Stretch testing fixture and pultruded pole stitched composite material structure stretch testing system

Abstract

The utility model discloses tensile test fixture and pultrusion rod suture composite material structure tensile test system, apply to test auxiliary tool technical field, and tensile test fixture includes first clamp and second clamp, and first clamp includes the clamping block subassembly and first connecting piece who are connected, and clamping block subassembly is equipped with the clamping groove of extending along the first direction, and clamping groove includes clamping groove section and connecting groove section, and connecting groove section intercommunication side wall of clamping groove section and the outer end surface of clamping block subassembly, and the width of clamping groove section is greater than the width of connecting groove section, and second clamp includes the base, the limiting block subassembly and second connecting piece who are connected, and limiting block subassembly and base enclose two limiting grooves of extending along the first direction, and the slot mouth interval of two limiting grooves is opposite. The utility model through the cooperation and the connection of each component, can simply, practical for the tensile property test of pultrusion rod suture composite material structure provide equipment support.

Description

Technical Field

[0001] This utility model relates to the field of testing auxiliary tools, specifically to a tensile testing fixture and a tensile testing system for pultrusion bar-stitched composite material structures. Background Technology

[0002] Composite materials, due to their advantages of being lightweight, high-strength, corrosion-resistant, and highly designable, have been widely used in aerospace and civilian fields. With the increasing demands for lightweight and high reliability in aerospace and high-performance transportation, traditionally separated composite material structures are no longer sufficient to meet modern engineering requirements in terms of specific strength, interfacial reliability, and manufacturing efficiency. To overcome the shortcomings of laminates, such as easy delamination, limited fatigue performance, and weak mechanical properties at structural joints, pultruded bar-stitched composite material structures have emerged. This structure significantly enhances interlaminar shear strength and overall stiffness by embedding pultruded bars into the composite material layers and achieving interlaminar stitching, effectively suppressing delamination while improving impact resistance and fatigue performance. Compared with traditional mechanical fastening or local reinforcement methods, pultruded bar-stitched T-shaped composite material structures not only improve manufacturing efficiency and repeatability but also expand the application potential of composite materials in large structural components. Currently, this technology has demonstrated significant application value in areas such as aircraft fuselage skin and wing spars.

[0003] However, the mechanical performance testing fixture system for this structure is not yet perfect. Existing fixtures are mostly designed for plates or bars, which cannot meet the testing needs of pultruded bar stitched composite material structures. Utility Model Content

[0004] The purpose of this invention is to provide a tensile testing fixture and a tensile testing system for pultruded bar-stitched composite material structures, in order to solve the problem mentioned in the background art that there is no fixture suitable for tensile testing of pultruded bar-stitched composite material structures.

[0005] To solve the above-mentioned technical problems, in a first aspect, this utility model provides a tensile testing fixture, including a first fixture and a second fixture, wherein the first fixture and the second fixture are respectively used to clamp the two ends of the specimen, wherein: The first fixture includes a clamping block assembly and a first connector connected together. The first connector is used to connect to a test loading device. The clamping block assembly is provided with a clamping groove extending along a first direction. The clamping groove includes a clamping groove section and a connecting groove section. The connecting groove section connects the side wall of the clamping groove section and the outer end face of the clamping block assembly. The width of the clamping groove section is greater than the width of the connecting groove section. The second fixture includes a base, a limiting block assembly, and a second connector connected to each other. The second connector is used to connect to the test loading device. The limiting block assembly and the base form two limiting grooves extending along a first direction. The openings of the two limiting grooves are spaced apart and opposite to each other. The clamping groove and connecting groove are matched with one end of the specimen, and the two limiting grooves are matched with the other end of the specimen.

[0006] In some embodiments, the clamping block assembly includes a first clamping block and a second clamping block that are detachably connected. The first clamping block has a first recess, and the second clamping block has a corresponding second recess. The first recess and the second recess can be mated to form a clamping groove.

[0007] In some embodiments, the first connector includes a first link and a connecting seat that are connected to each other; The first clamping block is provided with a first assembly groove, and the second clamping block is provided with a second assembly groove. The first assembly groove and the second assembly groove can be connected to form an assembly space. The connecting seat is located in the assembly space, and in the length direction of the first connecting rod, the connecting seat is limited by the side wall of the assembly space.

[0008] In some embodiments, the connecting seat is provided with a limiting groove, and one end of the first connecting rod is connected to the bottom of the limiting groove; The first assembly groove has a first protrusion on its side wall and the second assembly groove has a second protrusion on its side wall. The first protrusion and the second protrusion can be joined together to form a limiting protrusion, which can be fitted into a limiting groove.

[0009] In some embodiments, a first inclined surface and a second inclined surface are respectively provided on the side walls on both sides of the limiting groove, and both the first inclined surface and the second inclined surface face the free end of the first connecting rod. A third inclined surface and a fourth inclined surface are respectively provided on the side walls on both sides of the limiting protrusion, the third inclined surface is adapted to the first inclined surface, and the fourth inclined surface is adapted to the second inclined surface.

[0010] In some embodiments, the sidewalls of the first protrusion and the second protrusion abut against each other, and the width of the bottom of the limiting groove is smaller than the width of the top of the limiting protrusion.

[0011] In some embodiments, the clamping block assembly has a through hole that connects the assembly space and the outer end face of the first clamp, the first connecting rod passes through the through hole, and at least a portion of the first connecting rod protrudes from the outer end face of the first clamp.

[0012] In some embodiments, the first connecting rod, the clamping groove segment, and the connecting groove segment are collinear in a cross section perpendicular to the first direction.

[0013] In some embodiments, the limiting block assembly includes a first limiting block and a second limiting block spaced apart along a second direction. The first limiting block and the base enclose a first limiting groove, and the second limiting block and the base enclose a second limiting groove. The openings of the first limiting groove and the second limiting groove are spaced apart and opposite to each other.

[0014] In some embodiments, the base is provided with at least two first mounting structures and at least two second mounting structures spaced apart along a second direction, wherein the first mounting structures are used to connect to the first limiting block and the second mounting structures are used to connect to the second limiting block.

[0015] In some embodiments, the clamping block assembly has opposing first and second end faces, at least a portion of the first connector protrudes from the first end face, and the connecting groove segment communicates with the sidewall of the clamping groove segment and the second end face.

[0016] In some embodiments, the base has opposing third and fourth end faces, at least a portion of the second connector protrudes from the fourth end face, and the limiting block assembly and the third end face form two limiting grooves extending in a first direction.

[0017] In a second aspect, this utility model provides a tensile testing system for pultruded bar-stitched composite material structures, including a specimen and the tensile testing fixture described above. The specimen includes a pultruded bar portion and a composite material portion. The composite material portion includes a first plate and a second plate. One end of the second plate is connected to the middle of the first plate, and the pultruded bar portion is connected to the end of the second plate away from the first plate. The pultruded bar portion is fitted and fixed in a clamping groove, and both ends of the first plate are fitted and fixed in two limiting grooves respectively.

[0018] Compared with the prior art, the beneficial effects of this utility model are: The tensile testing fixture of this invention includes a first fixture and a second fixture, both with connecting parts. A clamping groove is provided on the first fixture, and two limiting grooves are provided on the second fixture. The clamping groove clamps the pultruded rod portion of the pultruded rod-stitched composite material structure, and the two limiting grooves clamp the composite material portion of the pultruded rod-stitched T-shaped composite material structure. This allows the first and second fixtures to respectively clamp both ends of the pultruded rod-stitched composite material structure, enabling the testing personnel to install the pultruded rod-stitched composite material structure onto the testing loading device for tensile testing. Through the mutual cooperation and connection of its components, this invention provides a simple and practical way to reliably fix the pultruded rod-stitched composite material structure during tensile loading, providing equipment support for the tensile performance testing of pultruded rod-stitched composite material structures. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced one by one below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other embodiments and drawings can be obtained based on these drawings without creative effort. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0020] Figure 1 This is a front view of the tensile testing fixture and specimen described in the embodiments of this application; Figure 2 This is a schematic diagram of the tensile testing fixture and specimen described in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the first clamp in the embodiment of this application; Figure 4 This is a schematic diagram of the clamping block assembly described in an embodiment of this application; Figure 5 This is a front view schematic diagram of the clamping block assembly described in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of the first connector in an embodiment of this application; Figure 7 This is a front view of the first connector in an embodiment of this application; Figure 8 This is a front view of the second fixture in an embodiment of this application; Figure 9 This is a schematic diagram of the structure of the base and the second connector described in the embodiments of this application; Figure 10 This is a schematic diagram of the structure of the specimen described in the embodiments of this application.

[0021] Figure label: 1-First clamp; 11-Clamping block assembly; 111 - First end face; 112 - Second end face; 113-Clamping groove; 1131 - Clamping groove section; 1132 - Connecting groove section; 114 - First clamping block; 115 - Second clamping block; 116 - Assembly space; 117 - Limiting protrusion; 1171 - First protrusion; 1172 - Second protrusion; 1173 - Third slope; 1174 - Fourth slope; 118 - Through hole; 12-First connector; 121 - First Link; 122-Connector; 1221 - Limiting groove; 1222 - First inclined surface; 1223 - Second inclined surface; 2-Second clamp; 21-Base; 211 - Third end face; 212 - Fourth end face; 213 - First mounting structure; 214 - Second mounting structure; 22-Limit block assembly; 221 - First limit block; 222 - Second limit block; 223 - First limiting groove; 224 - Second limiting groove; 23-Second connector; 3-Specimen; 31 - Pultrusion bar section; 32-Composite Material Section; 321 - First plate; 322 - Second plate. Detailed Implementation

[0022] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application. The described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, they can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] This application is described below with reference to the accompanying drawings and specific embodiments: A first aspect of this application provides a tensile testing fixture, such as... Figure 1 and Figure 2 As shown, it includes a first clamp 1 and a second clamp 2, which are used to clamp the two ends of the specimen 3 for tensile testing.

[0024] In an optional implementation, combined with Figure 10Specimen 3 is a pultruded bar-stitched composite material structure, specifically including a pultruded bar portion 31 and a composite material portion 32. The composite material portion 32 includes a first plate 321 and a second plate 322. One end of the second plate 322 is connected to the middle of the first plate 321, and the pultruded bar portion 31 is connected to the end of the second plate 322 away from the first plate 321. The width of the pultruded bar portion 31 is greater than the width of the second plate 322. Exemplarily, specimen 3 is a strip structure extending along a first direction. The cross-section of the pultruded bar portion 31 is circular, and the cross-section of the composite material portion 32 is T-shaped. The pultruded bar portion 31 is located at the end of the middle plate of the T-shaped composite material portion 32.

[0025] In some embodiments, combined with Figure 3 The first clamp 1 includes a clamping block assembly 11 and a first connector 12 connected to each other. The first connector 12 is used to connect to a test loading device, so that the test loading device applies a tensile force to the specimen 3 clamped by the clamping block assembly 11.

[0026] In some embodiments, further, combined Figure 4 and Figure 5 The clamping block assembly 11 is provided with a clamping groove 113, which extends along a first direction to allow it to fit into and cooperate with the strip structure, thereby clamping the strip structure, such as the specimen 3 described above. Furthermore, the clamping groove 113 has a clamping groove section 1131 and a connecting groove section 1132, both extending along the first direction. The connecting groove section 1132 connects the sidewall of the clamping groove section 1131 and the clamping block assembly. One of the outer end faces of component 11 has a clamping groove 1131 with a width greater than that of the connecting groove 1132, so that the clamping groove 113 can clamp components with a width greater than that of the connecting groove 1132 and smaller than that of the clamping groove 1131. For example, for the specimen 3 described above, the pultruded rod portion 31 with a larger width can be limited by the clamping groove 1131, and the second plate 322 of the composite material portion 32 with a slightly smaller width can extend out of the outer end face of the clamping block assembly 11 along the connecting groove 1132.

[0027] Combination Figure 2 The horizontal direction described in this embodiment is Figure 2 The second direction is perpendicular to the first direction; in this embodiment, a third direction is defined to be perpendicular to both the first and second directions.

[0028] In an optional embodiment, in order to reduce the lateral displacement between the clamping block assembly 11 and the specimen 3, the cross-section of the clamping groove section 1131 is adapted to the cross-section of the pultrusion rod portion 31, that is, their shapes and sizes are similar. In order to accommodate the pultrusion rod portion 31, the cross-sectional size of the clamping groove section 1131 is slightly larger than the cross-sectional size of the pultrusion rod portion 31. Exemplarily, the cross-section of the clamping groove section 1131 is a circle that is slightly larger than the cross-section of the pultrusion rod portion 31.

[0029] In an optional implementation, combined with Figure 1 The clamping block assembly 11 has a first end face 111 and a second end face 112 opposite to each other. At least a portion of the first connector 12 protrudes from the first end face 111. The connecting groove segment 1132 connects the side wall of the clamping groove segment 1131 and the second end face 112. That is, the openings of the first connector 12 and the clamping groove 113 are respectively set on opposite sides of the clamping block assembly 11, so that the test loading device can apply a tensile force to the specimen 3 that is fitted with the clamping groove 113 for tensile testing.

[0030] In some embodiments, combined with Figure 4 The clamping block assembly 11 includes a first clamping block 114 and a second clamping block 115 that are detachably connected. The first clamping block 114 has a first recess, and the second clamping block 115 has a corresponding second recess. The first and second recesses can be joined to form a clamping groove 113. The clamping groove 113 is formed by two recesses, which facilitates the placement of the pultruded rod portion 31, whose lateral width is greater than that of the connecting groove section 1132, into the clamping groove section 1131. It also facilitates the selection of the first clamping block 114 and the second clamping block 115 with corresponding recesses according to the size of the specimen 3 to form the clamping groove 113. In particular, when there is a deviation in the size of the pultruded rod portion 31, such as when the left and right sides are different sizes, the first clamping block 114 and the second clamping block 115 with corresponding recesses can be selected according to the size of the left and right sides of the pultruded rod portion 31 to form the clamping groove 113. This helps to keep the force on both sides of the pultruded rod portion 31 uniform during loading and maintain the accuracy of the tensile force direction.

[0031] In an optional embodiment, a fixing member is further included, which is used to fix the first clamping block 114 and the second clamping block 115. Exemplarily, the fixing member includes a screw and a nut. The first clamping block 114 and the second clamping block 115 are respectively provided with a plurality of through holes. The screw passes through the through holes on the first clamping block 114 and the second clamping block 115 in sequence and is fixedly connected to the nut. The nut is located on the outer side wall of the first clamping block 114 and the second clamping block 115, thereby restricting the separation of the first clamping block 114 and the second clamping block 115 by means of the nut.

[0032] In some embodiments, further, combined Figure 4 , Figure 6 and Figure 7 The first connector 12 includes a first connecting rod 121 and a connecting seat 122 connected to each other. The connecting seat 122 can extend along a first direction. A first mounting groove is provided on a first clamping block 114, and a second mounting groove is provided on a second clamping block 115. The first mounting groove and the second mounting groove can be connected to form an assembly space 116. The connecting seat 122 is located in the assembly space 116, and in the length direction of the first connecting rod 121, the connecting seat 122 is limited by the side wall of the assembly space 116.

[0033] The first connecting rod 121 can be a cylinder with a cross-sectional shape adapted to the clamping head on the test loading device, for example, the first connecting rod 121 can be a cylinder; one end of the first connecting rod 121 can be connected to the connecting seat 122, and the other end away from the connecting seat 122 can be connected to the test loading device; the connecting seat 122 is located in the assembly space 116 and is limited by the side wall of the assembly space 116, so that the test loading device can apply a pulling force to the clamping block assembly 11 by pulling the first connecting rod 121; moreover, the above structure allows the first clamping block 114, the second clamping block 115 and the first connecting member 12 to be detachably connected, which makes it convenient for testers to adapt the size of the specimen 3 by replacing the first clamping block 114 and the second clamping block 115 without replacing the entire first clamp 1, which helps to reduce costs; at the same time, during the replacement of the first clamping block 114 and the second clamping block 115, the first connecting rod 121 does not need to be removed from the test loading device, which helps to simplify the test procedure.

[0034] In an optional implementation, combined with Figure 4 In order for the first connecting rod 121 connected to the connecting seat 122 to extend out of the clamping block assembly 11 to connect with the test loading device, the clamping block assembly 11 is provided with a through hole 118 that connects the assembly space 116 and the outer end face of the first clamp 1. The first connecting rod 121 passes through the through hole 118, and at least a portion of the first connecting rod 121 protrudes from the outer end face of the first clamp 1.

[0035] In an optional embodiment, to minimize the bending moment on specimen 3 during the tensile test and ensure that the test results accurately reflect the tensile strength of specimen 3, the first connecting rod 121, the clamping groove segment 1131, and the connecting groove segment 1132 are collinear on the cross section perpendicular to the first direction. Furthermore, in the first direction, the first connecting rod 121 is located at the midpoint of the clamping block assembly 11.

[0036] In some embodiments, combined with Figure 5 and Figure 6 To reduce the shaking between the clamping block assembly 11 and the first connecting member 12 and improve the test accuracy and stability, the connecting seat 122 is provided with a limiting groove 1221. One end of the first connecting rod 121 is connected to the bottom of the limiting groove 1221. A first protrusion 1171 is provided on the side wall of the first assembly groove, which is located on the side wall of the first assembly groove near the first end face 111. A second protrusion 1172 is provided on the side wall of the second assembly groove, which is located on the side wall of the second assembly groove near the first end face 111. The first protrusion 1171 and the second protrusion 1172 can be connected to form a limiting protrusion 117, which can be fitted into the limiting groove 1221.

[0037] By engaging the limiting protrusion 117 formed by the first protrusion 1171 and the second protrusion 1172 with the limiting groove 1221, the misalignment of the clamping block assembly 11 and the first connecting member 12 in the lateral direction can be reduced, thereby reducing the lateral displacement of the specimen 3 held by the clamping block assembly 11 relative to the test loading device, which is conducive to maintaining the positional stability of the specimen 3 relative to the test loading device and improving the test accuracy.

[0038] Considering that the limiting protrusion 117 and the limiting groove 1221 with vertical sidewalls need to have a certain gap when assembled and connected, and the existence of the gap will weaken the lateral positional stability of the clamping block assembly 11 and the first connecting member 12, in some embodiments, the sidewalls on both sides of the limiting groove 1221 are respectively provided with a first inclined surface 1222 and a second inclined surface 1223. The first inclined surface 1222 and the second inclined surface 1223 are both facing the free end of the first connecting rod 121, that is, the first inclined surface 1222 and the second inclined surface 1223 are away from the bottom surface of the limiting groove 1221; the sidewalls on both sides of the limiting protrusion 117 are respectively provided with a third inclined surface 1173 and a fourth inclined surface 1174. The third inclined surface 1173 is adapted to the first inclined surface 1222, and the fourth inclined surface 1174 is adapted to the second inclined surface 1223.

[0039] Furthermore, the width of the bottom of the limiting groove 1221 is less than the width of the top of the limiting protrusion 117.

[0040] During assembly, due to the large size of the groove opening of the limiting groove 1221, the first protrusion 1171 and the second protrusion 1172 can be easily embedded into the limiting groove 1221, and the third inclined surface 1173 abuts against the first inclined surface 1222, and the fourth inclined surface 1174 abuts against the second inclined surface 1223. As the tensile force gradually increases during loading, the gap between the abutting inclined surfaces becomes smaller and smaller, making it more difficult for the limiting protrusion 117 and the limiting groove 1221 to undergo lateral relative displacement, and the lateral position of the clamping block assembly 11 and the first connecting member 12 becomes more stable. Moreover, when the tensile force gradually increases, the gap between the two abutting inclined surfaces becomes very small, and the left and right deviations of the limiting protrusion 117 and the limiting groove 1221 become very small, which helps to reduce the left and right deviations of the clamping block assembly 11 and the first connecting member 12.

[0041] In an optional implementation, combined with Figure 5 The sidewalls of the first protrusion 1171 and the second protrusion 1172 abut against each other. By abutting against each other, a large compressive force can be generated between the first protrusion 1171 and the second protrusion 1172, which helps to limit the relative rotation between the first clamping block 114 and the second clamping block 115. Furthermore, on the side of the assembly space near the second end face 112, the first clamping block 114 and the second clamping block 115 have a contact surface, which is used to limit the relative rotation between the first clamping block 114 and the second clamping block 115.

[0042] In an optional embodiment, the first clamping block 114 and the second clamping block 115 are symmetrical, and the symmetrical structure has higher uniformity, which is beneficial to improving the test accuracy.

[0043] In some embodiments, combined with Figure 8 and Figure 9 The second clamp 2 includes a base 21, a limiting block assembly 22, and a second connector 23 connected to each other. The second connector 23 is used to connect to the test loading device. The limiting block assembly 22 and the base 21 form two limiting grooves extending along the first direction. The openings of the two limiting grooves are spaced apart and opposite to each other. The two limiting grooves can be used to limit the two ends of the first plate 321 of the composite material part 32, respectively.

[0044] In an optional embodiment, the base 21 has a third end face 211 and a fourth end face 212 opposite to each other, at least a portion of the second connector 23 protrudes from the fourth end face 212, and the limiting block assembly 22 and the third end face 211 form two limiting grooves extending in a first direction.

[0045] In an optional embodiment, the base 21 is a flat plate structure, and the second connector 23 is a column whose cross-sectional shape is adapted to the clamping head on the test loading device, such as a cylinder. The second connector 23 protrudes from the surface of the base 21 and is connected to the test loading device through the protruding part.

[0046] In an optional implementation, combined with Figure 8 The limiting block assembly 22 includes a first limiting block 221 and a second limiting block 222 spaced apart along a second direction. The first limiting block 221 and the base 21 enclose a first limiting groove 223, and the second limiting block 222 and the base 21 enclose a second limiting groove 224. The openings of the first limiting groove 223 and the second limiting groove 224 are spaced apart and opposite to each other. Exemplarily, the cross-sectional shape of the first limiting block 221 and the second limiting block 222 is L-shaped. They both include a plate body 1 and a plate body 2 connected at their ends and perpendicular to each other. The end of plate body 1 away from plate body 2 is connected to the base 21, and plate body 2 is spaced apart from the base 21. Plate body 1, plate body 2, and the base 21 together enclose a limiting groove, and the opening of the limiting groove is opposite to plate body 1. By inserting the end of the first plate 321 of the composite material part 32 into the limiting groove, the displacement of the first plate 321 in the third direction can be limited by the second plate; furthermore, by making the distance between the two plates similar to the width of the first plate 321, the displacement of the first plate 321 in the second direction can be further limited, thereby limiting the lateral displacement of the specimen 3 relative to the test loading device.

[0047] Furthermore, the first limiting block 221 and the second limiting block 222 are detachably connected to the base 21, which makes it convenient to adapt the first plate 321 of different thicknesses by replacing the first limiting block 221 and the second limiting block 222 of different specifications.

[0048] In some embodiments, the first limiting block 221 and the second limiting block 222 are detachably connected to the base 21, facilitating the installation of the first plate 321 in the two limiting grooves. Further, the base 21 is provided with at least two first mounting structures 213 and at least two second mounting structures 214 spaced apart along a second direction. The first mounting structures 213 are used to connect the first limiting block 221, and the second mounting structures 214 are used to connect the second limiting block 222. By providing multiple first mounting structures 213 and second mounting structures 214 spaced apart along the second direction, the distance between the first limiting block 221 and the second limiting block 222 can be adjusted, allowing the second clamp 2 to adapt to composite material parts 32 of different sizes.

[0049] In the example, the first mounting structure 213 and the second mounting structure 214 are both several through holes extending along the first direction, and the first limiting block 221 and the second limiting block 222 can be fixed to the base 21 using screws.

[0050] The tensile testing fixture described in this embodiment, by providing a plurality of first mounting structures 213 and a plurality of second mounting structures 214 on the base 21, and by setting the limiting block to the base 21, and the first clamping block 114, the second clamping block 115, and the first connecting member 12 to be detachably connected, enables the tensile testing fixture to have an adjustable size function, which can flexibly adapt to specimens of different sizes, significantly expand the scope of application of the test, and effectively improve the accuracy and repeatability of the test results. A second aspect of this application provides a tensile testing system for pultruded bar-stitched composite material structures, including a specimen 3 and a tensile testing fixture as described above.

[0051] In some embodiments, combined with Figure 10 The specimen 3 includes a pultrusion bar portion 31 and a composite material portion 32. The composite material portion 32 includes a first plate 321 and a second plate 322. One end of the second plate 322 is connected to the middle of the first plate 321, and the pultrusion bar portion 31 is connected to the end of the second plate 322 away from the first plate 321. The width of the pultrusion bar portion 31 is greater than the width of the second plate 322.

[0052] Combination Figure 1 and Figure 2 During clamping, the pultrusion rod 31 is fitted and fixed in the clamping groove 113, and the two ends of the first plate 321 are fitted and fixed in the two limiting grooves respectively. The first connector and the second connector are respectively connected to the two clamping heads on the test loading device.

[0053] Regarding the specific implementation methods of this application, it should be noted that: In the description of this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, or readable storage medium that comprises a list of elements includes not only those elements but also other elements not expressly listed that conform to the concept of this application, or elements inherent to such a process, method, apparatus, or readable storage medium. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of additional elements in the process, method, apparatus, or readable storage medium that includes said element.

[0054] In the description of this application, the use of terms such as "some embodiments," "optional embodiments," "example," "specific example," "optional example," or "optional embodiment," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application, but does not imply that these embodiments illustrate and describe all possible forms of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0055] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments; the above description should not be construed as a limitation of the present invention. Technical solutions between various embodiments can be combined with each other, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application. Although embodiments of the present application have been shown and described, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. Those skilled in the art will understand that various other specific changes and combinations of embodiments based on the technical teachings disclosed in this application, without departing from the essence of the present application, are still within the scope of protection defined by the claims of the present invention and their equivalent technical solutions.

Claims

1. A tensile testing fixture, characterized in that, Includes a first clamp (1) and a second clamp (2), the first clamp (1) and the second clamp (2) being used to clamp the two ends of the specimen (3), wherein: The first clamp (1) includes a clamping block assembly (11) and a first connector (12) connected to each other. The first connector (12) is used to connect to a test loading device. The clamping block assembly (11) is provided with a clamping groove (113) extending in a first direction. The clamping groove (113) includes a clamping groove section (1131) and a connecting groove section (1132). The connecting groove section (1132) connects the side wall of the clamping groove section (1131) and the outer end face of the clamping block assembly (11). The width of the clamping groove section (1131) is greater than the width of the connecting groove section (1132). The second fixture (2) includes a base (21), a limiting block assembly (22), and a second connector (23) connected together. The second connector (23) is used to connect to the test loading device. The limiting block assembly (22) and the base (21) form two limiting grooves extending in a first direction. The openings of the two limiting grooves are spaced apart and opposite to each other. The clamping groove (1131) and the connecting groove (1132) are matched with one end of the specimen (3), and the two limiting grooves are matched with the other end of the specimen (3).

2. The tensile testing fixture according to claim 1, characterized in that: The clamping block assembly (11) includes a first clamping block (114) and a second clamping block (115) that are detachably connected. The first clamping block (114) has a first recess, and the second clamping block (115) has a corresponding second recess. The first recess and the second recess can be connected to form the clamping groove (113).

3. A tensile testing fixture according to claim 2, characterized in that: The first connector (12) includes a first connecting rod (121) and a connecting seat (122) connected to each other. The first clamping block (114) is provided with a first assembly groove, and the second clamping block (115) is provided with a second assembly groove. The first assembly groove and the second assembly groove can be connected to form an assembly space (116). The connecting seat (122) is located in the assembly space (116), and in the length direction of the first connecting rod (121), the connecting seat (122) is limited by the side wall of the assembly space (116).

4. A tensile testing fixture according to claim 3, characterized in that: The connecting seat (122) is provided with a limiting groove (1221), and one end of the first connecting rod (121) is connected to the bottom of the limiting groove (1221); The first assembly groove has a first protrusion (1171) on its side wall and the second assembly groove has a second protrusion (1172) on its side wall. The first protrusion (1171) and the second protrusion (1172) can be connected to form a limiting protrusion (117), and the limiting protrusion (117) can be fitted into the limiting groove (1221).

5. A tensile testing fixture according to claim 4, characterized in that: The side walls on both sides of the limiting groove (1221) are provided with a first inclined surface (1222) and a second inclined surface (1223), respectively. The first inclined surface (1222) and the second inclined surface (1223) are both facing the free end of the first connecting rod (121). The side walls on both sides of the limiting protrusion (117) are provided with a third inclined surface (1173) and a fourth inclined surface (1174), respectively. The third inclined surface (1173) is adapted to the first inclined surface (1222), and the fourth inclined surface (1174) is adapted to the second inclined surface (1223).

6. A tensile testing fixture according to claim 5, characterized in that: The sidewalls of the first protrusion (1171) and the second protrusion (1172) are in contact with each other, and the width of the bottom of the limiting groove (1221) is smaller than the width of the top of the limiting protrusion (117).

7. A tensile testing fixture according to claim 3, characterized in that: The clamping block assembly (11) is provided with a through hole (118) connecting the assembly space (116) and the outer end face of the first clamp (1). The first connecting rod (121) passes through the through hole (118), and at least a portion of the first connecting rod (121) protrudes from the outer end face of the first clamp (1). In a cross section perpendicular to the first direction, the first connecting rod (121), the clamping groove section (1131), and the connecting groove section (1132) are collinear.

8. A tensile testing fixture according to any one of claims 1-7, characterized in that: The limiting block assembly (22) includes a first limiting block (221) and a second limiting block (222) spaced apart along a second direction. The first limiting block (221) and the base (21) enclose a first limiting groove (223), and the second limiting block (222) and the base (21) enclose a second limiting groove (224). The openings of the first limiting groove (223) and the second limiting groove (224) are spaced apart and opposite to each other. The base (21) is provided with at least two first mounting structures (213) and at least two second mounting structures (214) spaced apart along the second direction. The first mounting structure (213) is used to connect the first limiting block (221), and the second mounting structure (214) is used to connect the second limiting block (222).

9. A tensile testing fixture according to claim 1, characterized in that: The clamping block assembly (11) has a first end face (111) and a second end face (112) opposite each other, at least a portion of the first connector (12) protrudes from the first end face (111), and the connecting groove segment (1132) communicates the side wall of the clamping groove segment (1131) and the second end face (112). The base (21) has opposing third end face (211) and fourth end face (212), at least a portion of the second connector (23) protrudes from the fourth end face (212), and the limiting block assembly (22) and the third end face (211) form two limiting grooves extending in a first direction.

10. A tensile testing system for pultruded bar-stitched composite material structures, characterized in that, The test specimen (3) includes a test piece (3) and a tensile test fixture as described in any one of claims 1-9. The test piece (3) includes a pultrusion bar portion (31) and a composite material portion (32). The composite material portion (32) includes a first plate (321) and a second plate (322). One end of the second plate (322) is connected to the middle of the first plate (321), and the pultrusion bar portion (31) is connected to the end of the second plate (322) away from the first plate (321). The pultrusion rod (31) is fitted and fixed in the clamping groove (113), and the two ends of the first plate (321) are respectively fitted and fixed in the two limiting grooves.

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