Clamp for compression test of composite material flat-plate-shaped test piece

Abstract

The utility model provides a clamp for a compression test of a composite material tabulate test piece, which comprises an upper pressing assembly and a lower pressing assembly, the upper pressing assembly comprises a first upper clamping plate, a second upper clamping plate and an upper pressing plate, and the upper pressing plate is connected to the upper parts of the first upper clamping plate and the second upper clamping plate; the lower pressing assembly comprises a first lower clamping plate, a second lower clamping plate and a lower pressing plate, the lower pressing plate is connected to the lower portions of the first lower clamping plate and the second lower clamping plate, and the sizes of the first upper clamping plate, the second upper clamping plate and the upper pressing plate in the first direction parallel to the width direction of the test piece are larger than the width of the test piece; the sizes of the first lower clamping plate, the second lower clamping plate and the lower pressing plate in the first direction are greater than the width of the test piece. According to the scheme, a transverse deformation space can be reserved for the end part of the test piece when the test piece is subjected to a compression test, and free deformation of the test piece is allowed, so that stress concentration of an interface of the test piece and the clamp can be reduced, and test failure caused by advanced damage of the test piece is avoided.

Description

Fixtures for compression testing of flat composite specimens Technical Field

[0001] This utility model relates to the field of composite material fuselage panel testing technology, and in particular to a fixture for compression testing of flat composite material specimens. Background Technology

[0002] Existing compression tests for large-sized, high-load composite fuselage panels generally use the ASTM D7137 test fixture. However, since this fixture was originally designed for compression testing of smaller specimens, it presents the following problems when used for flat plate compression test specimens, such as fuselage panel radius compression tests, which involve larger dimensions, high test loads, and require failure within the test area:

[0003] 1. Stability issues: During compression, the R-angle test specimen of the composite fuselage panel may become unstable, leading to unexpected failure modes and test failure.

[0004] 2. End-of-span crushing problem: For plate tests with large dimensions and test loads, similar to the R-angle test specimens of composite fuselage panels, the ends of the test specimen are generally fixed with ASTM 7137 or with potted end-type fixed constraints (restraining the thickness and width deformation of the test specimen ends). During the test, the Poisson effect in the unrestrained structure causes in-plane lateral deformation of the test specimen, and the lateral constraints at both ends lead to inconsistent deformation at the constraint interface, resulting in local stress concentration. The test specimen splits prematurely at this point, leading to test failure.

[0005] 3. The fixture is fixed into a non-movable whole by fasteners. Different fixtures need to be manufactured for test pieces of different lengths, widths and thicknesses, resulting in low flexibility and high cost.

[0006] Therefore, there is a need to provide a fixture for compression testing of flat composite specimens to at least partially solve the above problems. Summary of the Invention

[0007] The fixture for compression testing of flat composite material specimens proposed in this utility model includes:

[0008] An upper pressure assembly includes a first upper clamping plate, a second upper clamping plate, and an upper pressure plate. The first and second upper clamping plates are arranged parallel to each other on opposite sides of the clamp and a gap is formed between them, allowing a specimen to be inserted between them and clamped from both sides. The upper pressure plate is connected to the upper parts of the first and second upper clamping plates and is configured to abut against the upper end face of the specimen.

[0009] A pressing assembly includes a first lower clamping plate, a second lower clamping plate, and a pressing plate. The first and second lower clamping plates are arranged parallel to each other on opposite sides of the clamp and a gap is formed between them, allowing the specimen to be inserted between them and clamped from both sides. The pressing plate is connected to the lower part of the first and second lower clamping plates and is configured to abut against the lower end face of the specimen.

[0010] Wherein, the dimensions of the first upper clamping plate, the second upper clamping plate, and the upper pressure plate in a first direction parallel to the width direction of the specimen are greater than the width of the specimen, and the dimensions of the first lower clamping plate, the second lower clamping plate, and the lower pressure plate in the first direction are greater than the width of the specimen.

[0011] Preferably, the upper pressure assembly further includes a support frame having an inverted U-shaped cross-sectional shape and forming an accommodating space therein. The first upper clamping plate and the second upper clamping plate are connected to the support frame on both sides of the accommodating space by fasteners, and the upper pressure plate is connected to the support frame on the top of the accommodating space by fasteners.

[0012] Preferably, the first upper clamp and the second upper clamp are configured to adjust the distance between them.

[0013] Preferably, the top of the support frame has a first elongated guide hole extending in a second direction parallel to the thickness direction of the specimen, and the upper pressure plate has a second elongated guide hole extending parallel to the first elongated guide hole at a position corresponding to the first elongated guide hole. The support frame, the upper pressure plate, and the first upper clamping plate are connected together by fasteners extending through the first elongated guide hole and the second elongated guide hole, respectively.

[0014] The upper pressure assembly further includes a plurality of first adjusting bolts, which are respectively disposed on two sides of the support frame, extend through the support frame into the receiving space and abut against the first upper clamping plate and the second upper clamping plate.

[0015] Preferably, the pressing assembly further includes mounting handles, which are respectively disposed on two sides of the support frame opposite to each other along a second direction parallel to the thickness direction of the specimen; and / or

[0016] The pressure assembly also includes a scale, which is fixed to at least one of the two end faces of the support frame that are opposite to each other along the first direction.

[0017] Preferably, the clamp further includes a support base, the support base includes a base body, the lower pressure plate is connected to the base body above the base body by fasteners, and the first lower clamping plate and the second lower clamping plate are connected to the base body above the lower pressure plate by fasteners.

[0018] Preferably, the first lower clamp and the second lower clamp are configured to adjust the distance between them.

[0019] Preferably, the first lower clamping plate and the second lower clamping plate are formed with a third long guide hole extending in a second direction parallel to the thickness direction of the specimen.

[0020] The pressing assembly further includes a plurality of second adjusting bolts and a first support plate and a second support plate respectively disposed on the outer side of the first lower clamping plate and the second lower clamping plate. The plurality of second adjusting bolts are respectively disposed on the upper end of the first support plate and the second support plate, and extend through the first support plate and the second support plate to abut against the first lower clamping plate and the second lower clamping plate. The lower end of the first support plate and the second support plate is fastened to the base body.

[0021] Preferably, the clamp further includes a main body fixing assembly, which includes a first cover plate and a second cover plate respectively disposed on the front and back sides of the specimen, a plurality of first transverse supports and a plurality of second transverse supports, a plurality of first longitudinal supports and a plurality of second longitudinal supports, the plurality of first transverse supports and the plurality of first longitudinal supports being arranged perpendicularly to each other, the plurality of second transverse supports and the plurality of second longitudinal supports being arranged perpendicularly to each other, the first cover plate being connected to the plurality of first transverse supports and the plurality of first longitudinal supports on the outside of the plurality of first transverse supports and the plurality of first longitudinal supports, and the second cover plate being connected to the plurality of second transverse supports and the plurality of second longitudinal supports on the outside of the plurality of second transverse supports and the plurality of second longitudinal supports.

[0022] Preferably, the first cover plate and the second cover plate are respectively connected to the first transverse support and the second transverse support by a third adjusting bolt, and the first cover plate and the second cover plate are respectively connected to the first longitudinal support and the second longitudinal support by a fourth adjusting bolt. The first cover plate and the second cover plate are respectively provided with a fourth long guide hole for the passage of the third adjusting bolt, and the fourth long guide hole extends in a third direction parallel to the length direction of the specimen.

[0023] Preferably, the clamp further includes a side support assembly, which includes a first support member and a second support member located on opposite sides of the main body fixing assembly along the first direction. The two ends of the first cover plate and the two ends of the second cover plate are respectively connected to the first support member and the second support member by a fifth adjusting bolt. The first cover plate and the second cover plate are also respectively provided with a fifth long guide hole extending along the first direction for the fifth adjusting bolt to pass through.

[0024] Preferably, the main body fixing assembly includes a pair of first cover plates and a pair of second cover plates spaced apart along the third direction.

[0025] Preferably, a portion of the first support member and the second support member has a U-shaped cross-sectional shape. The side support assembly further includes a first blade clamping member and a second blade clamping member disposed within the U-shaped structure of each of the first and second support members. The first blade clamping member is connected to the first support member by an adjusting bolt, and the second blade clamping member is connected to the second support member by an adjusting bolt. The first blade clamping member and the second blade clamping member each include a pair of blade clamping portions, which are configured to clamp the specimen from both sides.

[0026] The specimen has R-angle openings on both sides opposite to each other along the first direction, and the side support assembly does not have the blade clamping part at the position corresponding to the R-angle opening.

[0027] Preferably, the clamp further includes an additional support assembly, which includes a first additional support and a second additional support located on the outside of the first support and the second support, respectively. The first additional support and the second additional support are connected to the first support and the second support by fasteners, and both the first additional support and the second additional support are connected to the support base. The first additional support and the second additional support are each constructed as a triangular structure, and the first additional support and the second additional support are each provided with a weight reduction opening.

[0028] Preferably, the support base further includes a first base slider and a second base slider disposed on the base body. The first base slider and the second base slider are spaced apart along the first direction. The specimen can be disposed between the first base slider and the second base slider. The first base slider is fixedly connected to the first support member and the first additional support member, and the second base slider is fixedly connected to the second support member and the second additional support member.

[0029] The first base slider and the second base slider are configured to slide along the first direction on the base body, so that the gap between the first base slider and the second base slider can be adjusted.

[0030] Preferably, the support base further includes guide blocks disposed on both sides of each of the first and second base sliders, the guide blocks on both sides being spaced apart along the thickness direction of the specimen, and the guide blocks being fixedly connected to the base body.

[0031] Preferably, the contact surfaces between the first upper clamping plate and the second upper clamping plate and the upper pressure plate have no chamfer on the side closest to the specimen, and / or

[0032] The contact surfaces between the first and second lower clamping plates and the lower pressure plate have no chamfer on the side closest to the specimen.

[0033] The fixture for compression testing of composite flat specimens according to the above scheme has the following beneficial effects:

[0034] (1) By increasing the length of the clamping plate and pressure plate of the upper and lower compression components of the compression test fixture to be greater than the width of the specimen, the side of the entire specimen can be unrestrained, thus leaving space for lateral deformation at the end of the specimen, allowing it to deform freely in the plane due to the Poisson effect, thereby reducing the stress concentration at the interface between the specimen and the clamping plate and avoiding premature failure of the specimen and test failure.

[0035] (2) By setting long guide holes and adjusting bolts on the first cover plate and the second cover plate respectively, the height of the transverse support and the position of the longitudinal support can be easily adjusted, so that it can provide customizable out-of-plane support on the surface of the specimen according to the size of different specimens, load type, patch arrangement scheme, etc. This scheme can not only improve the support efficiency, but also avoid interference with the strain gauge, thus meeting a variety of test requirements. Attached Figure Description

[0036] To better understand the above and other objects, features, advantages, and functions of this utility model, reference can be made to the preferred embodiments shown in the accompanying drawings. The same or similar reference numerals in the drawings refer to the same or similar parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate the preferred embodiments of this utility model and do not limit the scope of this utility model in any way; the parts in the drawings are not drawn to scale.

[0037] Figure 1 is a perspective view of a compression test fixture according to a preferred embodiment of the present invention, wherein a flat composite material specimen to be tested is assembled in the compression test fixture.

[0038] Figures 2 and 3 are three-dimensional schematic diagrams of the upper pressure assembly of the compression test fixture in Figure 1, viewed from different perspectives.

[0039] Figure 4 is an exploded view of the support frame and upper pressure plate of the upper pressure assembly shown in Figures 2 and 3.

[0040] Figure 5 is a top view of the first and second upper pressure plates and the specimen clamped between them.

[0041] Figure 6 is a schematic diagram of the assembly of the compression test fixture and the base frame in Figure 1.

[0042] Figure 7 is another perspective view of a compression test fixture according to a preferred embodiment of the present invention, wherein one of the cover plates is in a separated state in order to clearly show the structure of the transverse support and the longitudinal support.

[0043] Figure 8 is another perspective view of a compression test fixture according to a preferred embodiment of the present invention, wherein the upper pressure component is omitted. Detailed Implementation

[0044] The compression test fixture according to a preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the following description is merely a preferred embodiment of the present invention, and those skilled in the art can conceive of other ways to implement the present invention based on the preferred embodiments; such other ways also fall within the scope of the present invention.

[0045] First, it should be noted that the directional and positional terms used in this utility model should be understood as relative directions and positions, rather than absolute directions and positions.

[0046] The following description will mainly refer to Figures 1-8 to provide a detailed description of the compression test fixture 100 for a composite material flat specimen 200 (hereinafter referred to as "the specimen 200") according to a preferred embodiment of the present invention.

[0047] As shown in Figure 1, the compression test fixture 100 mainly includes an upper pressure assembly 110 and a lower pressure assembly 120, a support base 130, a main body fixing assembly 140, a side support assembly 150, and an additional support assembly 160. These will be described in detail below.

[0048] Upper pressure assembly and lower pressure assembly

[0049] The upper pressure assembly 110 and the lower pressure assembly 120 are mainly used to clamp the specimen 200 from above and below, respectively, and will be described in detail below. It should be noted that, as mentioned herein, "the front side of the specimen" refers to the side with the larger surface area, "the back side of the specimen" refers to the side of the specimen opposite to its front side, "the front side of the clamp" refers to the side of the clamp corresponding to the front side of the specimen, and "the back side of the clamp" refers to the side of the clamp corresponding to the back side of the specimen. "First direction" refers to a direction parallel to the width direction of the specimen, "second direction" refers to a direction parallel to the thickness direction of the specimen, and "third direction" refers to a direction parallel to the length direction of the specimen.

[0050] As shown in Figures 1-4, the upper pressing assembly 110 mainly includes a support frame 119, a first upper clamping plate 111, a second upper clamping plate 112, and an upper pressing plate 113. The support frame 119 is the main supporting structure of the upper pressing assembly 110, responsible for connecting the various functional components. The cross-section of the support frame 119 is inverted U-shaped, creating an internal accommodating space. The first upper clamping plate 111 and the second upper clamping plate 112 are located on either side of this accommodating space and are connected to the top wall of the support frame 119 via fasteners. The upper pressing plate 113 is located at the top of the accommodating space, above the first upper clamping plate 111 and the second upper clamping plate 112. The upper pressing plate 113 is connected to the top wall of the support frame 119 via the aforementioned fasteners. In other words, the first upper clamping plate 111, the second upper clamping plate 112, and the upper pressing plate 113 are connected to the support frame 119 via shared fasteners. In this way, the upper pressing plate 113 is also connected to the first upper clamping plate 111 and the second upper clamping plate 112. The first upper clamping plate 111 and the second upper clamping plate 112 are arranged parallel to each other on the front and back sides of the clamp 100, with a gap between them, so that the specimen 200 can be inserted between them and clamped from both sides of the specimen 200. The upper pressure plate 113 is mainly used to abut against the upper end face of the specimen 200 to facilitate the transmission of compressive load.

[0051] In a preferred embodiment, the gap between the first upper clamping plate 111 and the second upper clamping plate 112 in the second direction can be adjusted. As shown in Figures 1 and 4, a plurality of first elongated guide holes 114 are formed on the top of the support frame 119, and a plurality of second elongated guide holes 115 are provided on the upper pressure plate 113 at positions corresponding to the first elongated guide holes 114. Both the first elongated guide holes 114 and the second elongated guide holes 115 extend along the second direction. Fasteners extend successively through the first elongated guide holes 114 and the second elongated guide holes 115 and are then fastened to the first upper clamping plate 111 and the second upper clamping plate 112. The first upper clamping plate 111 and the second upper clamping plate 112 can be shifted along the elongated guide holes, thereby adjusting the gap between the first upper clamping plate 111 and the second upper clamping plate 112 in the second direction. As shown in Figure 1, the upper pressure assembly 110 also includes a plurality of first adjusting bolts 116. The plurality of first adjusting bolts 116 are respectively disposed on two opposite sides of the support frame 119 along the second direction (that is, on the two side walls of the U-shaped profile), and extend through the support frame 119 into the receiving space and abut against the first upper clamping plate 111 and the second upper clamping plate 112. The first adjusting bolts 116 can be used to adjust the position of the first upper clamping plate 111 and the second upper clamping plate 112 to accommodate specimens 200 of different thicknesses, thereby enhancing the versatility of the compression test fixture 100.

[0052] Referring again to Figure 1, the pressing assembly 110 further includes mounting handles 117, which are respectively disposed on two opposite sides of the support frame 119 along the second direction. That is, the mounting handles 117 are mounted on the same side as the first adjusting bolt 116, and are positioned above the first adjusting bolt 116. The mounting handles 117 are directly connected to the support frame 119 by screw fastening, facilitating subsequent installation or movement of the pressing assembly 110 by gripping the mounting handles 117. In the illustrated embodiment, the pressing assembly 110 includes four mounting handles 117, with two on each side of the support frame 119. It is understood that in other embodiments not shown, the pressing assembly 110 may include a different number of mounting handles 117.

[0053] In a preferred embodiment, the pressing assembly 110 further includes a scale (not shown), which can be fixed to two end faces of the support frame 119 opposite to each other along a first direction, with the scale graduations on the scale arranged along a second direction. Exemplarily, the scale can be provided on one end face of the support frame 119, or it can be provided on both end faces. This arrangement, by providing the scale on the end faces of the support frame 119, facilitates the centering of the specimen 200 in the second direction.

[0054] As shown in Figure 5, the dimensions of the first upper clamping plate 111, the second upper clamping plate 112, and the upper pressure plate 113 in the first direction are larger than the width of the specimen 200. This design allows the specimen 200 to be positioned at the midpoint of the first upper clamping plate 111 and the second upper clamping plate 112 in the first direction during testing, as indicated by the dashed arrow in Figure 5. When a clamping load is applied to the first upper clamping plate 111 and the second upper clamping plate 112, space can be provided at the end of the specimen 200 for lateral deformation (as indicated by the solid arrow), allowing for free in-plane deformation due to the Poisson effect. This reduces stress concentration at the interface between the specimen 200 and the clamping plates, preventing premature failure of the specimen 200 and test failure. Preferably, the contact surfaces between the first upper clamping plate 111 and the second upper clamping plate 112 and the upper pressure plate 113 do not have chamfers on the side closest to the specimen 200 (as shown by the dashed line in Figure 2). This design further reduces deformation inconsistencies and stress concentration in the local area of ​​the end clamping interface of the specimen 200.

[0055] As shown in Figure 6, the pressing assembly 120 includes a first lower clamping plate 121, a second lower clamping plate 122, and a pressing plate 123. The first lower clamping plate 121 and the second lower clamping plate 122 are arranged parallel to each other on the front and back sides of the clamp 100, with a gap between them, so that the specimen 200 can be inserted between them and clamped from both sides of the specimen 200. The pressing plate 123 is connected below the first lower clamping plate 121 and the second lower clamping plate 122 and is used to abut against the lower end face of the specimen 200 to transfer the compressive load. Preferably, the contact surfaces between the first lower clamping plate 121 and the second lower clamping plate 122 and the pressing plate 123 have no chamfer on the side near the specimen 200. This design can further reduce the deformation inconsistency and stress concentration of the specimen 200 in the local area of ​​the end clamping interface.

[0056] The compression test fixture 100 also includes a support base 130 disposed at the bottom. The support base 130 includes a base body 131, which is generally rectangular in shape. A lower pressure plate 123 is connected to the upper part of the base body 131 by fasteners. A first lower clamping plate 121 and a second lower clamping plate 122 are connected to the base body 131 above the lower pressure plate 123 by the same fasteners. That is, the first lower clamping plate 121, the second lower clamping plate 122, and the lower pressure plate 123 are connected to the base body 131 by common fasteners.

[0057] In a preferred embodiment, the gap between the first lower clamping plate 121 and the second lower clamping plate 122 in the second direction is adjustable. As shown in FIG6, the first lower clamping plate 121 and the second lower clamping plate 122 are provided with a plurality of third elongated guide holes 124, which extend along the second direction. Fasteners extend through the third elongated guide holes 124 and are fastened to the lower pressure plate 123 and the base body 131. The lower pressure assembly 120 also includes a plurality of second adjusting bolts 125 and a first support plate 126 and a second support plate 127 respectively disposed on the outer sides of the first lower clamping plate 121 and the second lower clamping plate 122. The first support plate 126 and the second support plate 127 are respectively connected to the base body 131 on opposite sides along the second direction. Preferably, the first support plate 126 and the first lower clamping plate 121 are symmetrically arranged with respect to the second support plate 127 and the second lower clamping plate 122 about the center line extending along the first direction of the base body 131. Multiple second adjusting bolts 125 are respectively disposed on the first support plate 126 and the second support plate 127, extending through the first support plate 126 to abut against the first lower clamping plate 121 and through the second support plate 127 to abut against the second lower clamping plate 122. Preferably, the multiple second adjusting bolts 125 are respectively disposed on the upper part of the first support plate 126 and the second support plate 127. The lower parts of the first support plate 126 and the second support plate 127 are respectively fastened to the base body 131 by fasteners. The second adjusting bolts 125 can be used to adjust the position and clamping force of the first lower clamping plate 121 and the second lower clamping plate 122 to accommodate specimens 200 of different thicknesses, thereby enhancing the versatility of the compression test fixture 100.

[0058] Similar to the first upper clamping plate 111, the second upper clamping plate 112, and the upper pressure plate 113, the dimensions of the first lower clamping plate 121, the second lower clamping plate 122, and the lower pressure plate 123 in the first direction are also larger than the width of the specimen 200, thereby allowing the two sides of the specimen 200 to be unconstrained and thus freely deformable in the plane. Preferably, the dimensions of the first lower clamping plate 121, the second lower clamping plate 122, and the lower pressure plate 123 in the first direction can be the same as the dimensions of the first upper clamping plate 111, the second upper clamping plate 112, and the upper pressure plate 113 in the first direction.

[0059] Preferably, the pressing assembly 120 further includes a centering scale line, which, for example, may be disposed on at least one of the first support plate and the second support plate. In actual operation, the centering scale line can be aligned with the center line on the specimen to facilitate centering the specimen in the first direction.

[0060] Main body fixing components

[0061] As shown in Figure 7, the main fixing assembly 140 includes a first cover plate 141 disposed on the front side of the specimen 200, a plurality of first transverse supports 143, and a plurality of first longitudinal supports 144. The plurality of first transverse supports 143 and the plurality of first longitudinal supports 144 are arranged perpendicular to each other. The first cover plate 141 is connected to the plurality of first transverse supports 143 and the plurality of first longitudinal supports 144 on the outside of the plurality of first transverse supports 143 and the plurality of first longitudinal supports 144. The main fixing assembly 140 also includes a second cover plate 142 disposed on the reverse side of the specimen 200, a plurality of second transverse supports and a plurality of second longitudinal supports (not shown). The plurality of second transverse supports and the plurality of second longitudinal supports are arranged perpendicular to each other. The second cover plate 142 is connected to the plurality of second transverse supports and the plurality of second longitudinal supports on the outside of the plurality of second transverse supports and the plurality of second longitudinal supports.

[0062] The first cover plate 141 and the second cover plate 142 are respectively connected to the first transverse support 143 and the second transverse support via the third adjusting bolt 145. The first cover plate 141 and the second cover plate 142 are respectively connected to the first longitudinal support 144 and the second longitudinal support via the fourth adjusting bolt 146. The first cover plate 141 and the second cover plate 142 are each provided with a fourth long guide hole 147 for the third adjusting bolt 145 to pass through. The fourth long guide hole 147 extends along a third direction, which is parallel to the length direction (i.e., the height direction) of the specimen 200. This design facilitates adjustment of the height of the first transverse support 143 and the second transverse support, as well as the position of the first longitudinal support 144 and the second longitudinal support along the third direction. This allows for customizable and adjustable out-of-plane support on the specimen surface, tailored to different specimen sizes, load types, and patch arrangement schemes. This design improves support efficiency and avoids interference with strain gauges, thus meeting various testing requirements. By setting the third adjusting bolt 145 and the fourth adjusting bolt 146, it is also convenient to adjust the clamping force between the longitudinal support and the transverse support and the specimen 200, so that the fixture can adapt to specimens of different thicknesses.

[0063] Referring again to Figure 7, the two ends of the first cover plate 141 are respectively connected to the first support member 151 and the second support member 152 (described below) located on both sides of the main body fixing assembly 140 via fifth adjusting bolts 153. The two ends of the second cover plate 142 are also respectively connected to the first support member 151 and the second support member 152 located on both sides of the main body fixing assembly 140 via fifth adjusting bolts 153. Preferably, the first cover plate 141 and the second cover plate 142 are also respectively provided with fifth long guide holes 164 for the fifth adjusting bolts 153 to pass through. The fifth long guide holes 164 extend along a first direction, and the positions of the first cover plate 141 and the second cover plate 142 can be adjusted along the fifth long guide holes 164, thereby facilitating the installation and position adjustment of the first cover plate 141 and the second cover plate 142.

[0064] Preferably, as shown in FIG7, the main body fixing assembly 140 includes a pair of first cover plates 141 spaced apart along a third direction and a pair of second cover plates 142 spaced apart along a third direction. A first longitudinal support 144 extends between the pair of first cover plates 141, and a second longitudinal support extends between the pair of second cover plates 142. That is, the first longitudinal support 144 extends from the upper first cover plate 141 to the lower first cover plate 141, and the second longitudinal support extends from the upper second cover plate 142 to the lower second cover plate 142.

[0065] Side support components

[0066] The side support assembly 150 is located on two opposite sides of the main fixing assembly 140 along the first direction, and is mainly used to support the specimen 200 from the side. As shown in Figures 7 and 8, the side support assembly 150 includes a first support member 151 and a second support member 152 located on both sides of the main fixing assembly 140. As described above, the two ends of the first cover plate 141 and the two ends of the second cover plate 142 are respectively connected to the first support member 151 and the second support member 152 by the fifth adjusting bolt 153.

[0067] As shown in Figure 8, a portion of the cross-section of the first support member 151 and the second support member 152 has a U-shaped structure. The side support assembly 150 also includes a first blade clamping member disposed inside the U-shaped structure of the first support member 151 and a second blade clamping member disposed inside the U-shaped structure of the second support member 152. The first blade clamping member is connected to the first support member 151 by an adjusting bolt, and the second blade clamping member is connected to the second support member 152 by an adjusting bolt. The first blade clamping member and the second blade clamping member each include a pair of blade clamping portions 154 spaced apart along a second direction. The pair of blade clamping portions 154 are configured to clamp the specimen 200 from both sides. The blade clamping portions 154 are connected to the corresponding first support member 151 and second support member 152 by adjusting bolts, allowing adjustment of the position and clamping force of the blade clamping portions 154 to meet the requirements of specimens of different thicknesses.

[0068] In a preferred embodiment, as shown in FIG1, the specimen 200 has R-angle openings 201 on both sides along its width direction, and correspondingly, the side support assembly 150 does not have a blade clamping part 154 at the position corresponding to the R-angle openings 201.

[0069] Additional support components

[0070] As shown in Figures 1 and 8, the additional support assembly 160 includes a first additional support 161 and a second additional support 162 located outside the first support 151 and the second support 152, respectively. The first additional support 161 and the second additional support 162 are each approximately constructed as a right-angled triangle. One right-angled side of the triangle is connected to the first support 151 or the second support 152 via a fastener, and the other right-angled side is fixedly connected to the support base 130. This design allows the first additional support 161 and the second additional support 162 to provide lateral support stiffness to the first support 151 and the second support 152, respectively, ensuring the stability of the test fixture during testing. Preferably, the first additional support 161 and the second additional support 162 are each provided with multiple weight-reducing openings 163, thereby reducing weight while providing lateral support stiffness, thus facilitating the installation and movement of the test fixture.

[0071] Support base 130

[0072] As shown in Figure 8, the support base 130 includes a first base slider 132 and a second base slider 133, which are fastened to the base body 131. The first base slider 132 and the second base slider 133 are spaced apart along a first direction, and the specimen 200 can be disposed between the first base slider 132 and the second base slider 133. The first base slider 132 is fixedly connected to the first support member 151 and the first additional support member 161 to form a synchronously movable integral part, and the second base slider 133 is fixedly connected to the second support member 152 and the second additional support member 162 to form a synchronously movable integral part. Preferably, the first base slider 132 and the second base slider 133 are configured to slide along the first direction on the base body 131, so that the gap between the first base slider 132 and the second base slider 133 can be adjusted.

[0073] In a preferred embodiment, the first base slider 132 and the second base slider 133 are respectively provided with a plurality of sixth long guide holes 139, which extend along a first direction. Fasteners extend through the sixth long guide holes and are fastened to the base body 131, thereby allowing the first base slider 132 and the second base slider 133 to be displaced along the sixth long guide holes 139, thus adjusting the gap between the first base slider 132 and the second base slider 133 in the first direction. As shown in FIG8, the support base 130 also includes a plurality of sixth adjusting bolts 138, which are respectively connected to two opposite end faces of the base body 131 along the first direction and extend through the side wall of the base body 131 to abut against the first base slider 132 and the second base slider 133. The sixth adjusting bolts 138 can be used to adjust the position of the first base slider 132 and the second base slider 133 to accommodate specimens 200 of different widths, thereby enhancing the versatility of the compression test fixture 100.

[0074] In a preferred embodiment, the support base 130 further includes guide blocks 134 disposed on both sides of each of the first base slider 132 and the second base slider 133. The guide blocks 134 are fixedly connected to the base body 131 by fasteners and the guide blocks 134 on both sides are spaced apart along a second direction. The guide blocks 134 can constrain and limit the movement direction of the first base slider 132 and the second base slider 133 to prevent the first base slider 132 and the second base slider 133 from deviating during movement.

[0075] The assembly steps of the compression test fixture 100 and the specimen 200 will be described below.

[0076] During installation, firstly, fasteners are used to connect the base body 131 of the support base 130 to the testing machine. Next, the first base slider 132 and the second base slider 133 can be connected to the side support assembly 150 and the additional support assembly 160 respectively using fasteners to form a single, slidable assembly. The adjusting bolts of the side support assembly 150 are adjusted to adjust the gap of the knife-edge clamping part 154 to a suitable size for subsequent insertion of the specimen 200. The guide block 134 is fixed to the base body 131 using fasteners to form a guide rail to restrict the movement of the base slider.

[0077] The first support plate 126 and the second support plate 127 are connected to the base body 131 by fasteners. After the lower plate 123 of the lowering assembly 120 is placed in the designated position, the specimen 200 is centered by the centering scale line set on the lowering assembly 120. Then, the second adjusting bolt 125 can be adjusted to make the first lower clamping plate 121 and the second lower clamping plate 122 of the lowering assembly 120 clamp the specimen 200.

[0078] Adjust the sixth adjusting bolt 138 of the support base 130 to move the first base slider 132 and the second base slider 133 on both sides, so that the blade clamping part 154 of the first support member 151 and the second support member 152 on both sides clamps the specimen 200.

[0079] Next, install the main fixing component 140, and adjust the positions of the first transverse support 143 and the second transverse support to avoid interference with the strain gauge.

[0080] Install the upper pressure assembly 110, and adjust the spacing bolts of the upper pressure assembly 110, the main body fixing assembly 140, and the side support assembly 150. At the same time, use the scale of the upper pressure assembly 110 to adjust the specimen 200 so that it is centered in the second direction, thereby completing the installation of the specimen 200 and the test fixture 100.

[0081] It should be understood that this application is not limited to the embodiments shown above. This application is not limited to the number, material, or clamping form of the pressure plate and clamping plate. Any equivalent changes made based on the technical teachings of this application are also within the protection scope of this application.

[0082] The above description of various embodiments of this utility model is provided for descriptive purposes to a person skilled in the art. It is not intended to exclude or limit the utility model to a single disclosed embodiment. As taught above, those skilled in the art will understand that various alternatives and variations of this utility model are possible. Therefore, although some alternative embodiments have been specifically described, those skilled in the art will understand or relatively easily develop other embodiments. This utility model is intended to include all alternatives, modifications, and variations of the utility model described herein, as well as other embodiments falling within the spirit and scope of the utility model described above.

Claims

1. A fixture (100) for compression testing of a composite flat specimen (200), characterized in that, The clamp (100) includes an upper pressure assembly (110), which includes a first upper clamping plate (111), a second upper clamping plate (112), and an upper pressure plate (113). The first upper clamping plate (111) and the second upper clamping plate (112) are arranged parallel to each other on the front and back sides of the clamp (100) and a gap is formed between them, so that the specimen (200) can be inserted between them and the specimen (200) can be lifted out of the clamp (100). The specimen (200) is clamped between the front and back sides of the first upper clamping plate (111) and the second upper clamping plate (112), and the upper pressure plate (113) is connected to the upper part of the first upper clamping plate (111) and the second upper clamping plate (112) and is configured to abut against the upper end face of the specimen (200); and a lower pressure assembly (120) is provided, the lower pressure assembly (120) including a first lower clamping plate (121), a second lower clamping plate (122) and a lower pressure plate (123), the first lower clamping plate (121) The first lower clamp (121) and the second lower clamp (122) are arranged parallel to each other on the front and back sides of the clamp (100) and a gap is formed between them, so that the specimen (200) can be inserted therebetween and clamped from the front and back sides of the specimen (200). The lower pressure plate (123) is connected to the lower part of the first lower clamp (121) and the second lower clamp (122) and is configured to abut against the lower end face of the specimen (200). The dimensions of the first upper clamp (111), the second upper clamp (112) and the upper pressure plate (113) in a first direction parallel to the width direction of the specimen (200) are greater than the width of the specimen (200), and the dimensions of the first lower clamp (121), the second lower clamp (122) and the lower pressure plate (123) in the first direction are greater than the width of the specimen (200).

2. The clamp (100) according to claim 1, characterized in that, The upper pressure assembly (110) also includes a support frame (119) having an inverted U-shaped cross-sectional shape and forming an accommodating space inside. The first upper clamping plate (111) and the second upper clamping plate (112) are connected to the support frame (119) on both sides of the accommodating space by fasteners, and the upper pressure plate (113) is connected to the support frame (119) at the top of the accommodating space by fasteners.

3. The clamp (100) according to claim 2, characterized in that, The first upper clamp (111) and the second upper clamp (112) are configured to adjust the distance between them.

4. The clamp (100) according to claim 3, characterized in that, The top of the support frame (119) has a first elongated guide hole (114) extending in a second direction parallel to the thickness direction of the specimen (200). The upper pressure plate (113) has a second elongated guide hole (115) extending parallel to the first elongated guide hole (114) at a position corresponding to the first elongated guide hole (114). The support frame, the upper pressure plate, and the first upper clamping plate (111) are connected together by fasteners extending through the first elongated guide hole (114) and the second elongated guide hole (115), respectively. The support frame, the upper pressure plate, and the second upper clamping plate (112) are connected together by fasteners that extend through the first long guide hole (114) and the second long guide hole (115), respectively. The upper pressure assembly (110) also includes a plurality of first adjusting bolts (116), which are respectively disposed on two sides of the support frame (119), and extend through the support frame (119) into the receiving space and abut against the first upper clamping plate (111) and the second upper clamping plate (112).

5. The clamp (100) according to claim 2, characterized in that, The pressing assembly (110) further includes mounting handles (117), which are respectively disposed on two sides of the support frame (119) opposite to a second direction parallel to the thickness direction of the specimen (200); and / or the pressing assembly (110) further includes a scale, which is fixed on at least one of the two end faces of the support frame opposite to the first direction.

6. The clamp (100) according to claim 1, characterized in that, The clamp (100) further includes a support base (130), the support base (130) includes a base body (131), the lower pressure plate (123) is connected to the base body (131) above the base body by fasteners, and the first lower clamping plate (121) and the second lower clamping plate (122) are connected to the base body (131) above the lower pressure plate (123) by fasteners.

7. The clamp (100) according to claim 6, characterized in that, The first lower clamping plate (121) and the second lower clamping plate (122) are configured to adjust the distance between them.

8. The clamp (100) according to claim 7, characterized in that, The first lower clamping plate (121) and the second lower clamping plate (122) are formed with a third long guide hole (124) extending in a second direction parallel to the thickness direction of the specimen (200). The pressing assembly (120) further includes a plurality of second adjusting bolts (125) and a first support plate (126) and a second support plate (127) respectively disposed on the outer side of the first lower clamping plate (121) and the second lower clamping plate (122). The plurality of second adjusting bolts (125) are respectively disposed on the upper end of the first support plate (126) and the second support plate (127), and extend through the first support plate (126) and the second support plate (127) to abut against the first lower clamping plate (121) and the second lower clamping plate (122). The lower ends of the first support plate (126) and the second support plate (127) are fastened to the base body (131).

9. The clamp (100) according to claim 6, characterized in that, The clamp (100) further includes a main body fixing assembly (140), which includes a first cover plate (141) and a second cover plate (142) respectively disposed on the front and back sides of the specimen (200), a plurality of first transverse supports (143) and a plurality of second transverse supports, a plurality of first longitudinal supports (144) and a plurality of second longitudinal supports. The plurality of first transverse supports (143) and the plurality of first longitudinal supports (144) are arranged perpendicular to each other, and the plurality of second transverse supports and the plurality of second longitudinal supports are arranged perpendicular to each other. The first cover plate (141) is connected to the plurality of first transverse supports (143) and the plurality of first longitudinal supports (144) on the outside of the plurality of first transverse supports (143) and the plurality of first longitudinal supports (144). The second cover plate (142) is connected to the plurality of second transverse supports and the plurality of second longitudinal supports on the outside of the plurality of second transverse supports and the plurality of second longitudinal supports.

10. The clamp (100) according to claim 9, characterized in that, The first cover plate (141) and the second cover plate (142) are respectively connected to the first transverse support (143) and the second transverse support by the third adjusting bolt (145). The first cover plate (141) and the second cover plate (142) are respectively connected to the first longitudinal support (144) and the second longitudinal support by the fourth adjusting bolt (146). The first cover plate (141) and the second cover plate (142) are respectively provided with a fourth long guide hole (147) for the third adjusting bolt (145) to pass through. The fourth long guide hole (147) extends in a third direction parallel to the length direction of the specimen (200).

11. The clamp (100) according to claim 9, characterized in that, The clamp also includes a side support assembly (150), which includes a first support member (151) and a second support member (152). The first support member (151) and the second support member (152) are located on opposite sides of the main body fixing assembly (140) along the first direction. The two ends of the first cover plate (141) and the two ends of the second cover plate (142) are respectively connected to the first support member (151) and the second support member (152) by a fifth adjusting bolt (153). The first cover plate (141) and the second cover plate (142) are also respectively provided with a fifth long guide hole (164) extending along the first direction for the fifth adjusting bolt (153) to pass through.

12. The clamp (100) according to claim 10, characterized in that, The main body fixing assembly (140) includes a pair of first cover plates (141) spaced apart along the third direction and a pair of second cover plates (142) spaced apart along the third direction.

13. The clamp (100) according to claim 11, characterized in that, A portion of the first support member (151) and the second support member (152) have a U-shaped cross-sectional shape. The side support assembly (150) further includes a first blade clamping member and a second blade clamping member disposed inside the U-shaped structure of each of the first support member (151) and the second support member (152). The first blade clamping member is connected to the first support member (151) by an adjusting bolt, and the second blade clamping member is connected to the second support member (152) by an adjusting bolt. The first blade clamping member and the second blade clamping member each include a pair of blade clamping portions (154). The pair of blade clamping portions (154) are configured to clamp the specimen (200) from both sides. The specimen (200) has R-angle openings on both sides opposite to each other along the first direction. The side support assembly (150) does not have the blade clamping portions (154) at the position corresponding to the R-angle openings.

14. The clamp (100) according to claim 11, characterized in that, The clamp also includes an additional support assembly (160), which includes a first additional support (161) and a second additional support (162) located on the outside of the first support (151) and the second support (152), respectively. The first additional support (161) and the second additional support (162) are connected to the first support (151) and the second support (152) respectively by fasteners, and the first additional support (161) and the second additional support (162) are both connected to the support base (130). The first additional support (161) and the second additional support (162) are respectively constructed as triangular structures, and the first additional support (161) and the second additional support (162) are respectively provided with weight reduction openings (163).

15. The clamp (100) according to claim 14, characterized in that, The support base (130) further includes a first base slider (132) and a second base slider (133) disposed on the base body (131). The first base slider (132) and the second base slider (133) are spaced apart along the first direction. The test piece (200) can be disposed between the first base slider (132) and the second base slider (133). The first base slider (132) is fixedly connected to the first support member (151) and the first additional support member (161). The second base slider (133) is fixedly connected to the second support member (152) and the second additional support member (162). The first base slider (132) and the second base slider (133) are configured to slide along the first direction on the base body (131), so that the gap between the first base slider (132) and the second base slider (133) can be adjusted.

16. The clamp (100) according to claim 15, characterized in that, The support base (130) further includes guide blocks (134) disposed on both sides of each of the first base slider (132) and the second base slider (133). The guide blocks (134) on both sides are spaced apart along the thickness direction of the specimen (200), and the guide blocks (134) are fixedly connected to the base body (131).

17. The clamp (100) according to claim 15, characterized in that, The contact surfaces between the first upper clamping plate (111) and the second upper clamping plate (112) and the upper pressure plate (113) have no chamfer on the side near the specimen, and / or the contact surfaces between the first lower clamping plate (121) and the second lower clamping plate (122) and the lower pressure plate (123) have no chamfer on the side near the specimen.

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