A limiting device and limiting method for composite material compression performance test

Abstract

The application provides a limiting device and a limiting method for composite material compression performance test, the limiting device is used for centering and limiting a test piece, and at least comprises a base, four limiting blocks arranged on the base, and a connecting rod assembly connected to the limiting blocks; X-axis sliding rails and Y-axis sliding rails intersected are arranged on the base; two limiting blocks are used for limiting the test piece on the X-axis sliding rails, and the other two limiting blocks are used for limiting the test piece on the Y-axis sliding rails; the connecting rod assembly controls the movement of the limiting blocks, so that the test piece is accurately centered and limited. The limiting device is arranged, the complexity that the line marking needs to be performed again during the composite material compression switching test is avoided, the consistency of the positions of the same batch of test samples during the test can be ensured by using the limiting device, and the accuracy of the experimental test is improved.

Description

Technical Field

[0001] This invention relates to the field of polymer-based composite material testing technology, and more specifically, to a limiting device and method for limiting the compressive properties of composite materials. Background Technology

[0002] Compression performance testing of polymer-based composites typically involves mounting two parallel platforms on a testing machine, with the relevant performance tests performed between the two platforms. The fixtures or specimens are generally required to be placed in the center of the platform; however, due to inconsistencies in the dimensions of compression fixtures or specimens, uniform positioning is not always possible. Currently, commonly used compression specimen or fixture forms and testing standards are as follows: Figure 1 Use ASTM D3410 / D3410M, "Test Method for Measuring the Compressive Properties of Composite Materials by Shear Loading"; Figure 2 The standard adopted is ASTM D6641 / D6641M, "Test Method for Compression Properties of Polymer-Based Composite Laminates". Figure 3 The standard adopted in this paper is GB-T30968.4 "Test methods for the performance of open-hole load-bearing polymer-based composite laminates - Part 4: Test method for open-hole compressive strength". Figure 4 The standard adopted is ASTM D7137 / D7137M "Standard Test Method for Residual Compressive Strength of Damaged Polymer-Based Composite Boards"; in addition to the above-mentioned compression fixtures needing to be placed between platforms, the compression performance of rigid foams also requires that the specimen be placed in the center of the platform.

[0003] In addition, ASTM D6264, "Standard Test Method for Measuring Damage Resistance of Fiber-Reinforced Polymer Composites to Concentrated Quasi-Static Indentation Forces," is currently widely used to study the damage resistance-related properties of multidirectional polymer matrix composite laminates. This method sometimes requires the use of a perforated fixture to place the specimen for testing. During specimen installation, it is crucial to ensure that the center of the specimen, the center of the fixture perforation, and the center of the indenter are aligned, especially when individual specimens are subjected to intermittent loading; each loading must be performed at the same center position, which is currently often achieved by marking the specimen.

[0004] In summary, while all the above tests require placing the fixture or sample at the center of the platform, there is no specific limiting method. Currently, marking with lines is often used, but this method is inconvenient in practice due to factors such as the observation angle and the size of the marks. Furthermore, the compression fixtures for different testing standards vary in size, requiring re-marking each time a test is switched, which is cumbersome. During testing of the same batch of samples, consistency in position must be ensured, and marking is clearly inefficient and inaccurate. Therefore, it is necessary to redesign a limiting device that ensures both fixture centering and consistent position of samples within the same batch. Summary of the Invention

[0005] In view of this, the present invention aims to propose a limiting device and method for the compressive properties of composite materials, in order to solve the problem that the existing technology does not have a specific limiting method, and currently most of them use the method of marking by scribing. However, this method is affected by factors such as the observation angle and the size of the mark, which is not convenient to operate in practice. At the same time, the compression clamps of different test standards are of different sizes, and the scribing needs to be re-marked every time the test is switched, which is complicated. During the testing of the same batch of samples, it is necessary to ensure the consistency of position, and the scribing method is obviously inefficient and has low accuracy.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] A limiting device for testing the compressive properties of composite materials, wherein the limiting device centers and limits the test specimen, characterized in that the limiting device includes at least a base, four limiting blocks disposed on the base, and a linkage assembly connected to the limiting blocks. The base has intersecting X-axis slide rails and Y-axis slide rails, wherein two limiting blocks limit the test specimen on the X-axis slide rails and two limiting blocks limit the test specimen on the Y-axis slide rails, and the linkage assembly controls the movement of the limiting blocks to ensure accurate centering and limiting of the test specimen.

[0008] The limiting device in this setup ensures that the composite material compression fixture or specimen is located in the center of the testing machine, ensuring the consistency of the position of specimens in the same batch during the testing process and improving the accuracy of the experimental test.

[0009] Furthermore, the base includes at least a chassis, and both the X-axis slide rail and the Y-axis slide rail are configured as groove structures of the chassis.

[0010] In this setup, the groove structure is used to limit the movement of the limiting block.

[0011] Furthermore, the limiting device also includes a fixed slider, and a track block is provided at the lower end of the limiting block, the track block being connected to the fixed slider.

[0012] In this setup, the fixed slider can fix the limit block to limit the test piece, ensuring the accuracy of the experiment.

[0013] Furthermore, the limiting block is provided with a third threaded hole, which extends from the upper end of the limiting block to the track block. The fixed slider is provided with a fifth threaded hole, and the track block is connected to the fixed slider by bolts screwed into the third threaded hole and the fifth threaded hole.

[0014] This setting is used to fix the limit block. By tightening the bolts, the fixed slider can be kept in close contact with the convex track wall, increasing the friction and thus limiting the movement of the limit block.

[0015] Furthermore, a support column is provided on the limiting block, the support column is located at the upper end of the limiting block, and the support column is used to connect the connecting rod assembly.

[0016] Furthermore, the limiting device also includes a limiting rod that passes through the limiting block and is parallel to the fixed slider.

[0017] The limiting rod in this setup can achieve secondary limiting of contact between the fixture or the sample.

[0018] Furthermore, the limiting block is provided with a first through hole and a fourth threaded hole. The limiting rod is inserted into the first through hole, and the limiting block is fixed to the limiting rod by screwing a bolt into the fourth threaded hole.

[0019] Furthermore, the linkage assembly includes a first connecting rod, a second connecting rod, and a washer. The first connecting rod and the second connecting rod have the same length. The first connecting rod and the second connecting rod are detachably connected to the support column. The first connecting rod is located on the second connecting rod. When one end of the first connecting rod and the second connecting rod are simultaneously connected to the support column on the limiting block, the other end of the first connecting rod is fixed to the support column of the adjacent limiting block. A washer is also provided. The other end of the second connecting rod is connected to the support column of the limiting block that is coaxial with the first connecting rod.

[0020] In this setup, the linkage assembly enables precise alignment of the limit block.

[0021] Furthermore, the base also includes a flange connecting plate and a clamping column, the base plate is connected to the flange connecting plate, and the flange connecting plate is connected to the clamping column.

[0022] A limiting method for testing the compressibility of composite materials, using the limiting device described above, includes three limiting modes: mode one involves four limiting blocks moving to limit the movement while the limiting rods on the limiting blocks remain stationary; mode two involves two coaxial limiting blocks moving to limit the movement first, followed by the limiting rods on the other two limiting blocks moving to limit the movement; and mode three involves four limiting blocks moving to limit the movement first, followed by the limiting rods on the limiting blocks moving to limit the movement.

[0023] Compared to existing technologies, the limiting device and method for improving the compressibility of composite materials described in this invention have the following advantages:

[0024] 1) The present invention can position the test fixtures or test specimens for different types of non-metallic materials compression tests, ensuring that the test positions of the same batch of test specimens remain unchanged, and reducing the impact of uncertain factors on the test results;

[0025] 2) The present invention adopts a double sliding rail form to ensure the smooth movement of the four limiting blocks, and a fixed slider is provided in the rail. The bolts are connected to the fixed sliding rail through the threaded holes to fix the limiting blocks.

[0026] 3) The limiting block in this invention has a square hole in the middle, and a movable limiting rod can be installed in the square hole. The limiting rod can complete the secondary limiting task. The limiting rod can be fastened through the threaded hole on the limiting block.

[0027] 4) The upper part of the limiting block in this invention is provided with a support column, which connects the first connecting rod and the second connecting rod to realize the centering function of the test piece;

[0028] 5) The limiting device in this invention can perform dual positioning of the static indentation test fixture and the sample, ensuring that the indentation position is in the same position each time, thus increasing the accuracy of the results. Attached Figure Description

[0029] Figure 1 This is the test apparatus used in the existing ASTM D3410 standard;

[0030] Figure 2 This is the test apparatus used in the existing technology of ASTM D6641;

[0031] Figure 3 The test apparatus used in the prior art as per GB-T30968.4;

[0032] Figure 4 The test apparatus used in the existing technology according to ASTM D7137;

[0033] Figure 5 This is a schematic diagram of the overall structure of the limiting device of the present invention from a first perspective;

[0034] Figure 6 This is a schematic diagram of the overall structure of the limiting device of the present invention from a second perspective;

[0035] Figure 7 for Figure 5 Top view;

[0036] Figure 8 This is an exploded view of the base of the present invention;

[0037] Figure 9 This is an exploded view of the limiting block, the fixing slider, and the limiting rod of the present invention;

[0038] Figure 10 This is a schematic diagram of the overall structure of the linkage assembly of the present invention;

[0039] Figure 11 This is a first-view structural schematic diagram of the chassis of the present invention;

[0040] Figure 12 This is a structural schematic diagram of the chassis of the present invention from a second perspective;

[0041] Figure 13 This is a schematic diagram of the flange connection disc of the present invention;

[0042] Figure 14 This is a schematic diagram of the clamping column of the present invention;

[0043] Figure 15 This is a first-view structural schematic diagram of the limiting block of the present invention;

[0044] Figure 16 This is a schematic diagram of the limiting block of the present invention from a second perspective;

[0045] Figure 17 This is a schematic diagram of the limiting rod of the present invention;

[0046] Figure 18 This is a schematic diagram of the fixed slider of the present invention;

[0047] Figure 19 This is an exploded structural diagram of the linkage assembly of the present invention;

[0048] Figure 20 A schematic diagram of the ASTM D6641 tooling in the prior art;

[0049] Figure 21 A schematic diagram of the ASTM D6641 tooling in the limiting device of the present invention;

[0050] Figure 22 This is a schematic diagram of the static indentation fixture and the sample within the limiting device of the present invention.

[0051] Figure 23These are the right view and front view of the chassis in Embodiment 3 of the present invention;

[0052] Figure 24 These are the right view and front view of the flange connecting plate according to Embodiment 3 of the present invention;

[0053] Figure 25 This is a front view of the clamping column of Embodiment 3 of the present invention;

[0054] Figure 26 This is a front view of the limiting block according to Embodiment 3 of the present invention;

[0055] Figure 27 These are the front view and top view of the limiting rod in Embodiment 3 of the present invention;

[0056] Figure 28 These are the front view and top view of the fixed slider in Embodiment 3 of the present invention.

[0057] Explanation of reference numerals in the attached figures:

[0058] 1-Base, 11-Chassis, 111-Groove Structure, 1111-First X-axis Groove, 1112-Second X-axis Groove, 1113-First Y-axis Groove, 1114-Second Y-axis Groove, 1115-Notch, 1116-U-groove, 1117-Limiting Plate, 112-Circular Beam, 113-First Threaded Hole, 12-Flange Connecting Plate, 121-Settling Hole, 122-Second Threaded Hole, 13-Clamping Column, 131-First Cylinder, 132-Second Cylinder, 2-Limiting Block, 21-Rail Block, 22-First... 23-First through hole, 24-Support column, 25-Fourth threaded hole, 26-A limit block, 27-B limit block, 28-C limit block, 29-D limit block, 3-Connecting rod assembly, 31-First connecting rod, 311-Second through hole, 312-Third through hole, 32-Second connecting rod, 321-Fourth through hole, 322-Fifth through hole, 33-Gasket, 331-Sixth through hole, 4-Fixed slider, 41-Fifth threaded hole, 5-Limiting rod, 51-Top plate, 52-Sliding arm, 6-ASTM D6641 standard fixture, 7-Static indentation fixture, 8-Sample, a-Right view of chassis, b-Front view of chassis, c-Right view of flange connection plate, d-Front view of flange connection plate, e-Front view of limiting rod, f-Top view of limiting rod, g-Front view of fixed slider, h-Top view of fixed slider. Detailed Implementation

[0059] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Furthermore, a brief explanation of the orientations involved in the following specific embodiments is provided: the directions or positional relationships indicated by "up," "down," "left," "right," "front," and "back" mentioned in the embodiments refer to the orientations or positional relationships shown in the accompanying drawings.

[0060] For polymer-based composite compression fixtures or specimens, it is impossible to guarantee the consistency of the position of specimens within the same batch during testing. In particular, tests such as static indentation require high alignment between fixtures, specimens, and machines, making it essential to take appropriate measures to ensure alignment.

[0061] This invention relates to a limiting device for the compression properties of composite materials. The limiting device is installed in the middle position of the lower pressure plate on a compression testing machine. The limiting device positions the test specimen, which is one or a combination of non-metallic material compression test fixtures and specimens. The limiting device of this invention can be widely used in standard or non-standard compression tests of polymer-based composite materials. On the one hand, it can improve the stability and accuracy of the test, and on the other hand, it can improve the efficiency of fixture loading and unloading.

[0062] Specifically, the limiting device is mainly made of metal and requires an HRC of 45 or higher. The limiting device is cross-shaped and includes at least a base 1, four limiting blocks 2 set on the base, and a linkage assembly 3 connected to the limiting blocks. The base has intersecting X-axis and Y-axis slide rails. Two limiting blocks limit the test piece on the X-axis slide rail, and two limiting blocks limit the test piece on the Y-axis slide rail. The limiting blocks are mainly used for centering. The linkage assembly controls the movement of the limiting blocks to ensure accurate centering and limiting of the test piece.

[0063] Specifically, the X-axis slide rail and the Y-axis slide rail are located at the upper end of the base, and the X-axis slide rail and the Y-axis slide rail are perpendicular to each other. Two limiting blocks are symmetrically arranged on the X-axis slide rail about the center of the X-axis slide rail, and two limiting blocks are symmetrically arranged on the Y-axis slide rail about the center of the Y-axis slide rail. The limiting blocks 2 slide on the X-axis slide rail and the Y-axis slide rail, and the limiting blocks can achieve omnidirectional positioning of the test piece. This arrangement avoids the complexity of the operation of scribing the test piece during the experiment, and also improves the accuracy of the test results of the same batch of test pieces.

[0064] Specifically, the base 1 includes at least a chassis 11, and the X-axis slide rail and the Y-axis slide rail are both configured as groove structures 111 of the chassis 11. The groove structure is used to limit the movement of the limiting block.

[0065] Specifically, the chassis 11 is cross-shaped, with the long side of the chassis being L1, where L1 ≥ 60 mm, and the short side of the chassis being L2, where L2 ≥ 500 mm. The chassis 11 mainly serves to support the fixture and the sample. A circular beam 112 is set in the middle of the chassis, which mainly serves as a reinforcing beam and support. Considering the standard compression fixture size, the diameter of the circular beam in the middle of the chassis should be ≥ 300 mm.

[0066] Specifically, the length of the limiting block should be equal to the width of the circular beam of the chassis, with a value range of 100mm to 120mm, and the width and height of the limiting block should be controlled between 40mm and 60mm.

[0067] Preferably, the X-axis slide rail includes a first X-axis groove 1111 and a second X-axis groove 1112, the first X-axis groove 1111 and the second X-axis groove 1112 are arranged in parallel, the Y-axis slide rail includes a first Y-axis groove 1113 and a second Y-axis groove 1114, the first Y-axis groove 1113 and the second Y-axis groove 1114 are arranged in parallel, and the interval between the first X-axis groove and the second X-axis groove is equal to the distance between the first Y-axis groove and the second Y-axis groove.

[0068] Specifically, the base 1 also includes a flange connecting plate 12 and a clamping column 13. The flange connecting plate 12 is used to connect the base 11 and the clamping column 13. The clamping column 13 has a cylindrical structure and is used to connect the testing machine. The flange connecting plate 12 is connected to the lower end of the base 11.

[0069] More specifically, the chassis 11 is provided with a first threaded hole 113, which is located at the lower end of the chassis. The flange connecting plate 12 is provided with a settlement hole 121. The flange connecting plate 12 and the chassis 11 are connected by bolts screwed into the settlement hole 121 and the first threaded hole 113.

[0070] More specifically, the settlement hole 121 is arranged in a circle with the center of the flange connecting plate, and the first threaded hole 113 is arranged in a circle with the center of the circular beam 112 as the center. Preferably, the settlement hole 121 and the first threaded hole 113 are arranged correspondingly, and each is set to 4.

[0071] Specifically, the clamping column 13 is connected to the flange connecting plate 12. The flange connecting plate 12 is provided with a second threaded hole 122, which is located at the center of the flange connecting plate 12. The clamping column is inserted into the second threaded hole 122 and connected to the flange connecting plate 12. The diameter of the clamping column should be between 25mm and 50mm so as to ensure the stability of the chassis while clamping.

[0072] Specifically, this limiting device can be combined with different testing machines to select matching clamping columns. Preferably, the clamping column 13 includes a first cylinder 131 and a second cylinder 132. The diameter of the first cylinder 131 is slightly smaller than the diameter of the second cylinder 132. The outer circumference of the first cylinder 131 is provided with threads, and the thread length is more than 20mm. The first cylinder 131 is inserted into the second threaded hole 122 of the flange connecting plate, and the second cylinder 132 is connected to the testing machine.

[0073] Specifically, the limiting device further includes a fixed slider 4, which is connected to the limiting block 2. The fixed slider 4 is located in the groove structure 111 of the X-axis slide rail and the Y-axis slide rail, and is used to fix the limiting block 2.

[0074] Preferably, the lower end of any limiting block on the X-axis slide rail is connected to two fixed sliders, which are located in the first X-axis groove 1111 and the second X-axis groove 1112, respectively. Similarly, the lower end of any limiting block on the Y-axis slide rail is connected to two fixed sliders, which are located in the first Y-axis groove 1113 and the second Y-axis groove 1114, respectively.

[0075] Specifically, a track block 21 is provided at the lower end of the limiting block 2. The track block 21 has a downward protruding structure along the bottom end of the limiting block. The number of track blocks is the same as that of the fixed slider. Preferably, there are two track blocks and two fixed sliders. The track blocks are set in the groove structure to ensure that the limiting block can only move along the track direction. The track block 21 is connected to the fixed slider 4 by bolts. The track block restricts the movement direction of the limiting block.

[0076] Specifically, the limiting block 2 is provided with a third threaded hole 22, which passes through the upper end of the limiting block and the track block 21. The fixed slider is provided with a fifth threaded hole 41. The track block 21 is connected to the fixed slider 4 by bolts passing through the third threaded hole 22 and the fifth threaded hole 41. This arrangement is used to fix the limiting block. By tightening the bolts, the fixed slider can be kept in close contact with the convex track wall, increasing the friction and thus limiting the movement of the limiting block.

[0077] Specifically, the groove in the groove structure 111 is a "convex structure". The convex structure includes a notch 1115 and a U-shaped groove 1116. The fixed slider is located in the U-shaped groove 1116 and the track block is located in the notch. When the limiting block moves, the fixed slider moves in the U-shaped groove and drives the track block to move at the notch. The connection between the U-shaped groove and the notch is set as a limiting plate 1117. When the limiting block needs to be fixed, the bolts of the limiting plate 1117 can be tightened to make the fixed slider abut against the limiting plate 1117, and finally fix the limiting block.

[0078] Specifically, the limiting block 2 is provided with a support column 24, which is used to connect the connecting rod assembly 3. The support column 24 is located at the upper end of the limiting block, and the support column is located at the middle of the long side of the limiting block and close to the center of the chassis. Preferably, the support column is a cylindrical structure that protrudes upward on the upper surface of the limiting block.

[0079] Specifically, the limiting device further includes a limiting rod 5, which passes through the limiting block 2 and is parallel to the track block. The limiting rod 5 can achieve secondary limiting of the contact between the clamp or the sample.

[0080] More specifically, the limiting block 2 is provided with a first through hole 23, and the limiting rod 5 is inserted into the first through hole 23. The first through hole can be designed as a round hole or a square hole. If there is no requirement for the rotation of the limiting rod, a round hole can also be used. The side length of the square hole or the diameter of the round hole should be between 10mm and 15mm. This provides stable support for the limiting rod while avoiding an excessively large opening. Preferably, the first through hole 23 is a square hole. The square hole is used to limit the movement of the limiting rod. The first through hole 23 passes through the long side of the limiting block 2 and is parallel to the track block. The limiting rod is connected to the limiting block through the square hole. When the limiting block is fixed, the limiting rod can still move to complete a secondary limiting.

[0081] More specifically, the limiting block is provided with a fourth threaded hole 25. The fourth threaded hole is mainly used to restrict the movement of the limiting rod. By screwing the bolt into the fourth threaded hole 25, the bottom of the bolt contacts the limiting rod. As the bolt goes in more, the pressure on the limiting rod increases, and the movement of the limiting rod is restricted.

[0082] More specifically, the limiting rod 5 includes a top plate 51 and a sliding arm 52. The top plate 51 is connected to the sliding arm 52. The top plate 51 contacts the fixture or the sample. Preferably, the sliding arm 52 is a cuboid structure. The sliding arm 52 can ensure that the limiting rod 5 can move in the first through hole 23. The top plate 51 contacts the fixture or the sample to achieve secondary limiting.

[0083] Specifically, the limiting device further includes a connecting rod assembly 3 for connecting adjacent limiting blocks, thereby ensuring that adjacent limiting blocks move simultaneously. The connecting rod assembly 3 is used to control the accurate movement of the limiting block 2 to achieve centering. The connecting rod assembly is detachably connected to the limiting block. The connecting rod assembly 3 includes a first connecting rod 31, a second connecting rod 32, and a washer 33. The first connecting rod 31 and the second connecting rod 32 have the same length. The first connecting rod 31 and the second connecting rod 32 are detachably connected to the support column. The washer is set at the contact point between the connecting rod assembly and the limiting block to ensure that the position of the connecting rod assembly is horizontal.

[0084] Preferably, the length of the first connecting rod and the second connecting rod should be ≥300mm in order to complete the limiting of the small sample, and the width of the first connecting rod and the second connecting rod is recommended to be 10mm.

[0085] Preferably, the first connecting rod 31 is located on the second connecting rod 32. When one end of the first connecting rod 31 and the second connecting rod 32 are connected to the support column 24 at the same time, there is no need to add a shim 33. When one end of the first connecting rod 31 and the second connecting rod 32 are connected to the support column 24 separately, a shim 33 needs to be set at one end of the first connecting rod 31. This setting ensures that the first connecting rod and the second connecting rod always remain parallel.

[0086] Preferably, the thickness of the first connecting rod is the same as the thickness of the second connecting rod, and the thickness of the gasket is the same as the thickness of the first connecting rod and the second connecting rod. The thickness of the first connecting rod, the second connecting rod, and the gasket are all 5mm to 8mm, which is used to ensure the consistency of the distance between the limiting blocks.

[0087] Preferably, the four limiting blocks are A limiting block 26, B limiting block 27, C limiting block 28, and D limiting block 29. Limiting blocks A and C are located on the groove structure of the Y-axis slide rail, and limiting blocks B and D are located on the groove structure of the X-axis slide rail.

[0088] Preferably, the first connecting rod 31 has a second through hole 311 and a third through hole 312 at both ends, the second connecting rod 32 has a fourth through hole 321 and a fifth through hole 322, and the gasket 33 has a sixth through hole 331. The support column on the A limiting block passes through the second through hole 311 and the fourth through hole 321 in sequence to connect the first connecting rod and the second connecting rod to the limiting block. The support column on the B limiting block passes through the fifth through hole 322 to connect the second connecting rod to the limiting block. The support column on the D limiting block passes through the sixth through hole and the third through hole 312 on the gasket in sequence to connect the first connecting rod to the limiting block. This arrangement allows the simultaneous movement of the B and D limiting blocks by moving the A limiting block.

[0089] When it is necessary to move the A limit block and the C limit block, simply remove the first connecting rod and reconnect it to the B limit block and the C limit block.

[0090] Preferably, the second, third, fourth, fifth, and sixth through holes are all circular holes, with the corresponding diameters being the same as the diameter of the support column. The diameter of the circular holes is between 2mm and 4mm.

[0091] A limiting method using the aforementioned limiting device enables precise centering of the test piece. The limiting method includes three limiting modes: Mode 1 involves four limiting blocks moving to limit the movement while the limiting rods on the limiting blocks remain stationary; Mode 2 involves two coaxial limiting blocks moving to limit the movement first, followed by the limiting rods on the other two limiting blocks moving to limit the movement; and Mode 3 involves four limiting blocks moving to limit the movement first, followed by the limiting rods on the limiting blocks moving to limit the movement.

[0092] Specifically, the first method mainly limits the test piece, which is either a fixture or a sample, and includes the following steps:

[0093] S1: Place the test piece on the chassis, connect the first connecting rod 31 to the A limiting block and the D limiting block, and connect the second connecting rod to the A limiting block and the B limiting block;

[0094] S2: Move limit block A, limit block B and limit block D simultaneously until limit block B and limit block D contact the test piece at the same time, then fix limit block B and limit block D. Since the dimensions of the first connecting rod 31 and the second connecting rod 32 are the same, the distance between limit block B and limit block D and the center can be kept consistent during the movement.

[0095] S3: When moving limit blocks A and C, simply remove the first connecting rod and reconnect it to limit blocks B and C. The connection relationship of the second connecting rod remains unchanged. As limit block B moves, limit blocks A and C move simultaneously until they contact the test piece. Fix limit blocks A and C, remove the first and second connecting rods, and finally move limit block B to contact the test piece. In this setup, the movement of limit block B ensures the consistency of the distance between limit blocks A and C and the center position, aligning the test piece. This ensures that the test piece is in the same position in subsequent repeatable tests.

[0096] Specifically, in method two, the test piece used is either a fixture or a sample, and the specific steps are as follows:

[0097] S1: Place the test piece on the chassis, connect the first connecting rod 31 to the A limiting block and the D limiting block, and connect the second connecting rod to the A limiting block and the B limiting block;

[0098] S2: Move limit block A, limit block B and limit block D simultaneously until limit block B and limit block D contact the test piece at the same time, then fix limit block B and limit block D. Since the dimensions of the first connecting rod 31 and the second connecting rod 32 are the same, the distance between limit block B and limit block D and the center can be kept consistent during the movement.

[0099] S3: By moving the limiting rods on limit block A and limit block C, the scale on limit rod A is made consistent with the scale on limit rod C. At the same time, the limiting rods on limit block A and limit block C are both abutting against the test piece. By fixing the limiting rods on limit block A and limit block C, it can be ensured that the test piece is in the same position in subsequent repeatability tests.

[0100] When the test piece used in Method 3 is either a fixture or a specimen, the following steps are taken;

[0101] S1: Place the test piece on the chassis, connect the first connecting rod 31 to the A limiting block and the D limiting block, and connect the second connecting rod to the A limiting block and the B limiting block;

[0102] S2: Move limit block A, limit block B and limit block D simultaneously until limit block B and limit block D are at a certain distance from the test piece. Fix limit block B and limit block D. Since the dimensions of the first connecting rod 31 and the second connecting rod 32 are the same, the distance between limit block B and limit block D and the center can be kept consistent during the movement.

[0103] S3: When moving limit blocks A and C, the connection relationship of the first connecting rod remains unchanged. Only the second connecting rod needs to be removed. Limit block D remains stationary. Reconnect the second connecting rod to limit blocks C and D. Limit block C moves. At this time, limit blocks A and C are aligned with the center of the chassis. Fix limit block C, remove the first and second connecting rods, and place the test piece in the middle of the four limit blocks.

[0104] S4: Push the limiting rods on limit block A and limit block C to make their scales consistent. Then push the limiting rods on limit block B and limit block D to make their scales consistent, thus completing the centering and limiting of the test piece.

[0105] When the test piece used in Method 3 is a combination of a fixture and a specimen, the following steps are taken;

[0106] S1: Place the fixture on the chassis, connect the first connecting rod 31 to the A limit block and the D limit block, and connect the second connecting rod to the A limit block and the B limit block;

[0107] S2: Move limit block A, limit block B and limit block D simultaneously until limit block B and limit block D contact the test piece at the same time, then fix limit block B and limit block D. Since the dimensions of the first connecting rod 31 and the second connecting rod 32 are the same, the distance between limit block B and limit block D and the center can be kept consistent during the movement.

[0108] S3: When moving limit blocks A and C, simply remove the first connecting rod and reconnect the first connecting rod to limit blocks B and C. The connection relationship of the second connecting rod remains unchanged. As limit block B moves, limit blocks A and C move simultaneously until limit blocks A and C contact the test piece. Fix limit blocks A and C, remove the first and second connecting rods, and finally move limit block B to contact the test piece.

[0109] S4: Place the sample in the fixture. Move the limiting rods of limit block A and limit block C to make the scales on the limiting rods of limit block A and limit block C consistent. Move the limiting rods of limit block B and limit block D to make the scales on the limiting rods of limit block B and limit block D consistent. This limits the sample and ensures that the test piece is in the same position in subsequent repeatability tests.

[0110] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.

[0111] Example 1

[0112] This limiting device limits the limiting fixture: ASTM D6641 standard is mainly used to test the compressive properties of polymer-based composite materials, and its fixture form is as follows... Figure 20 As shown, during the test, the limiting device is placed in the middle of the lower pressure plate of the testing machine. This limiting device is used, employing the limiting method described in Method Two above. Figure 21 As shown, by using a combination of limiting rods and limiting blocks, the position of the fixture can be positioned, ensuring the consistency of position for subsequent samples in the same batch.

[0113] Example 2

[0114] The limiting device limits the tooling and the sample: such as Figure 22As shown in ASTM D6264, the edge-supported fixture for static indentation testing consists of a flat plate with a 125mm diameter opening. The standard specifies that during specimen installation, the center of the specimen must be aligned with the center of the fixture opening and the center line of the indenter. If individual specimens are to be loaded at intervals, alignment marks should be made on the specimen and fixture to maintain the original alignment. This limiting device allows for initial positioning of four limiting blocks according to the size of the static indentation fixture. The static indentation test specimen is then placed on the fixture, its center point marked, and the indenter lowered to the upper surface of the center point, aligned vertically with it. The telescopic limiting rod is adjusted to contact the specimen, and its position is fixed. This ensures consistency of the center point for subsequent tests on specimens from the same batch. Additionally, dimensional markings can be made on the telescopic limiting rods. During specimen limiting, the telescopic extension of the limiting rods on blocks A and C, and blocks B and D, must be consistent.

[0115] Example 3

[0116] This invention provides a limiting device for testing the compressive properties of composite materials, wherein the dimensions of the relevant structures in the limiting device are as follows: Figure 23-28 As shown, all dimensions are in mm.

[0117] Specifically, a limiting device for testing the compressive properties of composite materials includes a circular beam with a radius of 50 mm and a height of 30 mm, an X-axis slide rail with a length of 600 mm, a width of 120 mm, and a height of 10 mm, a Y-axis slide rail with a length of 700 mm, a width of 120 mm, and a depth of 5 mm, a U-shaped groove with a width of 20 mm, and a notch with a width of 10 mm and a depth of 9 mm.

[0118] Specifically, the flange connecting plate has a radius of 60mm and a thickness of 20mm, the settlement hole has a radius of 9.5mm and a depth of 12mm, and the second threaded hole has a diameter of 30mm.

[0119] Specifically, the height of the first cylinder held is 20mm, the height of the second cylinder is 60mm, and the diameter of the second cylinder is 30mm.

[0120] Specifically, the length of the limiting block is 120mm, the width of the limiting block is 45mm, the depth of the track block is 5mm, the width of the track block is 10mm, and the length and width of the square hole are 10mm respectively.

[0121] Specifically, the top plate is 40mm long and 20mm wide, and the sliding arm is 200mm long, 10mm wide, and 10mm high.

[0122] Specifically, the fixed slider has a length of 40mm, a thickness of 8mm, and a width of 18mm.

[0123] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A limiting device for testing the compressive properties of composite materials, wherein the limiting device centers and limits the test specimen, characterized in that, The limiting device includes at least a base (1), four limiting blocks (2) disposed on the base (1), a connecting rod assembly (3) connected to the limiting blocks (2), a fixed slider (4), and a limiting rod (5). The base (1) is provided with intersecting X-axis slide rails and Y-axis slide rails, wherein two limiting blocks (2) limit the test piece on the X-axis slide rail and two limiting blocks (2) limit the test piece on the Y-axis slide rail. The connecting rod assembly (3) controls the movement of the limiting blocks (2) to ensure that the test piece is accurately centered and limited. The base (1) includes at least a chassis (11), a flange connecting plate (12), and a clamping column (13). The chassis (11) is connected to the flange connecting plate (12), and the flange connecting plate (12) is connected to the clamping column (13). The support column (13) is connected; the X-axis slide rail and the Y-axis slide rail are both set as the groove structure (111) of the chassis (11); the lower end of the limiting block (2) is provided with a track block (21), and the track block (21) is connected to the fixed slider (4); the fixed slider (4) and the track block (21) are both located in the groove structure (111); the groove in the groove structure (111) is a convex structure, which includes a notch (1115) and a U-shaped groove (1116). The fixed slider is located in the U-shaped groove (1116), the track block (21) is located in the notch, and the connection between the U-shaped groove and the notch is set as a limiting plate (1117). When the limiting block needs to be fixed, tighten the bolts to make the fixed slider abut against the limiting plate (1117); the limiting rod (5) passes through the limiting block (2) and is parallel to the fixed slider (4); the limiting block (2) is provided with a first through hole (23) and a fourth threaded hole (25), the limiting rod (5) is inserted into the first through hole (23), and the limiting block (2) is fixed to the limiting rod (5) by screwing the bolt into the fourth threaded hole (25), the limiting rod (5) realizes the secondary limiting of the sample; the limiting block (2) is provided with a support column (24), the support column (24) is located at the upper end of the limiting block (2), and the support column (24) is used to connect the connecting rod assembly (3); the The linkage assembly (3) includes a first connecting rod (31), a second connecting rod (32), and a washer (33). The first connecting rod (31) and the second connecting rod (32) have the same length. The first connecting rod (31) and the second connecting rod (32) are detachably connected on the support column. The first connecting rod (31) is located on the second connecting rod (32). When one end of the first connecting rod (31) and the second connecting rod (32) are simultaneously connected to the support column (24) on the limiting block, the other end of the first connecting rod (31) is fixed on the support column of the adjacent limiting block, and a washer (33) is provided. The other end of the second connecting rod (32) is connected to the support column (24) of the limiting block, which is coaxial with the first connecting rod.

2. The limiting device according to claim 1, characterized in that, The limiting block (2) is provided with a third threaded hole (22), which extends from the upper end of the limiting block (2) to the track block (21). The fixed slider (4) is provided with a fifth threaded hole (41), and the track block (21) is connected to the fixed slider (4) by bolts screwed into the third threaded hole (22) and the fifth threaded hole (41).

Images