Tensile test device and test piece

Abstract

To provide a test piece with which multiple rounds of tensile test can be performed with a single test piece, and a tensile test device capable of testing the test piece quickly and repeatedly.SOLUTION: Provided is a tensile test device for performing tensile test of a test piece having a plurality of gripping parts and a tension part. The tensile test device comprises: holding means for fixing one end of the test piece in position; sandwiching means for sandwiching one of the gripping parts of the test piece; tensile force addition means for adding tensile force to the test piece; displacement measurement means for measuring the displacement of the gripping part; load measurement means for measuring the load acting upon the tension part; and strain measurement means for measuring strain of the tension part. At least one of the holding means and the sandwiching means includes means for aligning the positions of the gripping part and the sandwiching means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Tensile testing is a well-known method for measuring the mechanical properties of materials. In order to reduce the influence of measurement errors and obtain highly accurate results, it is common practice to repeat the same test several times on the same sample, not just for tensile testing. [Background technology]

[0002] Patent Document 1 discloses a tensile testing device that automatically performs tensile tests on a large number of test pieces in succession, and that is equipped with a transport device that removes the test pieces from a storage container and transports them to a predetermined position in the tensile testing device body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-117024 Summary of the Invention [Problem to be solved by the invention]

[0004] Because the test specimen is destroyed during the tensile test, repeated testing required preparing multiple test specimens for each test cycle. Furthermore, the test specimen had to be replaced after each measurement, making repeated measurements time-consuming.

[0005] An object of the present invention is to provide a test piece that can be used to perform multiple tensile tests on a single test piece, and a tensile testing device that can quickly perform repeated tests using the test piece. [Means for solving the problem]

[0006] The tensile testing apparatus of the present invention is a tensile testing apparatus for conducting tensile tests on a test piece having a plurality of gripping portions and tensioning portions, and is equipped with a holding means for fixing one end of the test piece, a clamping means for clamping one of the gripping portions of the test piece, a tensile force applying means for applying a tensile force to the test piece, a displacement measuring means for measuring the displacement of the gripping portion, a load measuring means for measuring the load applied to the tensioning portion, and a strain measuring means for measuring the strain of the tensioning portion, and at least one of the holding means and the clamping means is equipped with a means for aligning the gripping portion with the clamping means.

[0007] The tensile testing device may further include a temperature adjusting means for controlling the temperature of the test piece.

[0008] The test piece according to the present invention is a test piece for a tensile test, and has a plurality of tensile portions arranged on one side of the test piece.

[0009] The test specimen may have a hole for fastening to a holding means of a tensile testing device.

[0010] Any of the above test pieces may have a notch in the tensile portion. [Effects of the Invention]

[0011] The present invention provides a test piece that can be used to perform multiple tensile tests on a single test piece, and a tensile testing device that can quickly perform repeated tests using the test piece. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic side view showing an example of a tensile testing device. [Figure 2] FIG. 1 is a schematic top view showing an example of a tensile testing device. [Figure 3] FIG. 1 is a schematic top view showing an example of a tensile testing device. [Figure 4] FIG. 2 is a block diagram showing an example of a control means of a tensile testing device. [Figure 5]FIG. 1 is a schematic diagram illustrating an example of a test piece. [Figure 6] FIG. 6 is an enlarged view of part A in FIG. 5. [Figure 7] FIG. 10 is a schematic diagram showing another example of a test piece. [Figure 8] FIG. 10 is a schematic diagram showing another example of a test piece. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same components in each embodiment are designated by the same reference numerals, and their description will be omitted or simplified. For clarity of explanation, the following description and drawings will be simplified as appropriate, and the scale of each component may differ significantly. Terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "perpendicular," "orthogonal," and "identical," are not to be construed as being limited to their strict meanings, but rather as including the range of degrees to which similar functions can be expected. Unless otherwise specified, "~" indicating a range of values ​​includes the values ​​before and after it as the lower and upper limits.

[0014] (First embodiment) The configuration of a tensile testing device will be described with reference to Figures 1 to 3. Figure 1 is a schematic diagram showing an example of a tensile testing device 100. Figures 2 and 3 are top views of Figure 1. Note that the strain measuring means 60 is omitted in Figures 2 and 3. The tensile testing device 100 shown in the example of FIG. 1 includes a holding means 10, a clamping means 20, a tensile force applying means 30, a displacement measuring means 40, a load measuring means 50, and a strain measuring means 60. The holding means 10 is a means for fixing one end of the test specimen 90, and may have a structure that allows the test specimen 90 to be fixed when a tensile test is performed. For example, the holding means 10 may be configured to clamp the test specimen 90 between a stage 11 on which the test specimen 90 is placed and a clip 12. The stage 11 and clip 12 may be driven to open and close by air pressure. Furthermore, if the test specimen 90 has a hole, as described below, the test specimen 90 may be fixed using a conical pin that can be inserted into the hole, or the test specimen 90 may be clamped between the stage 11 and clip 12 and fastened with a screw or bolt. The clamping means 20 includes a pair of openable and closable clamping plates 21 and 22. As shown in Fig. 3, the clamping means 20 clamps one of a plurality of gripping portions 91 of the test piece 90. The opening and closing driving method may be any method that prevents the gripping portion 91 from coming off during the tensile test, and may be, for example, electrically or pneumatically driven. The tensile force applying means 30 is a means for generating a tensile force 31 in the longitudinal direction of the pulling portion 92 (the X-axis direction in the figure), and an example of such a means is an actuator. In the example of FIG. 1, the tensile force applying means 30 is arranged such that an arm 81 and a clamping means 20 connected to the arm 81 are movable in the X-axis direction. Any known actuator can be used, and examples thereof include an electric stage and a voice coil motor (VCM). The displacement measuring means 40 is a means for measuring the displacement of the gripping portion 91. In the example of Fig. 1, it is sufficient that the means is a means for measuring the displacement of the clamping means 20 in the X-axis direction. Any known means can be used as the displacement measuring means, and one example is a voltage differential transformer (LVDT). The load measuring means 50 measures the load applied to the tensioning portion 92. The load measuring means 50 may be a known means, and one example is a load cell. The strain measuring means 60 measures the strain in the tensile portion 92 during the tensile test. When analyzing the strain using digital image correlation (DIC), the strain measuring means 60 is, for example, a digital camera, and may also be a high-speed camera. When analyzing the strain using DIC, a speckle pattern is formed in advance on at least the tensile portion 92 of the test piece 90.

[0015] In the tensile testing apparatus according to the present invention, at least one of the holding means 10 and the clamping means 20 is provided with a means for aligning the gripping portion 91 with the clamping means 20. When the test piece 90 is substantially rectangular and a plurality of gripping portions 91 (and tensile portions 92) are arranged in parallel on one side of the test piece, as shown in Fig. 2, the alignment means may be any means for driving the holding means 10 or the clamping means 20 in the Y-axis direction 61 (the short-side direction of the tensile portions 92), and may be, for example, an actuator.

[0016] Furthermore, a temperature adjusting means for controlling the temperature of the test piece 90 may be provided. The temperature adjusting means may be any means capable of covering the temperature range to be measured, and may be, for example, a Peltier element. The temperature adjusting means may be provided, for example, within the stage 11 of the holding means 10. The temperature adjusting means may further have a temperature measuring unit for measuring the temperature of the test piece 90 or its vicinity. One example of the temperature measuring unit is a thermocouple.

[0017] Next, the shape of the test piece 90 will be described with reference to Fig. 5 to Fig. 8. Fig. 5 is a schematic diagram showing an example of the test piece, and A1 and A2 in Fig. 6 are each independently an enlarged view of part A in Fig. 5. The test piece 90 shown in Figure 5 has multiple gripping portions 91 and tensioning portions 92 arranged in parallel on one side. The number of tensioning portions 92 in the test piece 90 needs to be two or more, and can be adjusted appropriately depending on the number of repeated measurements required. The shape of the tensioning portion 92 may be approximately rectangular as shown in A1 of Figure 6, or may have a notch 93 as shown in A1 of Figure 6. A tensioning portion 92 having a notch 93 breaks near the notch 93, making it easy to control the position of the break. The side on which the gripping portions 91 are arranged and the opposing side are preferably parallel to each other. Furthermore, the side on which the gripping portions 91 are arranged is preferably perpendicular to the longitudinal direction of the tensioning portion 92. This configuration makes it easy to align the gripping portion with the clamping means, and also ensures a consistent tension direction in the tensile test.

[0018] Fig. 7 is a schematic diagram showing another example of a test specimen. The test specimen 90 shown in Fig. 7 has a gate 94 connecting the gripping portion 91. This reduces the risk of load being applied to the tensile portion 92 during transport or storage of the test specimen. The gate 94 may be cut immediately before the tensile test is performed. 8 is a schematic diagram showing another example of a test piece. The test piece 90 shown in FIG. 8 has holes 95, which allow the test piece to be fixed using screws or bolts. The number and shape of the holes 95 are not particularly limited, and any shape may be used as long as the holes can be fixed to the holding means.

[0019] The dimensions and thickness of the test specimen are not particularly limited and may be adjusted as appropriate depending on the tensile test conditions, etc. The material of the test specimen is not particularly limited and any material, such as a polymer material or metal, can be used. For example, the test specimen can be prepared to any dimensions using a cutting machine such as a CNC router (Computer Numerical Router).

[0020] Next, the control means of the tensile testing apparatus 100 will be described with reference to Fig. 4. Fig. 4 is a block diagram showing an example of the control means of a tensile testing apparatus. The control means 70 shown in the example of Fig. 4 includes an input unit 71, an output unit 72, a calculation unit 73, a control unit 74, and a storage unit 75. The control means 70 may be a dedicated machine, or may be a known personal computer, PDA, tablet terminal, etc.

[0021] The input unit 71 is an input means for accepting input of various information for conducting a tensile test using the tensile test apparatus 100. The input unit 71 has at least a means for inputting displacement information of the test piece, information on the load acting on the test piece, and an image captured by a strain measuring means (for example, terminals connectable to the displacement measuring means 40, the load measuring means 50, and the strain measuring means 60), and may further have a means for inputting temperature information from a temperature measuring unit, and may also be equipped with a keyboard, a touch panel, various switches, and the like, as necessary.

[0022] The output unit 72 is an output means for outputting various information required to carry out an indentation test using the tensile tester 100, and is configured as, for example, a monitor.

[0023] The calculation unit 73 calculates a load-displacement diagram of the test specimen from information on the load applied to the test specimen and information on the displacement of the test specimen. The calculation unit 73 also calculates a stress-strain diagram from image information obtained from the strain measurement means. From these diagrams, it is also possible to calculate Young's modulus, tensile strength, breaking elongation, upper yield point, lower yield point, yield strength, and the like. Specifically, the calculation unit 73 is configured with a CPU, various programs interpreted and executed on the CPU (including basic control programs such as an OS and application programs that are run on the OS and realize specific functions), and internal memory such as RAM for storing programs and various data.

[0024] The storage unit 75 is a storage means for storing various information required for processing by the control means 70, and is configured by, for example, a hard disk or other recording medium. The storage unit 75 may store, for example, displacement information of the test piece, information on the load applied to the test piece, information on images captured by the strain measuring means, temperature information of the test piece 90, and the measurement time, and may also store the results calculated by the calculation unit 73. The storage unit 75 may also store the various programs described above and a program for executing the interfacial failure rate measurement method.

[0025] The control unit 74 controls at least the components constituting the tensile testing apparatus 100 and the control means 70, and may, for example, control the opening and closing of the clamping means 20, control the tensile force applying means 30, control the temperature of the test piece 90, and control the alignment of the gripping part 91 with the clamping means 20. Like the calculation unit 73, the control unit 74 is configured with a CPU, various programs interpreted and executed on the CPU, and an internal memory such as a RAM for storing the programs and various data.

[0026] The tensile testing apparatus 100 of the first embodiment described above uses a test piece 90 having multiple gripping portions and tensioning portions, allowing multiple tensile tests to be performed on a single test piece, enabling rapid repetitive testing. In particular, even when measurements are performed under specific temperature conditions, rapid measurements are possible because only temperature control of a single test piece is required.

[0027] The above-described embodiments and their modifications are described as examples for the purpose of explaining the technical content of the present invention, and are not intended to limit the technical scope of the present invention to the contents of these descriptions. The technical scope of the present invention includes modifications, substitutions, additions, and omissions to the extent that a person skilled in the art can conceive of within the scope of the specification, drawings, and claims or equivalents thereto. [Explanation of symbols]

[0028] 10 Retention means 11 Stages 12 clips 20 Clamping means 21, 22 Holding plate 30 tension applying means 31 Tensile force 40 Displacement measuring means 50 Load measuring means 60 Strain measurement means 70 Control Means 71 Input section 72 Output section 73 Calculation Unit 74 Control Unit 75 Memory section 81 Arm 90 test specimens 91 Grip 92 Tensile section 93 Notch Gate 94 95 holes 100 Tensile testing equipment

Claims

1. A tensile testing device for performing a tensile test on a test piece having a plurality of gripping portions and tensioning portions, a holding means for fixing one end of the test piece; a clamping means for clamping one of the gripping portions of the test piece; a tensile force applying means for applying a tensile force to the test piece; a displacement measuring means for measuring the displacement of the gripping portion; a load measuring means for measuring a load applied to the tension portion; a strain measuring means for measuring the strain of the tension portion, A tensile testing device, wherein at least one of the holding means and the clamping means includes a means for aligning the gripping portion with the clamping means.

2. 10. The tensile testing apparatus of claim 1, further comprising a temperature adjusting means for controlling the temperature of the test specimen.

3. A test piece for a tensile test, A test piece having a plurality of tensile portions arranged on one side of the test piece.

4. 4. The test specimen of claim 3, wherein the test specimen has a hole for being secured to a holding means of a tensile testing apparatus.

5. 4. The test specimen of claim 3, further comprising a notch in the tension section of the test specimen.

Images