Composite beam and teaching aid therefor

Abstract

The present application relates to the technical field of laminated beam structure, and provides a composite beam and teaching aid thereof, which comprises a plurality of beams and split wedge block assemblies, the beams are provided with wedge block holes, and the plurality of beams are arranged in a laminated manner, and the split wedge block assemblies are fitted into the wedge block holes and can lock the beams of each layer. The split wedge block assembly comprises an adjusting member and at least one wedge block group, the wedge block group is provided with a plurality of wedge-shaped sliders, and the adjusting member is connected with the wedge block group, so that each wedge-shaped slider can move relatively along the extension direction of the wedge surface. The composite beam is designed in a modular manner, i.e. a single beam and a split wedge block assembly, and the single beam and the split wedge block assembly are combined and locked to form the composite beam, so that the single beam can be replaced or added quickly and conveniently, different combination modes can be realized quickly, the combination flexibility of the composite beam is improved, and the stiffness and structural strength of the beam can be changed quickly by adding or replacing the single beam.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laminated beam structure, and particularly relates to a composite beam and teaching aid thereof. BACKGROUND

[0002] In order to fully exert the elastic performance and bearing capacity of different performance materials or some special use functions, a plurality of beams are laminated to form a laminated composite beam, which is a commonly used way in engineering. The replacement or addition or subtraction of a single beam in the laminated beam will change the stiffness and structural strength of the composite beam. In some scenarios, different stiffness and structural strength are needed to meet different functional requirements.

[0003] However, the existing laminated beam is usually connected by fixed connection when connecting each layer of beam. This connection method is complicated when adding or replacing each layer of beam, which is not conducive to quick operation or cannot replace the layer beam structure on site, so that the change of the stiffness and structural strength of the composite beam cannot be quickly realized. For example, as a teaching aid, it needs to test various materials in various laminated forms within a limited teaching time, which requires frequent switching to verify or understand the advantages of various materials in the laminated beam in engineering. It is obvious that the existing fixed connection method cannot achieve the purpose of free switching and cannot provide flexible combination. Therefore, how to quickly realize the change and replacement of the laminated beam is an important issue to be solved at present. SUMMARY

[0004] The present application provides a composite beam and teaching aid thereof to solve the defect that the single beam, wedge block beam and layer beam of the same and different materials cannot be freely and quickly switched in the prior art.

[0005] The present application provides a composite beam, comprising: a plurality of beams and a split wedge block assembly;

[0006] The beam has a wedge block hole, and the plurality of beams are arranged in a laminated manner;

[0007] The split wedge block assembly is fitted in the wedge block hole and can lock the beams of each layer;

[0008] The split wedge block assembly comprises an adjusting member and at least one wedge block group, the wedge block group has a plurality of wedge-shaped sliders, and the adjusting member is connected with the wedge block group to enable the wedge-shaped sliders to relatively move along the extension direction of the wedge surface.

[0009] According to the composite beam provided by the present application, the adjusting member comprises an adjusting bolt, and at least one of the wedge-shaped sliders has a thread matched with the adjusting bolt.

[0010] The wedge block group is two groups, namely a first wedge block group and a second wedge block group.

[0011] The first wedge block group is connected with the adjusting screw, and the first wedge block group and the second wedge block group abut each other, so that the first wedge block group and the second wedge block group can expand or contract outward under the action of the adjusting screw.

[0012] The first wedge block group comprises a first wedge-shaped sliding block and a second wedge-shaped sliding block, and the second wedge block group comprises a third wedge-shaped sliding block and a fourth wedge-shaped sliding block.

[0013] The first wedge-shaped sliding block and the second wedge-shaped sliding block are connected on the adjusting screw, so that the first wedge-shaped sliding block and the second wedge-shaped sliding block can move axially relative to each other along the adjusting screw.

[0014] The third wedge-shaped sliding block and the fourth wedge-shaped sliding block are respectively arranged on the two sides of the first wedge-shaped sliding block and the second wedge-shaped sliding block, and the wedge-shaped surfaces on the third wedge-shaped sliding block and the fourth wedge-shaped sliding block are in contact with the wedge-shaped surfaces on the first wedge-shaped sliding block and the second wedge-shaped sliding block, so that the third wedge-shaped sliding block and the fourth wedge-shaped sliding block can expand or contract outward along the two sides.

[0015] The first wedge-shaped sliding block is located at the upper end between the third wedge-shaped sliding block and the fourth wedge-shaped sliding block, and the second wedge-shaped sliding block is located at the lower end between the third wedge-shaped sliding block and the fourth wedge-shaped sliding block.

[0016] The beam of each layer is a single-layer beam or a multi-layer beam.

[0017] The beam has a plurality of wedge block holes.

[0018] The present application also provides a teaching aid suitable for material strain testing, comprising the composite beam of any one of the above embodiments.

[0019] The present application also provides a teaching aid suitable for material strain testing, comprising the composite beam of any one of the above embodiments.

[0020] According to any one of the above embodiments, the present application has at least the following beneficial effects:

[0021] The composite beam provided by the application is designed in a modular manner, i.e., a single beam and a split wedge assembly, and is combined and locked or loosened by a plurality of single beams and split wedge assemblies to form a fixed composite beam or a laminated beam (without fixation) composite beam, so that the single beam can be replaced or added quickly and conveniently, different combination modes can be quickly realized, the combination flexibility of the composite beam is improved, and the stiffness and structural strength of the beam can be quickly changed by increasing, decreasing or replacing the single beam. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0023] Figure 1 is one of the structural schematic diagrams of the composite beam provided by the application.

[0024] Figure 2 is one of the structural schematic diagrams of the split wedge assembly provided by the application.

[0025] Figure 3 is the second structural schematic diagram of the composite beam provided by the application.

[0026] Figure 4 is the second structural schematic diagram of the split wedge assembly provided by the application.

[0027] Figure 5 is the third structural schematic diagram of the split wedge assembly provided by the application.

[0028] Reference signs:

[0029] 110: XX; 120: YY; 130: ZZ. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the application more clear, the technical solutions in the application will be described clearly and completely below in combination with the drawings in the application. Obviously, the described embodiments are some embodiments of the application, not all embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0031] In order to make the objects, technical solutions and advantages of the present application clearer, the following will be combined with the accompanying drawings for the purpose of making the technical solutions in the present application clearer, complete and more comprehensible. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0032] In the description of the embodiments of the present application, it should be noted that the positions or position relationships indicated by the terms "upper", "lower" and the like are based on the positions or position relationships shown in the drawings, and are only for the purpose of facilitating the description of the embodiments of the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular position, be constructed and operated in a particular position, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third", "fourth" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0033] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the term "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above-mentioned term in the embodiments of the present application can be understood according to the specific circumstances.

[0034] In the description of the present application, the description of the terms "specific embodiments", "some embodiments", "specific examples" and the like means that the specific features, structures, materials or characteristics described in combination with the embodiments or examples are contained in at least one embodiment or example of the embodiments of the present application. In the present application, the illustrative description of the above-mentioned terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those of ordinary skill in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction. In addition, the plurality of representations in the present application means two or more.

[0035] In some existing possible embodiments, the laminated beam is directly connected by bolts or other fasteners, and such connection has poor stability and weak shear strength, and the actual performance of the laminated beam is not accurately reflected, so that the overall performance of the laminated beam is weak. Therefore, it is necessary to change the traditional fastening mode of the laminated beam to be able to meet the quick replacement and high-performance laminated beam structure.

[0036] The following will be described in combination with Figures 1-2The application discloses a composite beam which is suitable for scenarios requiring rapid change of the rigidity of the composite beam. The composite beam comprises a plurality of beams 100 and a split wedge assembly 200, the beams 100 are provided with wedge holes, and the beams 100 are arranged in a stacked manner, and the split wedge assembly 200 is fitted into the wedge holes and can lock the beams 100 of each layer. The split wedge assembly 200 comprises an adjusting member 202 and at least one wedge group 201, the wedge group 201 is composed of two wedge-shaped sliding blocks, and the adjusting member 202 is connected with the wedge group 201 so that the wedge-shaped sliding blocks can move relatively along the extension direction of the wedge surface.

[0037] The composite beam is constructed in a modular form, the wedge holes are arranged on each single beam, the split wedge assembly 200 can be fitted into the wedge holes, and the split wedge assembly 200 fitted into the wedge holes can be in close contact with the inner wall of the wedge holes in a locked state to form an interference fit, so that the locking stability is stronger. The adjusting member 202 is suitable for driving the split wedge assembly 200 to act, so that the single beams of each layer can be locked or unlocked, the replacement or increase or decrease of different single beams is realized, and the rigidity and structural strength of the composite beam structure can be rapidly changed.

[0038] The wedge holes can be in various forms, for example, round holes, square holes, oval holes, special-shaped holes and the like. The wedge holes on each single beam are on the same axis when the single beams are stacked to form the composite beam. The outer shape structure of the wedge-shaped sliding blocks in the wedge group 201 is correspondingly arranged according to the selected wedge-shaped holes, for example, when the wedge-shaped holes are selected as round holes, the outer wall of the wedge-shaped sliding blocks is an arc-shaped outer wall concentric with the round holes, so that the wedge assembly can be stably locked when locked. Certainly, it can be foreseen that the adjusting member 202 can also realize the unlocking operation between the single beams of each layer. Because the locking of the relative expansion of the wedge-shaped sliding blocks can also realize the unlocking of the relative contraction.

[0039] It can be understood that, in order to lock all the stacked beams, the size of the wedge-shaped sliding blocks directly in contact with the inner wall of the wedge hole needs to satisfy that the total length is greater than or equal to the height of all the stacked single beams, so that the wedge-shaped sliding blocks in the wedge group 201 can be in contact with the inner wall of the wedge hole of each single beam when locked. Obviously, in this way, even when the middle part of the composite beam is stressed, the wedge group 201 can still provide good shear strength.

[0040] In specific examples, the number and shape of beams 100 in the composite beam are not limited; there can be two or more beams, which can be single beams or layered beams. The materials of the beams 100 in the layered beams can be the same or different, and they can be rectangular beams or beams of other shapes. Each beam is stacked to form a layered composite beam. The material of each single beam in each layer is not limited; it can be beams 100 of the same material, beams 100 of different materials, or a combination of two materials alternating between each other.

[0041] For a specific example, the location of the wedge hole can be selected based on the length of the single beam. For instance, if the single beam is long, wedge holes can be made at both ends and the middle of the beam 100 for locking via the split wedge assembly 200. If the single beam is generally short, wedge holes can be made at both ends of the beam 100 for locking via the split wedge assembly 200.

[0042] In some embodiments, the adjusting member 202 is an adjusting bolt, and at least one wedge slider has threads that match the adjusting bolt.

[0043] By adjusting the fit between the bolt and the wedge slider, the wedge slider will move along the axial direction of the bolt when the bolt is rotated. When moving along the axial direction, the wedge surface on one wedge slider will act on the wedge surface on the other wedge slider, which causes the other wedge slider to move relative to each other, so that the two sides of the wedge block assembly 201 will expand or contract.

[0044] The composite beam provided by the present invention will be described below through specific embodiments.

[0045] Example 1

[0046] like Figure 1 As shown, a composite beam includes two beams 100 and two sets of separate wedge block assemblies 200. Wedge holes are machined at both ends of the beams 100. The two beams 100 are arranged in a stacked manner. The two sets of separate wedge block assemblies 200 are fitted into the wedge holes and can lock each layer of beams 100. Each separate wedge block assembly 200 includes an adjusting bolt and a set of wedge blocks 201. The wedge block set 201 consists of two wedge-shaped sliders. The adjusting bolt is connected to one of the wedge-shaped sliders located at the lower end, allowing one of the wedge-shaped sliders to move along the extension direction of the wedge surface. This causes relative movement between the two wedge-shaped sliders, achieving locking or unlocking between the layers of beams 100.

[0047] In the above embodiment, beam 100 is a rectangular beam, and the wedge hole is a rectangular hole with chamfered edges around the perimeter. Correspondingly, the outer wall of the wedge slider is a rectangular plane. By rotating the adjusting bolt, the lower wedge slider moves along the bolt's axial direction, causing another wedge slider to move along the wedge surface. This changes the width of the wedge slider (perpendicular to the axial direction of the adjusting bolt), allowing the wedge slider to move and engage with the inner wall of the wedge hole, thus securing it with an interference fit between the wedge slider and the wedge hole on beam 100. Loosening the bolt reduces the width between the wedge sliders, loosening the engagement between the wedge and the crossbeam wedge hole, thereby locking or loosening each layer of beam 100.

[0048] Example 2

[0049] like Figures 3-4 As shown, a composite beam includes two beams 100 and two sets of split wedge assemblies 200. Wedge holes are machined at both ends of the beams 100. The two beams 100 are arranged in a stacked manner. The two sets of split wedge assemblies 200 are fitted into the wedge holes and can lock each layer of beams 100 together. Each split wedge assembly 200 includes an adjusting bolt and two sets of wedge groups 201, namely a first wedge group and a second wedge group. Each wedge group consists of two wedge-shaped sliders, allowing the wedge-shaped sliders in one set to expand or contract along the width direction on both sides (perpendicular to the axial direction of the adjusting bolt).

[0050] In a specific example, the first wedge group is connected to the adjusting bolt, and the first wedge group abuts against the second wedge group so that the second wedge group can expand outward or contract inward under the action of the first wedge group.

[0051] In the above embodiments, the first wedge block group includes a first wedge slider 2011 and a second wedge slider 2012, and the second wedge block group includes a third wedge slider 2013 and a fourth wedge slider 2014. The first wedge slider 2011 and the second wedge slider 2012 are respectively connected to the adjusting bolt so that the first wedge slider 2011 and the second wedge slider 2012 can move relative to each other along the axial direction of the adjusting bolt; the third wedge slider 2013 and the fourth wedge slider 2014 are respectively disposed on both sides of the first wedge slider 2011 and the second wedge slider 2012, and the wedge surfaces on the third wedge slider 2013 and the fourth wedge slider 2014 are in contact with the wedge surfaces on the first wedge slider 2011 and the second wedge slider 2012 so that the third wedge slider 2013 and the fourth wedge slider 2014 can expand or contract outward along both sides.

[0052] It is understandable that during inward contraction, such as Figure 4 As shown, by setting slide rails on the wedge block groups 201 on both sides, the wedge block groups on both sides can be adjusted by adjusting the adjusting bolts to make the wedge block groups on both sides retract inward.

[0053] The first wedge slider 2011 has wedge-shaped surfaces on both sides, and guide grooves or similar features can be machined on these surfaces for guiding sliding. The second wedge slider 2012 also has wedge-shaped surfaces on both sides. The first and second wedge sliders 2011 and 2012 are threadedly connected to an adjusting bolt. A third wedge slider 2013 and a fourth wedge slider 2014 are respectively located on both sides of the adjusting bolt. The third wedge slider 2013 simultaneously contacts the wedge surfaces of the first and second wedge sliders 2011 and 2012 on one side, while the fourth wedge slider 2014 simultaneously contacts the wedge surfaces of the first and second wedge sliders 2011 and 2012 on the other side. It is foreseeable that by rotating the adjusting bolt, the first wedge slider 2011 can move relative to the second wedge slider, thereby allowing the third and fourth wedge sliders 2013 and 2014 to move to lock or release the beams 100 of each layer. Of course, during release, the first wedge slider 2011 and the second wedge slider 2012 move relative to each other to approach each other. At this time, the third wedge slider 2013 and the fourth wedge slider 2014 lose the force in the width direction, which allows the third wedge slider 2013 and the fourth wedge slider 2014 to disengage from the inner wall of the wedge hole, thereby achieving the release operation. Alternatively, the third wedge slider 2013 and the fourth wedge slider 2014 can actively retract under the action of the adjusting bolt by means of guide rails provided on the first wedge slider 2011 and the second wedge slider 2012 in contact with each other, so that the third wedge slider 2013 and the fourth wedge slider 2014 move away from the inner wall of the wedge hole, thereby achieving retraction release.

[0054] The method of setting guide rails on the mating surfaces of the first wedge slider 2011, the third wedge slider 2013, and the fourth wedge slider 2014, and sliding through the guide rails, is a conventional technique in the art, and therefore is not shown in the figure. Similarly, the method of setting guide rails on the mating surfaces of the second wedge slider 2012, the third wedge slider 2013, and the fourth wedge slider 2014 is also not shown in the figure.

[0055] Furthermore, the first wedge slider 2011 is located at the upper end between the third wedge slider 2013 and the fourth wedge slider 2014, and the second wedge slider 2012 is located at the lower end between the third wedge slider 2013 and the fourth wedge slider 2014. Being located at both ends allows the third wedge slider 2013 and the fourth wedge slider 2014 to move as a whole, avoiding partial locking due to localized movement.

[0056] Example 3

[0057] like Figure 5As shown, a composite beam has a single-beam stacked structure that is consistent with the single-beam stacked structure in Example 2, so it will not be described again. Instead, only the differences will be explained. Specifically:

[0058] In this embodiment, the inner wall surface of the wedge hole is machined with a curved structure. Therefore, the outer walls of the third and fourth wedge sliders in the split wedge block assembly 200 are constructed with curved surfaces. The curved surface construction makes the lateral and longitudinal locking strength higher and can have better stability.

[0059] It is understandable that the composite beam structure in the above embodiments can have many applications in engineering. For example, the leaf springs in the suspension system of heavy-duty trucks are usually stacked springs. With the composite beam structure described above, the stiffness and structural strength of such stacked springs can be flexibly adjusted as needed. If a small load capacity and good shock absorption effect are required, the split wedge block assembly 200 can be loosened or the number of single beams can be reduced. If a large load capacity is desired, the split wedge blocks can be locked or the number of single beams can be increased.

[0060] Furthermore, the composite beam described above allows for free replacement of the materials of the individual beams and the combination method of beam 100, making it easy to construct and assemble on-site. This avoids the problem of interference fit between the wedges and individual beams in traditional wedge beams, which makes disassembly and assembly difficult, thus improving flexibility and convenience.

[0061] The present invention also provides a teaching tool suitable for material strain testing. The structure of the teaching tool is a composite beam provided in any of the above embodiments. The composite beam structure can be used as a teaching tool for material strain testing.

[0062] Specifically, strain gauges for measuring strain are provided on the composite beams in the above embodiments.

[0063] It is understandable that the composite beam described in the above embodiments can be applied to experimental teaching as a teaching tool, further demonstrating its superiority. Specifically:

[0064] In traditional bending experiment teaching, it is necessary to prepare single beams, steel-steel stacked beams (two single beams with no fixed connection between them), steel-aluminum stacked beams (two single beams with no fixed connection between them), and steel-steel wedge beams (two beams of the same material fixedly connected with a single wedge block with an interference fit) for experimental teaching. Since they cannot be freely switched and combined, students can only choose one type of beam for experimental testing within the limited class time and analyze the test results. The composite beams in the above embodiments are used for experimental teaching. Students can combine single beams, stacked beams (without fixed connections between beams 100), and complex wedge beams (fixed connections between beams 100), such as steel-steel wedge beams (two single beams), steel-steel-steel-steel wedge beams (three or more single beams), and steel-aluminum-steel-aluminum wedge beams (three or more single beams). Since the combination and wedge preparation practice is very short, students can conduct at least three types of composite beam tests in class, obtain test data with different stiffness and structural strength, greatly expand the teaching content, and provide an efficient and feasible solution for experiments on variable stiffness stacked beams, which facilitates students' understanding of theoretical knowledge.

[0065] Through the above description of the embodiments, those skilled in the art can clearly understand that the present invention, by adjusting the tightness of the bolts, can change the dimensions of the split wedge block assembly 200 in the width direction, achieving an interference fit with the wedge block holes on the beam 100, thereby realizing the locking and unlocking of each layer of beams 100. Furthermore, the wedge-shaped slider optimizes the stress state of the wedge blocks through their contact surfaces, reducing the harmful lateral shear force of the wedge-shaped slider and improving its safety. Furthermore, by adjusting the tightness of the bolts, composite beams can be freely assembled and disassembled on-site, including combinations of different materials, different numbers, and different shapes of beams 100, making assembly quick and more flexible.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite beam comprising at least two layers of beams stacked one on top of the other, said beams being provided with at least one wedge hole for connecting the beams of the respective layers, characterized in that, The wedge assembly further comprises a split wedge assembly installed in the wedge hole; The split wedge assembly comprises an adjusting member and at least one wedge group, and the wedge group comprises a plurality of wedge-shaped sliding blocks; The wedge group comprises a plurality of wedge-shaped sliding blocks, and the adjusting member is connected with the wedge group to enable the wedge-shaped sliding blocks to move relatively along the extension direction of the wedge surface to lock the layers of the beam; The adjusting member comprises an adjusting bolt, the split wedge assembly comprises at least two symmetrically arranged wedge groups, each wedge group comprises a first wedge-shaped sliding block and a second wedge-shaped sliding block, and rotation of the adjusting bolt drives the first wedge-shaped sliding block and the second wedge-shaped sliding block to slide relatively along the wedge surface contacted thereby to generate a radial expansion force to lock the layers of the beam.

2. The composite beam of claim 1, wherein, The wedge group comprises two wedge groups, i.e., a first wedge group and a second wedge group.

3. The composite beam of claim 2, wherein, The first wedge group is connected with the adjusting bolt, and the first wedge group abuts against the second wedge group to enable the first wedge group and the second wedge group to move relatively to expand or contract outwardly under the action of the adjusting bolt.

4. The composite beam of claim 3, wherein, The second wedge group comprises a third wedge-shaped sliding block and a fourth wedge-shaped sliding block. The first wedge-shaped sliding block and the second wedge-shaped sliding block are connected with the adjusting bolt to enable the first wedge-shaped sliding block and the second wedge-shaped sliding block to move relatively along the adjusting bolt in the axial direction. The third wedge-shaped sliding block and the fourth wedge-shaped sliding block are arranged on the two sides of the first wedge-shaped sliding block and the second wedge-shaped sliding block respectively, and the wedge surfaces on the third wedge-shaped sliding block and the fourth wedge-shaped sliding block are in contact with the wedge surfaces on the first wedge-shaped sliding block and the second wedge-shaped sliding block to enable the third wedge-shaped sliding block and the fourth wedge-shaped sliding block to expand or contract outwardly along the two sides.

5. The composite beam of claim 4, wherein, The first wedge-shaped sliding block is located at the upper end between the third wedge-shaped sliding block and the fourth wedge-shaped sliding block, and the second wedge-shaped sliding block is located at the lower end between the third wedge-shaped sliding block and the fourth wedge-shaped sliding block.

6. The composite beam of claim 2, wherein, The beam is a single-layer beam or a multi-layer beam.

7. The composite beam of claim 2, wherein The beam comprises a plurality of wedge holes.

8. A teaching aid suitable for material strain testing, characterized in that, The composite beam comprises the composite beam according to any one of claims 1 to 7.

9. The teaching aid adapted for material strain testing of claim 8, wherein, The composite beam is provided with strain gauges at equal intervals to measure the strain condition.

Images