Tensile specimen gauge length marking device and tensile method

Abstract

The application discloses a tensile specimen gauge length marking device and a tensile method, which comprises a bearing mechanism, the bearing mechanism comprises two symmetrically arranged driving parts; two symmetrically arranged tensile mechanisms, the tensile mechanism comprises a synchronous assembly fixedly connected with the driving part, a plurality of pushing assemblies and a connecting assembly are arranged in the synchronous assembly, and the synchronous assembly comprises a tensile table; the connecting assembly is provided with a detachable fixing assembly; and the fixing assembly fixedly clamps a specimen. The application can simultaneously perform tensile tests on multiple specimens; when any specimen is broken, the clamping part of the fixed broken specimen can be separated from the tensile table, the remaining specimens can continue to perform tensile tests, the distance moved by the two symmetrically arranged clamping parts is added, the distance at which the tensile specimen is broken is determined, and the distance is recorded. The application not only has simple operation, but also greatly improves the tensile test efficiency of the specimen.

Description

Technical Field

[0001] This invention belongs to the field of mechanical property testing technology, and particularly relates to a gauge length marking device for tensile specimens and a tensile method. Background Technology

[0002] The test that determines a series of properties of a material under tensile load is also known as a tensile test. It is one of the basic methods for testing the mechanical properties of materials. The tensile test refers to the test method for determining the properties of a material under axial tensile load.

[0003] Before and after a tensile test, a measuring device is used to measure the gauge length of the tensile specimen. The data obtained can determine the material's elastic limit, elongation, elastic modulus, proportional limit, reduction of area, tensile strength, yield point, yield strength, and other tensile properties. Therefore, the accuracy and stability of the measuring device are crucial for verifying whether the material meets the specified standards and for studying the material's performance.

[0004] Existing tensile testing equipment can only perform tensile tests on a single material. When multiple materials need to be tested, it requires a lot of time and manpower, which is very inconvenient. Summary of the Invention

[0005] To address the problems in the prior art, the present invention proposes the following technical solution:

[0006] A gauge length marking device for tensile specimens, comprising:

[0007] The support mechanism includes two symmetrically arranged drive units;

[0008] Two symmetrically arranged tensioning mechanisms, each tensioning mechanism including a synchronization component fixedly connected to a drive unit, the synchronization component having multiple pushing components and connecting components installed inside, and the synchronization component including a tensioning table, the connecting component having a detachable fixing component installed, the fixing component fixing and holding the sample;

[0009] The connecting assembly includes a plug-in block, a connecting plate is fixedly connected to the outer wall of the plug-in block, a detachable plug-in rod is installed on the connecting plate and is installed on the inner wall of the stretching table through a sliding part, and one end of the plug-in rod is fixedly connected to a loop frame that cooperates with the trapezoidal block.

[0010] The fixing assembly includes a plug-in plate that plugs into the plug-in block. One side of the plug-in plate extends to the outside of the tensile table and is fixedly connected to a clamping part, in which the sample is fixed.

[0011] The drive unit moves the synchronous component to perform a tensile test on the sample fixed in the clamping part. When the sample breaks, one side of the trapezoidal block and the two-way loop frame moves to control the plug block away from the plug plate, thus keeping the broken sample at the location where the break occurred.

[0012] As a preferred embodiment of the above technical solution, the driving component includes:

[0013] The second pressing rod is movably sleeved in the inner ring of the stretching table. One end of the second pressing rod inside the stretching table is fixedly connected to a trapezoidal block. The inclined part of the trapezoidal block is in contact with the inner wall of the U-shaped frame, and both sides of the trapezoidal block are fixedly connected to sliding sleeves. The inner ring of the sliding sleeve is movably sleeved with a guide rod. The two ends of the guide rod are fixedly connected to the inner walls of both sides of the stretching table, respectively. One side of the sliding sleeve is fixedly connected to an elastic part. The end of the elastic part away from the sliding sleeve is fixedly connected to the inner wall of the stretching table.

[0014] As a preferred embodiment of the above technical solution, the sliding part includes:

[0015] Guide rod three is movably sleeved in the inner ring of the connecting plate, and both ends of guide rod three are fixedly connected to the inner walls of the two sides of the stretching table, respectively. One side of the connecting plate is fixedly connected to elastic part three, and the end of elastic part three away from the connecting plate is fixedly connected to the inner wall of the stretching table. The outer ring of the insertion rod is fixedly sleeved with a baffle. The end of the insertion rod away from the loop frame passes through the connecting plate and is threaded with a threaded sleeve. The connecting plate is located between the baffle and the threaded sleeve.

[0016] As a preferred embodiment of the above technical solution, the synchronization component includes:

[0017] The first pressing rod has one end movably sleeved in the inner ring of the stretching table, and the other end of the first pressing rod has a guide rod movably sleeved in the inner ring. The side of the stretching table away from the clamping part is fixedly connected to the driving part. The end of the guide rod away from the first pressing rod is fixedly connected to the stretching table. The inside of the first pressing rod is provided with an elastic part that is fixedly connected to the guide rod. The outer wall of the first pressing rod is fixedly connected to a trapezoidal block that abuts against the trapezoidal block.

[0018] The tensile method according to the tensile specimen gauge length marking device described in any of the above-mentioned claims includes the following steps:

[0019] S10, Sample Marking

[0020] Multiple samples of the same material are selected and labeled, and two or more labeling methods are used.

[0021] S20, Tensile Test

[0022] Multiple samples are fixed on a tensile testing mechanism for tensile testing;

[0023] S30, Collect Data

[0024] Collect tensile strength data for each specimen and verify whether the data conforms to a normal distribution;

[0025] S40. Establishing a Model

[0026] A normal distribution model was established based on the tensile strength data of multiple specimens, and its function is:

[0027] ƒ

[0028] Where x is a variable, μ is the mean, and σ is the standard deviation;

[0029] S50, Result Output

[0030] The optimal labeling method is determined based on the S40 normal distribution model.

[0031] As a preferred embodiment of the above technical solution, in S10, the marking method for the sample is laser method, punching method, or other similar methods.

[0032] As a preferred embodiment of the above technical solution, in S10, the gauge length marking in the specimen marking is used to calculate the elongation after fracture. The formula for calculating the elongation after fracture is A% = / L0 × 100%, where L U L0 is the gauge length after fracture, and L0 is the original gauge length. The original gauge length L0 = 25 mm, and the sample marking deviation L0 = 25 mm ± 0.25 mm.

[0033] As a preferred embodiment of the above technical solution, in the tensile test, S20: S21: the specimen is fixed by fixing multiple specimens between two tensile tables using multiple symmetrically arranged clamping parts.

[0034] S22. Specimen tensioning: Simultaneously activate two drive units to move two tensioning tables to a side that is far apart from each other, and perform tensile tests on multiple specimens located in the middle at the same time.

[0035] S23. Specimen breakage: When any specimen breaks, the drive unit is shut down, and the corresponding pressing rod two is pushed to move trapezoidal block two closer to the loop frame. Through the friction between the inclined side of trapezoidal block two and the loop frame, the insertion block can be moved away from the insertion plate. When the insertion block is completely separated from the insertion plate, the clamping part that fixes the broken specimen will separate from the tensile table. The drive unit is restarted to continue the tensile test on the remaining specimens. The distances moved by the two symmetrically set clamping parts are added together to determine the distance at which the tensile specimen breaks and are recorded.

[0036] As a preferred embodiment of the above technical solution, in S30, during data collection, multiple comparisons are used to further determine whether there is a difference between the means of the two groups. The Levene test is used to compare the normal distribution of the two samples with different labeling methods to test whether the variances are the same.

[0037] As a preferred embodiment of the above technical solution, in S30, during data collection, the deviation of the data under two different methods is compared by an F-test to determine whether there is a significant difference in precision.

[0038] The beneficial effects of this invention are as follows:

[0039] 1. This invention can perform tensile tests on multiple specimens simultaneously. When any specimen breaks, the clamping part that fixes the broken specimen can be separated from the tensile table, and the remaining specimens can continue to be tensile tested. Finally, the distances moved by the two symmetrically set clamping parts are added together to determine the distance at which the tensile specimen breaks and the data is recorded. This not only makes the operation simple but also greatly improves the efficiency of tensile testing of specimens.

[0040] 2. This invention compares different marking methods to determine the influence of different markings on the tensile test of the specimen, and selects the optimal marking method. Attached Figure Description

[0041] Figure 1 The diagram shown is a schematic representation of the gauge length marking device for the tensile specimen in the embodiment.

[0042] Figure 2 The diagram shown is a structural schematic of the tensioning mechanism in the embodiment;

[0043] Figure 3 The diagram shown is a structural schematic of the synchronization component in the embodiment;

[0044] Figure 4 The diagram shown is a structural schematic of the pushing component and the fixing component in the embodiment;

[0045] Figure 5 The diagram shown is a structural schematic of the connecting component and the fixing component in the embodiment;

[0046] Figure 6 The diagram shown is a structural schematic of the pushing component and the connecting component in the embodiment;

[0047] Figure 7 The diagram shown is a structural schematic of the connecting component in the embodiment;

[0048] Figure 8 The diagram shown is a structural schematic of the fixing component in the embodiment;

[0049] Figure 9 The diagram shown is a schematic diagram of the equal variance test in the embodiment.

[0050] Explanation of reference numerals in the attached figures:

[0051] 100. Bearing mechanism; 101. Bearing platform; 102. Drive unit; 200. Tensioning mechanism; 210. Synchronization assembly; 211. Tensioning table; 212. Pressing rod one; 213. Guide rod one; 214. Elastic part one; 215. Trapezoidal block one; 220. Pushing assembly; 221. Pressing rod two; 222. Trapezoidal block two; 223. Sliding sleeve; 224. Guide rod two; 225. Elastic part two; 230. Connecting components; 231, plug-in block; 232, connecting plate; 233, plug-in rod; 234, loop frame; 235, baffle; 236, threaded sleeve; 237, guide rod three; 238, elastic part three; 240, fixing components; 241, plug-in plate; 242, moving block; 244, clamping seat; 245, fixing frame; 246, threaded rod; 247, upper clamping plate; 248, guide rod four; 249, rubber protrusion. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0053] GB / T 228.1 and GB / T 228.2 specify the method for marking the gauge length of tensile specimens. Small marks, fine lines, or fine ink lines may be used to mark the original gauge length, but notches that cause premature fracture must not be used as markers. The marking of the original gauge length should be accurate to ±1%.

[0054] ASTM E8 specifies that markings can be made lightly using a dotting machine, compass, or recommended ink. Methods for marking elongation at break include the scribing method and the dotting method.

[0055] Example 1

[0056] like Figure 1 , Figure 2 , Figure 5 , Figure 7 and Figure 8As shown, the tensile specimen gauge length marking device includes a bearing mechanism 100 and two symmetrically arranged tensile mechanisms 200. The bearing mechanism 100 includes two symmetrically arranged drive units 102 and a support platform 101. The drive units 102 are hydraulic cylinders. The outer surface of the support platform 101 is provided with scale lines. The drive units 102 are fixed to the top of the support platform 101. The tensile mechanism 200 includes a synchronization component 210 fixedly connected to the drive units 102. Multiple push components 220 and connecting components 230 are installed inside the synchronization component 210. The synchronization component 210 includes a tensile platform 211, and the connecting components 230 are installed... The device includes a detachable fixing component 240 that holds the sample in a fixed clamp. The connecting component 230 includes a plug-in block 231. A connecting plate 232 is fixedly connected to the outer wall of the plug-in block 231. A detachable plug-in rod 233 is installed on the connecting plate 232 and is mounted on the inner wall of the tensile table 211 via a sliding part. One end of the plug-in rod 233 is fixedly connected to a U-shaped frame 234 that cooperates with the trapezoidal block 222. The fixing component 240 includes a plug-in plate 241 that plugs into the plug-in block 231. One side of the plug-in plate 241 extends to the outside of the tensile table 211 and is fixedly connected to a clamping part, in which the sample is fixed.

[0057] Specifically, the drive unit 102 drives the synchronous component 210 to move and perform tensile testing on the specimen fixed in the clamping part. Multiple specimens can be tensile tested simultaneously. When any specimen breaks, the trapezoidal block 222 moves to one side of the loop frame 234 to control the plug block 231 to move away from the plug plate 241. This separates the clamping part that fixes the broken specimen from the tensile table 211, allowing the remaining specimens to continue to be tensile tested. Finally, the distances moved by the two symmetrically set clamping parts are added together to determine the distance at which the tensile specimen breaks and record the result. This not only simplifies the operation but also greatly improves the efficiency of tensile testing of specimens.

[0058] Figure 5 and Figure 6As shown, the pushing component 220 includes a second pressing rod 221, which is movably sleeved in the inner ring of the stretching table 211, allowing it to be pushed and pulled. A trapezoidal block 222 is fixedly connected to one end of the pressing rod 221 inside the stretching table 211. The inclined portion of the trapezoidal block 222 is in contact with the inner wall of the loop frame 234. When the trapezoidal block 222 moves towards the loop frame 234, the loop frame 234 moves upward along the axial direction of the sliding portion due to friction with the inclined portion. Both sides of the second 222 are fixedly connected to the sliding sleeve 223. The inner ring of the sliding sleeve 223 is movably fitted with the second guide rod 224. The two ends of the second guide rod 224 are fixedly connected to the inner walls of the two sides of the stretching table 211 respectively. One side of the sliding sleeve 223 is fixedly connected to the second elastic part 225. The second elastic part 225 is a spring. The spring is sleeved on the outer ring of the second guide rod 224 to prevent the spring from bending under force. The end of the second elastic part 225 away from the sliding sleeve 223 is fixedly connected to the inner wall of the stretching table 211.

[0059] Specifically, by pushing the pressing rod 221 into the interior of the stretching table 211, the trapezoidal block 222 moves towards one side of the loop frame 234. Since the inclined part of the trapezoidal block 222 is in contact with the inner wall of the loop frame 234, the loop frame 234 moves upward along the axis of the sliding part through friction with the inclined part, thereby driving the plug block 231 to separate from the plug plate 241. After releasing the pressing rod 221, the elastic part 225 will push the trapezoidal block 222 and the pressing rod 221 back to their original positions.

[0060] like Figure 5 , Figure 6 and Figure 7 As shown, the sliding part includes a guide rod 237, which is movably sleeved in the inner ring of the connecting plate 232. Both ends of the guide rod 237 are fixedly connected to the inner walls of both sides of the stretching table 211, so that the connecting plate 232 can only move along the axial direction of the guide rod 237. An elastic part 238 is fixedly connected to one side of the connecting plate 232. The elastic part 238 is a spring, which is sleeved on the outer ring of the guide rod 237 to prevent the spring from bending under force. The end of the elastic part 238 away from the connecting plate 232 is fixedly connected to the inner wall of the stretching table 211. The initial position of the insertion block 231 is above the insertion plate 241 and is inserted into it.

[0061] like Figure 5 , Figure 6 and Figure 7 As shown, the outer ring of the insertion rod 233 is fixedly fitted with a baffle 235. The end of the insertion rod 233 away from the loop frame 234 passes through the connecting plate 232 and is threadedly connected with a threaded sleeve 236. The connecting plate 232 is located between the baffle 235 and the threaded sleeve 236.

[0062] The threaded sleeve 236 is connected to the insertion rod 233 by a thread, which makes it easy to separate from the insertion rod 233. After the threaded sleeve 236 is separated from the insertion rod 233, the insertion rod 233 can be pulled out from the inner ring of the connecting plate 232.

[0063] like Figure 2 , Figure 3 and Figure 4 As shown, the synchronization component 210 includes a pressing rod 212. One end of the pressing rod 212 is movably sleeved in the inner ring of the stretching table 211, and the other end of the pressing rod 212 is movably sleeved in the inner ring of the guide rod 213. The side of the stretching table 211 away from the clamping part is fixedly connected to the driving part 102. The pressing rod 212 can move in the outer ring of the guide rod 213 and the inner ring of the stretching table 211. The end of the guide rod 213 away from the pressing rod 212 is fixedly connected to the stretching table 211. The pressing rod 212 is provided with an elastic part 214 fixedly connected to the guide rod 213. The elastic part 214 is a spring. The outer wall of the pressing rod 212 is fixedly connected with a trapezoidal block 215 that abuts against the trapezoidal block 222. The number of trapezoidal blocks 215 is the same as the number of trapezoidal blocks 222.

[0064] Specifically, when the pressing rod 212 is pushed to move into the stretching table 211, since the inclined part of the trapezoidal block 215 abuts against the side wall of the trapezoidal block 222, the pressing rod 212, while moving the trapezoidal block 215 towards one side of the trapezoidal block 222, will push the trapezoidal block 222 towards the side closer to the U-shaped frame 234, causing multiple insertion blocks 231 to move upwards simultaneously, thus allowing multiple insertion plates 241 to be inserted into the stretching table 211 at the same time. Inside, after releasing the pressing rod 212, the pressing rod 212 will drive the trapezoidal block 215 away from the trapezoidal block 222 through the force of the elastic part 214. The trapezoidal block 222 will move away from the U-shaped frame 234 through the force of the elastic part 225. The plug-in block 231 will be plugged into the plug-in plate 241 through the force of the elastic part 338, so that multiple clamping parts can be connected to the tensile table 211 at the same time. This not only makes the operation simple, but also makes it convenient to fix and stretch multiple samples.

[0065] Example 2

[0066] like Figure 2 , Figure 4 and Figure 5As shown, the tensile specimen gauge length marking device, compared to Embodiment 1, in this embodiment, the clamping part includes a clamping seat 244 fixedly connected to the plug plate 241. A fixing frame 245 is fixedly connected to the top of the clamping seat 244. A lead screw 246 is threadedly connected to the side of the fixing frame 245 away from the clamping seat 244. An upper clamping plate 247 is rotatably connected to the end of the lead screw 246 near the clamping seat 244. A guide rod 248 is fixedly connected to the outer wall of the upper clamping plate 247. The guide rod 248 is located away from the upper clamping plate 247. The end-through fixing frame 245 has a guide rod 248 and a lead screw 246 located on the same side. The guide rod 248 prevents the upper clamping plate 247 from rotating with the lead screw 246. The inner walls of the clamping seat 244 and the upper clamping plate 247 are provided with multiple rubber protrusions 249. The sample is placed between the clamping seat 244 and the upper clamping plate 247. The rubber protrusions 249 increase the friction with the sample. The bottom of the plug plate 241 is fixedly connected to a moving block 242, which is slidably connected to the support platform 101.

[0067] Specifically, rotating the lead screw 246 causes the upper clamping plate 247 to move away from the clamping seat 244. Through the cooperation of the guide rod 248 and the fixing frame 245, the upper clamping plate 247 cannot rotate with the lead screw 246. After the upper clamping plate 247 moves to the farthest distance, it places the sample on the clamping seat 244. Then, the lead screw 246 is rotated in the opposite direction to drive the upper clamping plate 247 closer to the clamping seat 244 until the sample is firmly fixed.

[0068] A tensile test specimen gauge length marking device tensile method, comprising the following steps:

[0069] S10, Sample Marking

[0070] Multiple samples of the same material are selected and labeled, and two or more labeling methods are used.

[0071] S20, Tensile Test

[0072] Multiple samples are fixed on the tensile mechanism 200 for tensile testing;

[0073] S30, Collect Data

[0074] Collect the tensile strength data for each specimen, as shown in the table below, and verify whether the data conforms to a normal distribution.

[0075] Statistical analysis of gauge length measurements using different marking methods

[0076]

[0077] S40. Establishing a Model

[0078] A normal distribution model was established based on the tensile strength data of multiple specimens, and its function is:

[0079] ƒ

[0080] Where x is a variable, μ is the mean, and σ is the standard deviation;

[0081] S50, Result Output

[0082] The optimal labeling method is determined based on the S40 normal distribution model.

[0083] S10. In the marking of the sample, the marking methods include laser method, punching method, etc.

[0084] S10. In the specimen markings, the gauge length markings are used to calculate the elongation at break. The formula for calculating the elongation at break is A% = (L... U -L0) / L0×100%, L U L1 represents the gauge length after the break, and L2 represents the original gauge length.

[0085] The original gauge length L0 = 25 mm, and the sample marking deviation L0 = 25 mm ± 0.25 mm.

[0086] S20. In the tensile test: S21. Specimen fixation: Multiple specimens are fixed between two tensile tables 211 by multiple symmetrically arranged clamping parts.

[0087] S22, Specimen stretching: Simultaneously, the two drive units 102 are activated to move the two stretching tables 211 to a side that is far apart from each other, and the multiple specimens located in the middle are subjected to tensile tests at the same time.

[0088] S23. Specimen breakage: When any specimen breaks, the drive unit 102 is shut down, and the corresponding pressing rod 221 is pushed to move the trapezoidal block 222 closer to the loop frame 234. Through the friction between the inclined side of the trapezoidal block 222 and the loop frame 234, the insertion block 231 can be moved away from the insertion plate 241. When the insertion block 231 is completely separated from the insertion plate 241, the clamping part that fixes the broken specimen will separate from the tensile table 211. The drive unit 102 is restarted to continue the tensile test on the remaining specimens. The distances moved by the two symmetrically set clamping parts are added together to determine the distance at which the tensile specimen breaks and the result is recorded.

[0089] S30. During data collection, multiple comparisons are used to further determine whether there is a difference between the means of the two groups.

[0090] S30. During data collection, the Levene test is used to compare the normal distributions of two samples with different labeling methods to test whether their variances are the same.

[0091] S30. During data collection, the F-test is used to compare the deviations of the data from the two groups using different methods to determine whether there is a significant difference in precision.

[0092]

[0093] like Figure 9 As shown in the table above, from a statistical analysis perspective: ① The test of equal variance P=0.145>0.05 indicates that the variance of the test results of the two marking methods is not statistically significantly different, that is, both methods can be used. However, the data from the punching method is more dispersed than the data from the laser method.

[0094] The gauge length marking is used to calculate the elongation at break. The formula for calculating the elongation at break is A% = (LU - L0) / L0 × 100%, where LU is the gauge length after break and L0 is the original gauge length. For the original gauge length L0 = 25mm, when marking the original gauge length, a punch is used to mark the dots and the calculation is based on the nominal size. However, human factors have a significant impact, and the data will appear scattered, resulting in poor consistency of test results. If laser marking is used, the test results are concentrated and stable, with small error and good consistency.

[0095] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. A tensile specimen gauge length marking device, characterized by, The utility model relates to a tensile testing device for testing the tensile strength of sample, comprising: a bearing mechanism (100) comprising two symmetrically arranged driving parts (102); two symmetrically arranged stretching mechanisms (200) comprising a synchronization assembly (210) fixedly connected with the driving part (102), a plurality of pushing assemblies (220) and a connecting assembly (230) installed inside the synchronization assembly (210), and the synchronization assembly (210) comprising a stretching platform (211), the connecting assembly (230) being provided with a detachable fixing assembly (240), and the fixing assembly (240) fixedly clamping a sample; the connecting assembly (230) comprising a plug-in block (231), the outer wall of the plug-in block (231) being fixedly connected with a connecting plate (232), the connecting plate (232) being provided with a detachable plug-in rod (233) and being installed on the inner wall of the stretching platform (211) through a sliding part, one end of the plug-in rod (233) being fixedly connected with a back-shaped frame (234) matched with the trapezoidal block two (222); the fixing assembly (240) comprising a plug-in plate (241) plugged with the plug-in block (231), one side of the plug-in plate (241) extending to the outside of the stretching platform (211) and being fixedly connected with a clamping part, and the sample being fixed in the clamping part; the driving part (102) driving the synchronization assembly (210) to move to stretch and test the sample fixed in the clamping part, when the sample is broken, the trapezoidal block two (222) moving to one side of the back-shaped frame (234) controls the plug-in block (231) to move away from the plug-in plate (241), and the broken sample is stranded at the position where the breaking occurs; the pushing assembly (220) comprising: a second pressing rod (221) movably sleeved in the inner ring of the stretching platform (211), one end of the second pressing rod (221) inside the stretching platform (211) being fixedly connected with the trapezoidal block two (222), the inclined part of the trapezoidal block two (222) being matched with the inner wall of the back-shaped frame (234), both sides of the trapezoidal block two (222) being fixedly connected with a sliding sleeve (223), the inner ring of the sliding sleeve (223) being movably sleeved with a second guide rod (224), both ends of the second guide rod (224) being fixedly connected with the inner walls of both sides of the stretching platform (211), one side of the sliding sleeve (223) being fixedly connected with a second elastic part (225), and one end of the second elastic part (225) away from the sliding sleeve (223) being fixedly connected with the inner wall of the stretching platform (211); the synchronization assembly (210) further comprising: One end of a first pressing rod (212) is movably sleeved in an inner ring of a stretching table (211), and the other end of the first pressing rod (212) is movably sleeved with a first guide rod (213), one side of the stretching table (211) away from the clamping part is fixedly connected with the driving part (102), one end of the first guide rod (213) away from the first pressing rod (212) is fixedly connected with the stretching table (211), the inside of the first pressing rod (212) is provided with a first elastic part (214) fixedly connected with the first guide rod (213), and the outer wall of the first pressing rod (212) is fixedly connected with a first trapezoidal block (215) abutting against a second trapezoidal block (222).

2. The tensile specimen gauge length marking device of claim 1, wherein the slide Comprise: A third guide rod (237) is movably sleeved in an inner ring of a connecting plate (232), and both ends of the third guide rod (237) are fixedly connected with the inner walls of both sides of the stretching table (211), one side of the connecting plate (232) is fixedly connected with a third elastic part (238), one end of the third elastic part (238) away from the connecting plate (232) is fixedly connected with the inner wall of the stretching table (211), the outer ring of the plug rod (233) is fixedly sleeved with a baffle (235), one end of the plug rod (233) away from the meander frame (234) penetrates through the connecting plate (232) and is threadedly connected with a silk sleeve (236), and the connecting plate (232) is located between the baffle (235) and the silk sleeve (236).

3. The tensile specimen gauge length marking method of a tensile specimen gauge length marking apparatus according to claim 1 or 2, characterized by, Comprise the following steps, S10, sample marking Select multiple samples of the same material for marking, and the marking method adopts a laser method or a punch point method; S20, tensile test Fix multiple samples on the stretching mechanism (200) for tensile test; S30, data collection Collect the tensile strength data of each sample and test whether the data conforms to the normal distribution; S40, model establishment A normal distribution model is established according to the tensile strength data of multiple samples, and the function is Wherein, x is a variable, μ is a mean value, and σ is a standard deviation; S50, result output Determine the optimal marking method according to the normal distribution model of S40; In S20, tensile test: S21, sample fixing, fix multiple samples between two stretching tables (211) through multiple symmetrically arranged clamping parts; S22, sample stretching, simultaneously start two driving parts (102) to drive two stretching tables (211) to move away from each other, and simultaneously perform tensile test on multiple samples located in the middle; S23, when any one sample is broken, the driving part (102) is turned off, the second pressing rod (221) corresponding to the broken sample is pushed, the trapezoidal block two (222) moves to the side close to the back-shaped frame (234), the friction between the inclined edge of the trapezoidal block two (222) and the back-shaped frame (234) can drive the plug-in block (231) to move away from the plug-in plate (241), when the plug-in block (231) is completely separated from the plug-in plate (241), the clamping part for fixing the broken sample is separated from the stretching table (211), the driving part (102) is started again to continue to test the remaining samples, the distance moved by the two symmetrically arranged clamping parts is added, the distance at which the sample is broken is determined, and the distance is recorded.

4. The method of gage length marking of a tensile specimen according to claim 3, wherein S10, in the sample marking, the marking of the gauge length is used to calculate the elongation after breaking, the calculation formula of the elongation after breaking A%= (L U -L0) / L0x100%, L U is the length of the gauge length after breaking, L0 is the original gauge length, the original gauge length L0=25mm, and the sample marking deviation is ±0.25mm.

5. The method of gage length marking of a tensile specimen according to claim 3, wherein S30, in the data collection, whether there is a difference between the two groups of average numbers is further determined by multiple comparisons, Levene test is used to compare the normal distribution of two different marking methods, and whether the variances are the same is tested.

6. The method of gage length marking of a tensile specimen according to claim 3, wherein S30, in the data collection, the deviation of the data under two different methods is compared by F test, and whether there is a significant difference in precision is determined.

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