Adjustable tensile testing apparatus and testing machine for L-shaped specimens

Abstract

This utility model discloses an adjustable tensile testing device for an L-shaped specimen, characterized in that the adjustable tensile testing device comprises: a base plate, the base plate including a guide rail arranged on the upper surface of the base plate along the longitudinal extension direction of the base plate; a pair of side plates, each of the pair of side plates being arranged perpendicular to the upper surface of the base plate and configured to engage the guide rail, thereby allowing each side plate to slide along the guide rail; a loading plate, the loading plate being mounted between the pair of side plates and configured to be connected to the short side segment of the L-shaped specimen via a connecting member; and a sliding locking assembly, the sliding locking assembly being capable of locking the sliding of the side plate relative to the base plate.

Description

Technical Field

[0001] This utility model relates to a strength testing device for composite material components, specifically to an adjustable tensile testing device and testing machine for L-shaped specimens. Background Technology

[0002] In the aerospace field, carbon fiber reinforced resin matrix composites possess excellent properties such as high designability, high specific strength and specific modulus, ease of integral molding, corrosion resistance, and lightweight. Therefore, composite material components are widely used in various aerospace structures. Since composite material components are subjected to complex stress states over long periods, it is necessary to conduct mechanical testing studies on them.

[0003] Typically, aircraft wing spars adopt a C-shaped structure. The orientation of the wing spars and the shape of the wing surface will affect the angle between the wing spar and the web, making it appear as an open (angle ≥ 90°) or closed (angle < 90°) feature. Moreover, the angle will change with the curvature of the wing surface.

[0004] For C-shaped wing beam structures, the out-of-plane load-bearing capacity of the R-zone is relatively weak. Due to eccentricity, the tensile load on the web generates a large concentrated moment in the R-zone, resulting in significant interlaminar stress. This tensile load is the primary source of the out-of-plane load borne by the R-zone; therefore, interlaminar tensile failure is the main failure mode for beam ribs and other structures containing the R-zone. Furthermore, since the R-zone is pre-formed from flat sheet thermal insulation film, it is prone to fiber wrinkling, resin buildup, and thinning, all of which affect its load-bearing capacity. To obtain the loading state of the R-zone in an actual structure and the expected interlaminar failure mode and failure load, tensile tests on the R-zone are necessary.

[0005] Currently, commonly used R-zone tensile specimens are L-shaped. Typically, the angle between the flange and web of an R-zone tensile specimen is a right angle. However, in reality, the angle between the flange and web of an aircraft wing spars varies with the curvature of the wing surface, generally ranging from 85° to 95°. Therefore, simplifying the R-zone specimen to a right angle for testing deviates somewhat from the actual structure. Furthermore, the thickness of an aircraft wing spars varies continuously from the root to the tip, and the fasteners used to connect the flange and web have various grades and arrangements. Therefore, R-zone tensile tests require multiple specimens with different thicknesses, angles, widths, and fastener arrangements. Consequently, multiple fixtures of different sizes are needed for R-zone tensile specimens with different dimensions and fasteners.

[0006] To realistically simulate tensile failure in the R-zone of a spar, a testing apparatus suitable for tensile specimens in the R-zone with different angles and sizes is needed to ensure high loading accuracy, reusability, and test success rate. Utility Model Content

[0007] To simulate the loading state, failure mode, and delamination failure of the R-zone caused by tensile load in actual structures, this invention proposes an adjustable tensile testing device for L-shaped specimens, comprising: a base plate including a guide rail arranged on the upper surface of the base plate along its longitudinal extension direction; a pair of side plates, each of which is arranged perpendicular to the upper surface of the base plate and configured to engage the guide rail, thereby allowing each side plate to slide along the guide rail; a loading plate disposed between the pair of side plates and configured to be connected to the short side segment of the L-shaped specimen via a connector; and a sliding locking assembly capable of locking the sliding of the side plates relative to the base plate.

[0008] According to one embodiment of the present invention, the sliding locking assembly includes a limiting block configured to slide on the guide rail and a stop configured to connect the limiting block and lock the movement of the limiting block, wherein the limiting block contacts the side plate and is disposed on the side of the side plate away from the loading plate.

[0009] According to one embodiment of the present invention, the bottom of the limiting block has a notch with a cross-sectional shape consistent with that of the guide rail to engage with the guide rail, thereby allowing the limiting block to slide along the guide rail. The limiting block also includes a through hole formed at the bottom corner of the limiting block to communicate with the notch. The stop member is accommodated in the through hole and abuts against the guide rail to lock the sliding of the limiting block.

[0010] According to one embodiment of the present invention, the bottom of the side plate is provided with a notch whose cross-sectional shape is consistent with that of the guide rail to engage the guide rail.

[0011] According to one embodiment of the present invention, the guide rail includes a pair of guide rails extending parallel to each other, the notch includes two notches located on the bottom sides of the side plate respectively, the side plate also includes a through hole formed at the bottom corner of the side plate to communicate with the notch, and the sliding locking assembly includes a locking member that can be accommodated in the through hole of the side plate and abut against the guide rail to lock the sliding of the side plate.

[0012] According to one embodiment of the present invention, the loading plate is configured to be pivotally connected to the pair of side plates, thereby enabling the loading plate to pivot between the pair of side plates. The adjustable tensile testing device further includes a rotation locking assembly configured to lock the rotation of the loading plate between the pair of side plates, thereby keeping the long side of the L-shaped specimen in a vertical state.

[0013] According to one embodiment of the present invention, the loading plate includes a first through hole disposed on a first longitudinal side of the loading plate and extending along the longitudinal direction of the loading plate, the first through hole being configured to receive a pivot for pivotally connecting the loading plate between the pair of side plates.

[0014] According to one embodiment of the present invention, the pivot is connected to a first side of the side plate, the side plate includes an arcuate slot penetrating the side plate on a second side opposite to the first side, and the loading plate further includes a second through hole formed on a second longitudinal side opposite to the first longitudinal side, the second through hole extending parallel to the first through hole, wherein the rotation locking assembly includes: a rod capable of passing sequentially through the arcuate slot of the side plate and the second through hole of the loading plate, and the end of the rod being capable of rotating about the pivot within the arcuate slot; and a limiter, one end of the limiter being connected to the side plate and the other end being connected to the end of the rod, and the limiter being configured to adjust the rotation angle of the rod, thereby limiting the rotation of the loading plate.

[0015] According to one embodiment of the present invention, the pivot has an end that can extend through the side plate, and the rotation locking assembly further includes a fastener connected to the end of the pivot to restrict the rotation of the loading plate.

[0016] According to one embodiment of the present invention, the guide rail has distance scale lines formed on its surface.

[0017] According to one embodiment of the present invention, the arc-shaped slot has angle scale lines formed at its arc-shaped edge.

[0018] According to one embodiment of the present invention, the loading plate further includes a plurality of connecting through holes formed on the loading plate, and the connecting member passes through the plurality of connecting through holes to fix the short side of the L-shaped specimen to the loading plate.

[0019] According to one embodiment of the present invention, the loading plate has an opening penetrating the loading plate in the middle of the first longitudinal side, wherein the adjustable tensile testing device further includes a support member, one end of the support member is disposed in the opening and has a support through hole aligned with the first through hole to accommodate the pivot, and the other end of the support member is configured to engage the guide rail, so that the support member can slide along the guide rail.

[0020] According to one embodiment of the present invention, the other end of the support member has a notch at its bottom with a cross-sectional shape consistent with that of the guide rail to engage the guide rail.

[0021] According to one embodiment of the present invention, the support member includes a through hole formed at the bottom corner of the support member and communicating with the recess of the support member, and a locking member is accommodated in the through hole and abuts against the guide rail to lock the sliding of the support member.

[0022] According to one embodiment of the present invention, the loading plate includes multiple loading plates of various sizes, and / or the multiple connecting through holes have different arrangement patterns.

[0023] According to this utility model, a testing machine is also proposed, which includes the adjustable tensile testing device as described above.

[0024] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of this utility model.

[0025] The positive and progressive effects of the above-described embodiments of this utility model are as follows:

[0026] 1) The side plate spacing and loading plate angle of the adjustable tensile testing device can be adjusted according to the specific specifications of the L-shaped specimen. Therefore, the adjustable tensile testing device is suitable for various L-shaped specimens of different sizes and angles.

[0027] 2) The adjustable tensile testing device has a detachable structure and the loading plate is easy to replace. Therefore, different sizes and / or different arrangements of connecting through holes can be selected according to different specimens to accurately simulate the stress state, failure mode and interlaminar delamination failure in the R zone of the actual structure, and can reduce costs and improve test efficiency. Attached Figure Description

[0028] Figure 1 A perspective view of a test fixture including an adjustable tensile testing apparatus according to a first embodiment of the present invention;

[0029] Figure 2 An exploded view of the test fixture including the adjustable tensile testing apparatus according to the first embodiment of the present invention;

[0030] Figure 3 This is an exploded view of the adjustable tensile testing device according to the first embodiment of the present invention;

[0031] Figure 4 A perspective view of a test fixture including an adjustable tensile testing apparatus according to a second embodiment of the present invention;

[0032] Figure 5 This is an exploded view of the sliding locking assembly of the adjustable tensile testing device according to the second embodiment of the present invention. Detailed Implementation

[0033] The preferred embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The following description is exemplary and not intended to limit the present invention. Any other similar situations also fall within the protection scope of the present invention.

[0034] In the following detailed description, directional terms such as "left," "right," "up," "down," "front," and "back" are used with reference to the directions described in the accompanying drawings. Components of embodiments of this invention can be positioned in a variety of different orientations; the directional terms are for illustrative purposes and not limiting.

[0035] This utility model proposes an adjustable tensile testing device for L-shaped specimens, which can connect various L-shaped specimens 300 to a tensile testing machine for tensile testing. For example... Figure 1 As shown in the figure, this is a test fixture including an adjustable tensile testing device 100 according to a first embodiment of the present invention. According to the first embodiment, the long side of an L-shaped specimen 300 is connected to a loading head 400 of a tensile testing machine (not shown), and the short side of the L-shaped specimen is connected to the adjustable tensile testing device 100 via a connector 302. The adjustable tensile testing device 100 is fixed to the tensile testing machine, thereby connecting the L-shaped specimen 300 to the tensile testing machine. During operation of the tensile testing machine, the loading head 400 applies a tensile force to the L-shaped specimen 300 to perform a tensile test.

[0036] Figure 2 This is an exploded view of the test fixture including the adjustable tensile testing apparatus according to the first embodiment of the present invention. As shown, the loading head 400 clamps the long side of the L-shaped specimen 300 via the clamp 401 to apply tensile force to the L-shaped specimen 300. The short side of the L-shaped specimen 300 is connected to the adjustable tensile testing apparatus 100 via a connector 302 passing through the through hole 301. The connector 302 can be any connector used to connect the flange and the skin, such as a bolt, rivet, etc.

[0037] Figure 3This is an exploded view of an adjustable tensile testing apparatus according to a first embodiment of the present invention. As shown, the adjustable tensile testing apparatus 100 includes a base plate 101, a pair of side plates 103, a loading plate 109, and a sliding locking assembly. The base plate 101 is fixed to a tensile testing machine and includes a pair of guide rails 102 arranged on the upper surface of the base plate along its longitudinal extension direction. The side plates 103 are arranged perpendicular to the upper surface of the base plate and perpendicular to the guide rails 102, and are configured to engage the guide rails 102, thereby allowing the side plates 103 to slide along the guide rails 102 on the base plate 101. The loading plate 109 is mounted between the pair of side plates 103 and is configured to be connected to the short side of an L-shaped specimen 300 via a connecting member 302. The sliding locking assembly includes a plurality of locking members 108 capable of locking the sliding of the side plates 103 relative to the base plate 101.

[0038] Preferably, the bottom sides of the side plate 103 each include recesses 106 penetrating the side plate. The spacing between these recesses 106 is equal to the spacing between the guide rails 102, and the recesses 106 are configured such that their cross-sectional shape matches that of the guide rails to engage with them, allowing the side plate 103 to slide along the guide rails 102 on the base plate 101. The side plate 103 transmits the tensile force applied by the tensioning machine through the engagement of the recesses 106 and the guide rails 102. Therefore, the cross-sectional shape of the recesses 106 can include any shape that can slide with the guide rails 102 and transmit tensile force, such as dovetail, T-shaped, L-shaped, etc.

[0039] A locking through hole 107 is provided at the bottom corner of the side plate 103 where a recess 106 is provided. The locking through hole 107 extends into and connects to the recess 106. A locking member 108 is accommodated in the locking through hole 107 and abuts against the guide rail 102, thereby fixing the relative position of the side plate 103 and the bottom plate 101 by compression and friction. Preferably, the locking through hole 107 is a threaded hole, and the locking member 108 is a bolt.

[0040] Preferably, a distance scale line is engraved on the surface of the guide rail 102, thereby allowing the distance value between the side plates to be known, and the side plate spacing of the adjustable tensile testing device 100 to be pre-adjusted according to the width of the L-shaped specimen 300.

[0041] By configuring the side plates 103 to slide on the base plate guide rail 102 and adjusting the side plate spacing via the locking member 108, the adjustable tensile testing apparatus 100 can be used for L-shaped specimens 300 with different widths, thereby achieving a width adjustment function. Therefore, without replacing the entire tensile testing fixture, the adjustable tensile testing apparatus 100 can accommodate L-shaped specimens 300 of various sizes, improving testing efficiency.

[0042] Preferably, the loading plate 109 is pivotally connected between a pair of side plates 103. Specifically, as Figure 3 As shown, the loading plate 109 includes a first through hole 110 disposed on its first longitudinal side and extending along the longitudinal direction of the loading plate 109. The first through hole 110 is configured to receive a pivot 114 for pivotally connecting the loading plate 109 between a pair of side plates 103. The side plates 103 include side plate through holes 105 on their first sides, which are aligned with the first through hole 110 of the loading plate 109 such that the end of the pivot 114 passes through, thereby pivotally connecting the loading plate 109 between the pair of side plates 103. When the short side of the L-shaped specimen 300 is connected to the loading plate 109, by rotating the loading plate 109 about the pivot 114, the angle between the short side of the L-shaped specimen 300 and the horizontal plane can be adjusted so that the long side of the L-shaped specimen 300 is in a vertical plane and aligned with the tensile loading path of the tensile testing machine.

[0043] like Figure 3 As shown, the adjustable tensile testing apparatus 100 also includes a rotation locking assembly for locking the rotation of the loading plate 109. Specifically, the side plate 103 includes an arcuate slot 104 centered on the side plate through hole 105 on its second side opposite to the first side, and the loading plate 109 includes a second through hole 111 on its second longitudinal side opposite to the first longitudinal side. The second through hole 111 is configured to extend parallel to the first through hole 110 along the longitudinal direction of the loading plate 109. The rotation locking assembly includes a rod 117 and a limiter 118. The rod 117 is configured to pass sequentially through the arcuate slot 104 of the side plate 103 and the second through hole 111 of the loading plate 109, such that the end of the rod 117 can rotate about a pivot 114 within the arcuate slot 104. The limiter 118 is any rotation limiter available on the market. One end of the limiter 118 is connected to the side plate 103, and the other end is connected to the end of the rod 117. Thus, the limiter 118 can adjust the rotation angle of the rod 117, thereby limiting the rotation of the loading plate 109.

[0044] Preferably, rod 117 is a screw, and the other end of limiter 118 is connected to the threaded end of the screw.

[0045] Preferably, the end of the pivot 114 extends through a side plate through-hole 105. Fasteners of the rotation locking assembly are connected to the end of the pivot 114 so that the side plate 103 presses against the loading plate 109, thereby further locking the rotation of the loading plate 109. Specifically, the end of the pivot 114 is configured to have threads. Fasteners such as nuts 115 and washers 116 are threadedly connected to the end of the pivot 114 and press against the side plate 103 to achieve further rotation locking.

[0046] Preferably, an angle scale line is formed at the arc-shaped edge of the arc-shaped slot 104, thereby revealing the rotation angle of the loading plate 109 and the included angle of the L-shaped specimen. A zero-degree line can be set in the middle of the arc-shaped edge. The angle value increases as the specimen travels along the arc-shaped edge from this zero-degree line towards the top of the side plate, and decreases as it travels along the arc-shaped edge from this zero-degree line towards the bottom of the side plate. For example, the numerical range of the angle scale line can be -10 degrees to +10 degrees. When the long side of the L-shaped specimen remains vertical, the sum of the included angle of the L-shaped specimen and the rotation angle of the loading plate 109 equals 90 degrees. For example, when the long side of the L-shaped specimen remains vertical and the angle scale line indicates that the loading plate 109 has rotated to 5 degrees, the included angle of the L-shaped specimen is 85 degrees; when the long side of the L-shaped specimen remains vertical and the angle scale line indicates that the loading plate 109 has rotated to -5 degrees, the included angle of the L-shaped specimen is 95 degrees.

[0047] By configuring the loading plate 109 to rotate relative to the side plate 103 and adjusting the rotation angle of the loading plate 109 via a rotation locking assembly, the adjustable tensile testing device 100 of this invention can always keep the long side of an L-shaped specimen 300 with various included angles vertical, so that the loading path of the tensile testing machine can pass through the long side of the L-shaped specimen 300. The adjustable tensile testing device 100 of this invention is applicable to L-shaped specimens 300 with all included angles, thus reducing testing costs and improving testing efficiency.

[0048] Preferably, the loading plate 109 includes a plurality of connecting through holes 112 formed on the loading plate 109, and the connector 302 passes through the plurality of connecting through holes 112 to connect the short side of the L-shaped specimen 300 to the loading plate 109.

[0049] Preferably, the loading plate 109 can have various sizes to accommodate different L-shaped specimens 300.

[0050] Preferably, the multiple connecting through holes 112 of the loading plate 109 can have various arrangement patterns to adapt to different L-shaped specimens 300.

[0051] Preferably, the loading plate 109 has an opening 113 through the middle of its first longitudinal side, one end of the support member 119 is disposed in the opening 113 and has a support through hole 120 aligned with the first through hole 110 to accommodate the pivot 114, and the other end of the support member 119 engages with the guide rail 102 and is able to slide along the guide rail 102.

[0052] Specifically, the bottom of the other end of the support 119 includes a notch 106 that matches the cross-sectional shape of the guide rail 102 in order to engage the guide rail 102.

[0053] Preferably, the bottom corner of the other end of the support member 119 includes a locking through hole 107 extending into and communicating with the recess 106 of the support member. The locking member 108 is accommodated in the locking through hole 107 and abuts against the guide rail 102, locking the sliding of the support member 119 by compression and friction.

[0054] The support member 119 can support the loading plate 109 and the L-shaped specimen 300, providing additional sliding locking function and force transmission path.

[0055] Figure 4 This is a perspective view of a test fixture including an adjustable tensile testing apparatus according to a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the adjustable tensile testing apparatus 200 includes a dedicated sliding locking assembly. This sliding locking assembly is used to lock the sliding of the side plate 103 along the guide rail 102.

[0056] In the second embodiment, the sliding locking assembly includes any structure capable of locking the sliding of the side plate 103, such as, but not limited to, mechanical locking structures, spring-loaded snap-fit ​​structures, electromagnetic locking structures, and hydraulic-pneumatic locking structures. For example, the electromagnetic sliding locking assembly can consist of an electromagnetic chuck and a controller, with the electromagnetic chuck mounted on the slider or guide rail. When locking is required, the controller energizes the electromagnetic chuck, causing it to generate a strong magnetic force that tightly attracts the slider to the guide rail, achieving locking; when the power is off, the magnetic force disappears, and the slider can slide freely.

[0057] Preferably, the sliding locking assembly includes a limiting block 201 configured to slide on the guide rail 102 and a stop configured to engage the limiting block 201 and lock its movement. The limiting block 201 contacts the side plate 103 and is disposed on the side of the side plate 103 away from the loading plate 109. The stop acts on the limiting block 201 by means of, for example, mechanical force, electromagnetic force, hydraulic pressure, etc., to lock the sliding of the limiting block 201.

[0058] like Figure 4 and Figure 5As shown, according to the second embodiment of this utility model, the sliding locking assembly adopts a mechanical locking structure and includes a limiting block 201 and a locking member 108 as a stop. A guide rail 102 is arranged in the middle of the base plate 101. The bottom of the limiting block 201 has a notch 106 with a cross-sectional shape consistent with the cross-sectional shape of the guide rail 102 to engage with the guide rail 102, thereby allowing the limiting block 201 to slide along the guide rail 102. The cross-sectional shape of the notch 106 includes, but is not limited to, dovetail, T-shaped, L-shaped, etc. The bottom corner of the limiting block 201 also includes a locking through hole 107 extending into and communicating with the notch 106. The locking member 108 is accommodated in the locking through hole 107 and abuts against the guide rail 102 to lock the sliding of the limiting block 201 by squeezing and rubbing the guide rail 102. As an example, the locking through hole 107 of the limit block 201 is a threaded hole, and the locking element 108 is a bolt. The bolt is screwed into the threaded hole and presses against the guide rail 102, thereby locking the sliding of the limit block 201.

[0059] In the adjustable tensile testing device 200 of the second embodiment of the present invention, the number of base plate guide rails 102 is not limited to one. For example, the base plate 101 may also include two or more guide rails 102. Accordingly, each guide rail 102 is provided with a sliding locking component.

[0060] The limiting block 201 is slidably engaged with the guide rail 102 through the notch 106, and the limiting block 201 is reliably fixed relative to the base plate 101 by the squeezing and friction of the locking member 108, thereby adjusting the side plate spacing. This sliding locking assembly has a simple structure, is easy to operate, has low cost, and can extend the life of the adjustable tensile testing device 200.

[0061] This utility model also includes a testing machine, which includes the adjustable tensile testing device as described above.

[0062] As an example, the specific operating steps of this testing machine are as follows:

[0063] Step 1: Connect the short side of the L-shaped specimen to the loading plate using bolts;

[0064] Step 2: Adjust the rotation angle of the loading plate so that the long side of the L-shaped specimen passes through the loading axis, that is, ensure that the long side of the L-shaped specimen is vertical.

[0065] Step 3: Adjust the position of the side plate so that it contacts the loading plate, tighten the locking piece to fix the position of the side plate, and then tighten the nut to fix the limiter and fix the posture of the loading plate.

[0066] Step 4: Clamp the long side of the L-shaped specimen using a fixture;

[0067] Step 5: Apply static load, calibrate the tensile testing machine, and adjust the specimen condition;

[0068] Step 6: Apply static load until the L-shaped specimen fails, and record the failure load and displacement of the loading point;

[0069] Step 7: Apply tensile fatigue load and conduct a residual strength test on the L-shaped specimen that has not yet failed.

[0070] This utility model's adjustable tensile testing device can be used for L-shaped specimens of various sizes and angles by adjusting the spacing between the side plates and the rotation angle of the loading plate. Furthermore, the device is easy to disassemble, and the loading plate is available in various specifications, allowing different loading plates to be selected according to different L-shaped specimens. This accurately simulates the actual stress state of the beam's R-zone, improving the accuracy and success rate of the test while reducing the test cost.

[0071] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. An adjustable tensile testing device for L-shaped test pieces, characterized in that, The adjustable tensile testing device includes: A base plate, the base plate including a guide rail arranged on the upper surface of the base plate along the longitudinal extension direction of the base plate; A pair of side plates, each of which is arranged perpendicular to the upper surface of the base plate and configured to engage the guide rail, thereby allowing each side plate to slide along the guide rail; and A loading plate, disposed between the pair of side plates and configured to be connected to the short side segment of the L-shaped specimen via a connector; and A sliding locking assembly capable of locking the sliding of the side plate relative to the base plate.

2. The adjustable tensile testing device of claim 1, wherein, The sliding locking assembly includes a limiting block configured to slide on the guide rail and a stop configured to engage the limiting block and lock its movement, the limiting block contacting the side plate and being disposed on the side of the side plate away from the loading plate.

3. The adjustable tensile testing device of claim 2, wherein, The bottom of the limiting block has a notch with a cross-sectional shape that matches the cross-sectional shape of the guide rail to engage with the guide rail, thereby allowing the limiting block to slide along the guide rail. The limiting block also includes a through hole at the bottom corner of the limiting block that communicates with the notch. The stop member is accommodated in the through hole and abuts against the guide rail to lock the sliding of the limiting block.

4. The adjustable tensile testing device of claim 1, wherein, The bottom of the side plate has a notch with a cross-sectional shape that matches the cross-sectional shape of the guide rail to engage the guide rail.

5. The adjustable tensile testing device of claim 4, wherein, The guide rails include a pair of guide rails extending parallel to each other, the notches include two notches located on the bottom sides of the side plate respectively, the side plate also includes a through hole formed at the bottom corner of the side plate to communicate with the notches, and the sliding locking assembly includes a locking member that can be accommodated in the through hole of the side plate and abut against the guide rails to lock the sliding of the side plate.

6. The adjustable tensile testing device of any one of claims 1-5, wherein, The loading plate is configured to be pivotally connected to the pair of side plates, thereby allowing the loading plate to pivot between the pair of side plates. The adjustable tensile testing device further includes a rotation locking assembly, which is configured to lock the rotation of the loading plate between the pair of side plates, thereby keeping the long side of the L-shaped specimen in a vertical state.

7. The adjustable tensile testing device of claim 6, wherein, The loading plate includes a first through hole disposed on a first longitudinal side of the loading plate and extending along the longitudinal direction of the loading plate, the first through hole being configured to receive a pivot for pivotally connecting the loading plate between the pair of side plates.

8. The adjustable tensile testing device of claim 7, wherein, The pivot is connected to a first side of the side plate, the side plate including an arcuate slot through the side plate on a second side opposite to the first side, and the loading plate further including a second through hole formed on a second longitudinal side opposite to the first longitudinal side, the second through hole extending parallel to the first through hole. The rotation locking assembly includes: A rod, the rod being capable of sequentially passing through an arcuate slot in the side plate and a second through hole in the loading plate, and the end of the rod being capable of rotating about the pivot within the arcuate slot; and A limiter is provided, one end of which is connected to the side plate and the other end of which is connected to the end of the rod. The limiter is configured to adjust the rotation angle of the rod, thereby limiting the rotation of the loading plate.

9. The adjustable tensile testing device of claim 7, wherein, The pivot has an end that extends through the side plate, and the rotation locking assembly further includes a fastener that is coupled to the end of the pivot to restrict rotation of the loading plate.

10. The adjustable tensile testing device of claim 1, wherein, The guide rail has distance scale lines formed on its surface.

11. The adjustable tensile testing device of claim 8, wherein, The arc-shaped slot has angle scale lines formed at its arc-shaped edge.

12. The adjustable tensile testing apparatus according to claim 1, characterized in that, The loading plate also includes a plurality of connecting through holes formed on the loading plate, and the connecting member passes through the plurality of connecting through holes to fix the short side of the L-shaped specimen to the loading plate.

13. The adjustable tensile testing apparatus according to claim 7, characterized in that, The loading plate has an opening penetrating through the middle of the first longitudinal side. The adjustable tensile testing device further includes a support member, one end of which is disposed in the opening and has a support through hole aligned with the first through hole to accommodate the pivot. The other end of the support member is configured to engage the guide rail, allowing the support member to slide along the guide rail.

14. The adjustable tensile testing apparatus according to claim 13, characterized in that, The other end of the support member has a notch at its bottom with a cross-sectional shape that matches the cross-sectional shape of the guide rail to engage the guide rail.

15. The adjustable tensile testing apparatus according to claim 14, characterized in that, The support member includes a through hole formed at the bottom corner of the support member and communicating with the recess of the support member. A locking member is accommodated in the through hole and abuts against the guide rail to lock the sliding of the support member.

16. The adjustable tensile testing apparatus according to any one of claims 1-5 and 7-15, characterized in that, The loading plate includes multiple loading plates of various sizes.

17. The adjustable tensile testing apparatus according to claim 12, characterized in that, The multiple connecting through holes have different arrangement patterns.

18. A testing machine, characterized in that, The testing machine includes an adjustable tensile testing apparatus according to any one of the preceding claims.

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