Aircraft composite laminate single-punch double-shear test structure

Abstract

This application belongs to the technical field of single-nail double-shear test for aircraft composite laminates, specifically relating to a single-nail double-shear test structure for aircraft composite laminates. The design utilizes two bushings to transfer load between the tension plate and the composite laminate. When the bushing deforms or the loading hole diameter changes, only a bushing with the corresponding inner diameter needs to be replaced, which is convenient and quick, ensuring the loading effect on the composite laminate. Furthermore, set screws and pads are provided on the two tension plates, allowing for easy adjustment by turning the set screws to ensure the distance between the two tension plates connected to the testing machine clamps matches the thickness of the composite laminate, thereby reducing the dispersion of test results.

Description

Technical Field

[0001] This application belongs to the technical field of single-nail double-shear test of aircraft composite laminates, specifically relating to a single-nail double-shear test structure for aircraft composite laminates. Background Technology

[0002] Aircraft use a large number of composite laminates, which need to be verified by extrusion tests to ensure the safety of the connection structure. Among them, the single-nail double-shear test is an important category of extrusion test.

[0003] Currently, when conducting single-nail double-shear tests on composite laminates, the design involves connecting one end of the composite laminate to a clamp of the testing machine, machining a loading hole at the other end (the hole diameter is determined according to aircraft design requirements), and designing two pull plates with one end located on either side of one end of the composite laminate. Load transfer holes of corresponding diameter are machined on these pull plates, and a pin passes through the loading hole and its load transfer hole to connect the composite laminate and the pull plates. A shim of appropriate thickness is placed between the other ends of the two pull plates, connecting to another clamp of the testing machine for load application. This technical solution has the following drawbacks:

[0004] 1) The diameter of the loading holes on the two pull plates needs to be consistent with the diameter of the loading holes on the composite laminate. In practice, after multiple loading tests, the loading holes on the two pull plates will undergo large deformation, making it difficult to guarantee the loading effect on the composite laminate. Furthermore, it is no longer applicable when the diameter of the loading holes on the composite laminate changes.

[0005] 2) The thickness of the pad needs to be consistent with the thickness of the composite laminate. In practice, it is difficult for different batches of composite laminates to be completely consistent, and there may be cases where the pad thickness is too large or too small, which increases the dispersion of test results.

[0006] This application is made in view of the aforementioned technical deficiencies.

[0007] It should be noted that the above background information is only used to assist in understanding the inventive concept and technical solution of this application, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0008] The purpose of this application is to provide a single-nail double-shear test structure for aircraft composite laminates to overcome or mitigate at least one of the known technical defects.

[0009] The technical solution of this application is:

[0010] A single-nail double-shear test structure for aircraft composite laminates includes:

[0011] The composite laminate is connected at one end to a clamp of the testing machine and has a loading hole at the other end.

[0012] Two pull plates, one end of which is located on both sides of the end of the composite laminate with loading holes, and this end has load transfer holes; the other end of the two pull plates has multiple set screw holes, which are connected to another clamp of the testing machine;

[0013] Two bushings are screwed into two load transfer holes, with the inner diameter matching the diameter of the loading hole.

[0014] The loading pin passes through the loading hole and is positioned within the inner holes of the two bushings.

[0015] Tighten the nuts, screwing them onto the loading pin, so that the two bushings clamp the end of the composite laminate with the loading hole;

[0016] Two pads are set between the ends of the two pull plates with set screw holes, and the sum of their thicknesses is less than the thickness of the composite laminate. They have multiple positioning holes.

[0017] Two sets of set screws are screwed into the set screw holes of two pull plates and pressed against the positioning holes on two pads. The distance between the ends of the two pull plates with set screw holes is adjusted to match the thickness of the composite laminate.

[0018] According to at least one embodiment of this application, in the above-mentioned aircraft composite laminate single-nail double-shear test structure, the inner side of one end of the two pull plates with top screw holes has a positioning groove.

[0019] The two pads are secured in the two positioning slots.

[0020] According to at least one embodiment of this application, in the above-described aircraft composite laminate single-nail double-shear test structure, the outer ends of the two bushings have outward flanges.

[0021] According to at least one embodiment of this application, in the above-described aircraft composite laminate single-nail double-shear test structure, the two outward flanges are hexagonal.

[0022] According to at least one embodiment of this application, in the above-mentioned aircraft composite laminate single-nail double-shear test structure, the two sets of set screws are fully threaded internal hexagonal screws.

[0023] This application has at least the following beneficial technical effects:

[0024] A single-nail double-shear test structure for aircraft composite laminates is provided. The design utilizes two bushings to transfer load between the tension plate and the composite laminate. When the bushing deforms or the loading hole diameter changes, only a bushing with the corresponding inner diameter needs to be replaced, which is convenient and quick, and can ensure the loading effect on the composite laminate. In addition, set screws and pads are provided on the two tension plates, which can be easily adjusted by turning the set screws to make the distance between the two tension plates connected to the test machine clamps consistent with the thickness of the composite laminate, thereby reducing the dispersion of test results. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the single-nail double-shear test structure of the aircraft composite laminate provided in the embodiments of this application;

[0026] Figure 2 This is a partial cross-sectional view of the single-nail double-shear test structure of the aircraft composite laminate provided in the embodiments of this application;

[0027] Figure 3 This is another partial cross-sectional view of the single-nail double-shear test structure of the aircraft composite laminate provided in the embodiments of this application;

[0028] in:

[0029] 1-Composite laminate; 2-Pulley plate; 3-Bushing; 4-Loading pin; 5-Fasting nut; 6-Washer plate; 7-Top screw.

[0030] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual size of the product. Furthermore, the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. Detailed Implementation

[0031] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0032] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used only for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0033] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0034] The following is in conjunction with the appendix Figures 1 to 3 This application will be described in further detail.

[0035] A single-nail double-shear test structure for aircraft composite laminates includes:

[0036] The composite laminate 1 is connected to a clamp of the testing machine at one end and has a loading hole at the other end. The diameter of the loading hole is determined according to the aircraft design requirements.

[0037] Two pull plates 2, one end of which is located on both sides of the end of the composite laminate 1 with the loading hole, and the end has the load transfer hole; the other end of the two pull plates 2 has multiple set screw holes, which are connected to another clamp of the testing machine;

[0038] Two bushings 3 are screwed into two load transfer holes, and their inner diameter is the same as the diameter of the loading hole.

[0039] Loading pin 4 passes through the loading hole and is set in the inner hole of the two bushings 3;

[0040] Tighten the nut 5, which is screwed onto the loading pin 4, so that the two bushings 3 clamp the end of the composite laminate 1 with the loading hole;

[0041] Two pads 6 are set between the ends of the two pull plates 2 with top screw holes. The sum of their thicknesses is less than the thickness of the composite laminate 1. That is, the two pads 6 are designed to have a smaller thickness relative to the composite laminate 1, and have multiple positioning holes.

[0042] Two sets of set screws 7 are screwed into the set screw holes of two pull plates 2 and pressed against the positioning holes on two pads 6. The distance between the ends of the two pull plates 2 with set screw holes is adjusted to be consistent with the thickness of the composite material laminate 1.

[0043] Regarding the single-nail double-shear test structure for aircraft composite laminates disclosed in the above embodiments, those skilled in the art will understand that its design utilizes two bushings 3 to transfer load between the pull plate 2 and the composite laminate 1. When the bushing 3 deforms or the loading hole diameter changes, it is only necessary to replace the bushing 3 with the corresponding inner diameter, which is convenient and quick and can ensure the loading effect on the composite laminate 1. In addition, the two pull plates 2 are provided with set screws 7 that cooperate with the pads 6. The distance between the two pull plates 2 and the end of the test machine clamp is easily adjusted by turning the set screws 7 to be consistent with the thickness of the composite laminate 1, thereby reducing the dispersion of the test results.

[0044] For the single-nail double-shear test structure of the aircraft composite laminate disclosed in the above embodiments, those skilled in the art will understand that its design uses two bushings 3 to clamp the end of the composite laminate 1 with the loading hole, which has a small contact area and can avoid large-area contact between the composite laminate 1 and the pull plate 2, so as to reduce the influence of friction on the test results.

[0045] For the single-nail double-shear test structure of the aircraft composite laminate disclosed in the above embodiments, those skilled in the art will understand that it is designed with two pads 6 between the two pull plates 2, and the two pads 6 can move relative to each other to avoid over-fitting with the two sets of set screws 7 screwed on the pull plates 2.

[0046] In some optional embodiments, in the above-described aircraft composite laminate single-nail double-shear test structure, the inner side of one end of the two pull plates 2 with the top screw hole has a positioning groove.

[0047] The two pads are secured in the two positioning slots.

[0048] In some alternative embodiments, in the above-described aircraft composite laminate single-nail double-shear test structure, the outer ends of the two bushings 3 have outward flanges, which can be placed between the head of the loading pin 4, the fastening nut 5 and the pull plate 2.

[0049] In some alternative embodiments, in the above-described single-nail double-shear test structure of the aircraft composite laminate, the two outward flanges are hexagonal to facilitate twisting.

[0050] In some alternative embodiments, in the above-described single-nail double-shear test structure for aircraft composite laminates, the two sets of set screws 7 are fully threaded internal hexagonal screws.

[0051] The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0052] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A single-nail double-shear test structure for aircraft composite laminates, characterized in that, include: The composite laminate (1) has one end connected to a clamp of the testing machine and the other end has a loading hole; Two pull plates (2) are located on both sides of the end of the composite laminate (1) with loading holes, which has load transfer holes; the other end of the two pull plates (2) has multiple set screw holes and is connected to another clamp of the testing machine. Two bushings (3) are screwed into two load transfer holes, with the inner diameter matching the diameter of the loading hole; The loading pin (4) passes through the loading hole and the inner holes of the two bushings (3); Tighten the nut (5) and screw it onto the loading pin (4) so ​​that the two bushings (3) clamp the end of the composite laminate (1) with the loading hole; Two pads (6) are set between the ends of the two pull plates (2) with set screw holes, and the sum of their thicknesses is less than the thickness of the composite laminate (1), and they have multiple positioning holes. Two sets of set screws (7) are screwed into the set screw holes of two pull plates (2) and pressed into the positioning holes on two pads (6). The distance between the ends of the two pull plates (2) with set screw holes is adjusted to be consistent with the thickness of the composite laminate (1).

2. The single-nail double-shear test structure for aircraft composite laminates according to claim 1, characterized in that, The inner side of one end of the two pull plates (2) with the set screw hole has a positioning groove; Two pads (6) are secured in two positioning slots.

3. The single-nail double-shear test structure for aircraft composite laminates according to claim 1, characterized in that, The outer ends of the two bushings (3) have outward flanges.

4. The single-nail double-shear test structure for aircraft composite laminates according to claim 3, characterized in that, The two outward-facing flanges are in the shape of a regular hexagon.

5. The single-nail double-shear test structure for aircraft composite laminates according to claim 1, characterized in that, Both sets of set screws (7) are fully threaded internal hexagonal screws.

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