°C to 200°C. When the temperature reached 175°C, the compression true stress-strain curve showed a special S-shape, which indicated the existence of twins. At higher temperatures, dislocation slip dominated the plastic deformation. At 200°C, the compression curve returned to a typical concave shape.

[0068] The above test results verify the effectiveness and feasibility of the test device of the present invention.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A specimen for uniaxial in-plane compression test of thin plate material at high temperature, characterized in that: The sample is a dog-bone-shaped sample, and the parallel section in the middle of the sample includes a groove located on the front side and transition areas located at the upper and lower ends of the groove; The ratio of the groove length to the parallel section length is 1 / 3 to 3 / 4; the ratio of the groove depth to the thickness of the portion of the sample excluding the groove is 0.025 to 0.

1.

2. A uniaxial in-plane compression test device for thin plate materials at high temperature, using the sample as claimed in claim 1, characterized in that: It also includes a clamp; the clamp includes a front anti-buckling plate and a rear anti-buckling plate, and the sample is clamped between the front anti-buckling plate and the rear anti-buckling plate; the front anti-buckling plate is installed on the rear anti-buckling plate through a guide pin and a spring clamping device, and the spring clamping device includes a butterfly spring washer assembly; the front anti-buckling plate is provided with positioning pins for limiting the left and right sides of the sample.

3. The uniaxial in-plane compression test device for thin plate materials at high temperature according to claim 2, characterized in that: The spring clamping device also includes a bolt and a nut, wherein the bolt passes through the front anti-buckling plate and the rear anti-buckling plate and is fixed by the nut, and the butterfly spring washer assembly is sleeved on the bolt and located between the bolt head and the front anti-buckling plate.

4. The uniaxial in-plane compression test device for thin plate materials at high temperature according to claim 2, characterized in that: The front anti-buckling plate comprises an upper front anti-buckling plate and a lower front anti-buckling plate which are arranged at the upper and lower parts; the lower surface of the specimen is flush with the upper surface of the base; the upper front anti-buckling plate and the lower front anti-buckling plate are respectively installed on the rear anti-buckling plate through the guide pins and the spring clamping device.

5. The uniaxial in-plane compression test device for thin plate materials at high temperature according to claim 4, characterized in that: The front upper anti-buckling plate and the front lower anti-buckling plate are respectively provided with two positioning pins.

6. The uniaxial in-plane compression test device for thin plate materials at high temperature according to claim 2, characterized in that: The butterfly spring washer assembly comprises a plurality of butterfly spring washers, and the stiffness coefficient and the maximum deformation of the butterfly spring washer assembly can be adjusted by adjusting the number and combination of the butterfly spring washers.

7. The uniaxial in-plane compression test device for thin plate materials at high temperature according to claim 2, characterized in that: The front anti-buckling plate is provided with a data collection opening for exposing the groove.

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