Axial compression test specimen loading end and assembly method

Abstract

This invention provides a loading end for an axial compression test specimen and an assembly method thereof, comprising: inserting the end of the test specimen into a loading groove, forming a gap between the end of the test specimen and the inner wall of the loading groove; injecting resin into the loading groove to fix the end of the test specimen by the resin wrapping; after the resin has cured, horizontally cutting off the bottom of the loading groove, part of the resin, and part of the end of the test specimen, forming a horizontal machined section on the cut end face of the test specimen, the cut end face of the resin, and the cut bottom surface of the loading groove, which is used for contact and force transmission with the axial compression test loading equipment. This invention ensures effective load transfer during loading by ensuring sufficient contact and force transmission between the machined section and the axial compression test loading equipment. Precise coordination and positioning accuracy between the end of the test specimen and the loading groove is not required, which simplifies assembly positioning requirements, reduces assembly costs, improves test specimen production efficiency, and ensures the accuracy of test loading.

Description

Technical Field

[0001] This invention relates to the field of aerospace manufacturing technology, and in particular to a loading end of an axial compression test piece and its assembly method. Background Technology

[0002] Axial compression testing is a crucial verification item for the strength testing of aerospace structural components and typical structural parts. It is primarily used to test the mechanical properties of test specimens under axial compression. This type of test is of great significance for verifying design calculation methods, examining structural load-bearing capacity and failure mechanisms, and accumulating experience for large-scale structural testing. A large number of structural compression tests are required during aircraft development. Unlike actual installed components, the design of test specimens must consider the connection and transition with the testing equipment, and comprehensively consider factors such as reasonable stress state, ease of mass production, and the acquisition of accurate and effective test data.

[0003] Currently, to interface with testing loading equipment, compression test specimens (such as stringer damage test specimens and stiffened panel test specimens) typically have potted ends in the loading areas at both ends. These potted ends are metal channel-shaped parts, into which the ends of the compression test specimen are embedded and fixed with resin. The test bench transfers the load to the specimen body through these potted ends, thus achieving loading. This design may present the following potential problems for assembly and testing:

[0004] 1) It cannot effectively transmit force. The end face of the compression test piece must be completely fitted with the bottom wall of the metal channel part without any assembly gap. This design has extremely high requirements for the machining accuracy of the bottom wall of the metal channel part and the end face of the compression test piece, as well as the positioning coordination accuracy of the two.

[0005] 2) Accurate loading cannot be guaranteed. Strict requirements exist regarding the perpendicularity tolerance of the compression test specimen's end face to its main axis and the parallelism of the bottom walls of the metal channel components at both ends. Under the influence of potential manufacturing or assembly defects, there may be fitting errors between the end face of the compression test specimen and the bottom wall of the metal channel component. This will result in the test load not being effectively transferred to the compression test specimen, or a deviation in the loading direction, affecting the accuracy of the test data.

[0006] Therefore, it is necessary to propose a loading end and assembly method for axial compression test specimens to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a loading end for an axial compression test specimen and an assembly method thereof, in order to improve the problems of existing potting ends being unable to effectively transmit force and ensure accurate loading.

[0008] This invention provides a method for assembling the loading end of an axial compression test specimen, the assembly method comprising:

[0009] The end of the test piece is inserted into the loading groove, so that a gap is formed between the end of the test piece and the inner wall of the loading groove, wherein the loading groove is hollow inside and the top is open.

[0010] Resin is injected into the loading tank, and the ends of the test piece are fixed by wrapping them with the resin;

[0011] After the resin has cured, the bottom of the loading tank, part of the resin, and part of the end of the test piece are removed by horizontal cutting. The cut end face of the test piece, the cut end face of the resin, and the cut bottom face of the loading tank form a horizontal machined section. The machined section is used to contact and transmit force with the axial compression test loading equipment.

[0012] In one possible embodiment, forming a gap between the end of the test piece and the inner wall of the loading groove includes: leaving a 2mm gap between the end face of the test piece and the inner bottom wall of the loading groove.

[0013] In one possible embodiment, the loading groove includes a base plate and side plates disposed along the edge of the base plate, the base plate having a thickness of 2 mm; during horizontal cutting, a horizontal cut is made at a position 6 mm away from the bottom surface of the loading groove in the height direction.

[0014] In one possible embodiment, forming a gap between the end of the test piece and the inner wall of the loading groove further includes: leaving a gap of at least 10 mm between the side of the end of the test piece and the inner wall of the loading groove.

[0015] In one possible embodiment, the parallelism of the machined section is no greater than 0.05 mm.

[0016] In one possible embodiment, the perpendicularity tolerance between the machined section and the spindle direction of the test piece is no greater than 0.1 mm.

[0017] The present invention also provides a loading end for an axial compression test specimen, the loading end comprising: a cut side plate and resin; the cut side plate is cut from a loading groove, the loading groove being hollow inside and open at the top, the end of the test specimen being inserted into the loading groove, and a gap being formed between the end of the test specimen and the inner wall of the loading groove; the resin is cured and formed in the loading groove, and the end of the test specimen is fixed by the resin; the cut side plate is obtained by horizontal cutting to remove the bottom of the loading groove, part of the resin, and part of the end of the test specimen, the cut end face of the test specimen, the cut end face of the resin, and the bottom surface of the side plate forming a horizontal machined section, the machined section being used for contacting and transmitting force with an axial compression test loading device.

[0018] In one possible embodiment, the loading groove includes a base plate and a side plate before cutting. The side plate before cutting is disposed along the edge of the base plate. The base plate has a thickness of 2 mm. The distance between the end face of the test piece and the base plate is 2 mm. The cutting length of the loading groove from the bottom surface of the loading groove in the height direction is 6 mm.

[0019] In one possible embodiment, the distance between the side of the end of the test piece and the inner wall of the loading groove is at least 10 mm.

[0020] In one possible embodiment, the parallelism of the machined section is no greater than 0.05 mm; the perpendicularity tolerance between the machined section and the main axis direction of the test piece is no greater than 0.1 mm.

[0021] The beneficial effects of this invention are as follows: During assembly, the end of the test piece is inserted into the loading groove, creating a gap between the end of the test piece and the inner wall of the loading groove. A horizontal machined section is formed by cutting, and this machined section fully contacts the axial compression test loading device to transmit force, ensuring effective load transfer during loading. Furthermore, since the end of the test piece does not need to be in contact with the inner wall of the loading groove, precise coordination of positioning accuracy is not required, which simplifies assembly positioning requirements, reduces assembly costs, improves test piece production efficiency, and ensures the accuracy of test loading. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the assembly method of the loading end of the axial compression test specimen according to the present invention.

[0023] Figure 2 This is a diagram showing the state of the axial compression test specimen after resin injection in the assembly method of the loading end of the present invention.

[0024] Figure 3 for Figure 2 Cross-sectional view along the AA direction.

[0025] Figure 4 This is a diagram showing the state after cutting in the axial compression test specimen loading end assembly method of the present invention.

[0026] Figure 5 for Figure 4 Cross-sectional view along the BB direction.

[0027] Figure 6 These are images showing the loading groove before and after cutting in the axial compression test specimen loading end assembly method of the present invention.

[0028] Symbol explanation: Test piece 200;

[0029] Loading tank 300; bottom plate 310; side plate 320;

[0030] Resin 400;

[0031] Machined section 500. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Precise matching between the potting tip and the test specimen body is essential to ensure effective force transfer. Any gaps or mismatches between the two may result in ineffective load transfer, affecting the accuracy and reliability of the test results.

[0034] To address the problems existing in the above-mentioned technologies, embodiments of the present invention provide a method for assembling the loading end of an axial compression test specimen. Figure 1 This is a flowchart illustrating the assembly method of the loading end of the axial compression test specimen according to the present invention. See [link / reference]. Figure 1 The assembly method includes:

[0035] S101: Figure 2 This is a diagram showing the state of the axial compression test specimen after resin injection in the assembly method of the loading end of the present invention. (See attached diagram) Figure 2 The end of the test specimen 200 is inserted into the loading groove 300, forming a gap between the end of the test specimen 200 and the inner wall of the loading groove 300. The loading groove 300 is hollow inside and open at the top. Preferably, the loading groove 300 has a square groove structure, and the groove size is defined to accommodate the test specimen 200.

[0036] S102: Figure 3 for Figure 2 See the cross-sectional view along the AA direction. Figure 3 Resin 400 is injected into the loading tank 300, and the end of the test piece 200 is wrapped and fixed by the resin 400.

[0037] S103: Figure 4 This is a diagram showing the state after cutting in the axial compression test specimen loading end assembly method of the present invention. Figure 5 for Figure 4 See the cross-sectional view in the middle BB direction. Figure 4 and Figure 5After the resin 400 has cured, the bottom of the loading tank 300, part of the resin 400, and part of the end of the test piece 200 are removed by horizontal cutting. The cut end face of the test piece 200, the cut end face of the resin 400, and the cut bottom face of the loading tank 300 form a horizontal machined section 500. The machined section 500 is used to contact and transmit force with the axial compression test loading equipment.

[0038] In this embodiment, the loading groove 300 is used to accommodate the end of the test specimen 200 and the resin 400. The resin 400 is used to fix the end of the test specimen 200 within the loading groove 300, ensuring stable load transfer during the compression test. By machining, the bottom of the loading groove 300, a portion of the resin 400, and a portion of the end of the test specimen 200 are removed to obtain a horizontal machined section 500. The horizontal machined section 500 can fully contact the axial compression test loading device, allowing the test load to be effectively transferred to the test specimen 200, thereby ensuring the accuracy and reliability of the test results. The end of the test piece 200 does not require high-precision coordination and positioning with the loading groove 300, nor does it require high-precision machining of the test piece 200 and the loading groove 300, which reduces manufacturing costs. Moreover, the assembly process is simple, reduces dependence on technical and operational precision, improves assembly flexibility and fault tolerance, and reduces assembly costs. The fast and simple assembly process improves the production efficiency of the test piece 200.

[0039] In a preferred embodiment, see [link to previous document]. Figure 3 To create a gap between the end of the test piece 200 and the inner wall of the loading groove 300, the following measures are taken: a 2mm gap is reserved between the end face of the test piece 200 and the inner bottom wall of the loading groove 300.

[0040] In one specific embodiment, see Figure 3 The loading groove 300 includes a base plate 310 and a side plate 320 disposed along the edge of the base plate 310. The base plate 310 has a thickness of 2mm. During horizontal cutting, a horizontal cut is made at a position 6mm away from the bottom surface of the loading groove 300 in the height direction.

[0041] In a preferred embodiment, see [link to previous document]. Figure 3 The method further includes creating a gap between the end of the test piece 200 and the inner wall of the loading groove 300, and also includes leaving a gap of at least 10 mm between the side of the end of the test piece 200 and the inner side wall of the loading groove 300.

[0042] A gap is left between the end of the test piece 200 and the inner wall of the loading groove 300 to ensure the fluidity of the resin 400 within the loading groove 300. This allows the resin 400 to fill the loading groove 300 and encapsulate the end of the test piece 200. After the resin 400 cures, the end of the test piece 200 is fixed within the loading groove 300. The bottom plate 310 and part of the side plates 320 of the loading groove 300, along with the partially cured resin 400 and the end area of ​​the test piece 200, are removed by machining. Considering the bottom plate 310 thickness is 2mm and the reserved gap is 2mm, the cutting depth should ensure the removal of all resin 400 from the end face of the test piece 200 and the gap, which is 6mm. This cutting design also reduces the precision requirements for the machining of the test piece 200 and the loading groove 300.

[0043] In one specific embodiment, the parallelism of the machined section 500 is no greater than 0.05 mm.

[0044] In one specific embodiment, the perpendicularity tolerance between the machined section 500 and the spindle direction of the test piece 200 is no greater than 0.1 mm.

[0045] During cutting, the parallelism and perpendicularity of the machined section 500 are controlled to ensure that the load can be accurately and evenly transferred to the test piece 200 during the compression test, thereby ensuring the accuracy and reliability of the axial compression test. Compared with the machining accuracy of the bottom wall of the metal groove part and the end face of the compression test piece 200 and the positioning coordination accuracy of the two in the prior art, the cutting accuracy is easier to control.

[0046] In addition, the present invention also provides a loading end for an axial compression test specimen, see [link to relevant documentation]. Figure 4 The loading end includes a cut side plate 320 and resin 400. The cut side plate 320 is cut from a loading groove 300, which is hollow inside and open at the top. The end of the test piece 200 is inserted into the loading groove 300, and a gap is formed between the end of the test piece 200 and the inner wall of the loading groove 300. The resin 400 is cured and formed inside the loading groove 300, and the end of the test piece 200 is fixed by the resin 400. The cut side plate 320 is obtained by horizontally cutting off the bottom of the loading groove 300, part of the resin 400, and part of the end of the test piece 200. The cut end face of the test piece 200, the cut end face of the resin 400, and the bottom surface of the side plate 320 form a horizontal machined section 500, which is used to contact and transmit force with the axial compression test loading device.

[0047] In a preferred embodiment, see [link to previous document]. Figure 3The loading groove 300 includes a base plate 310 and a side plate 320 before cutting. The side plate 320 before cutting is arranged along the edge of the base plate 310. The base plate 310 has a thickness of 2mm. The distance between the end face of the test piece 200 and the base plate 310 is 2mm. The cutting length of the loading groove 300 from the bottom surface of the loading groove 300 in the height direction is 6mm.

[0048] In one specific embodiment, see Figure 3 The distance between the side of the end of the test piece 200 and the inner wall of the loading groove 300 is at least 10 mm.

[0049] In one specific embodiment, the parallelism of the machined section 500 is no greater than 0.05 mm, and the perpendicularity tolerance between the machined section 500 and the main axis direction of the test piece 200 is no greater than 0.1 mm.

[0050] Figure 6 The images shown are of the loading groove body before and after cutting in the axial compression test specimen loading end assembly method of this invention. (See attached image.) Figure 6 Before assembly, to facilitate the injection of resin 400, the loading tank 300 has a bottom surface. The dimensional accuracy of the loading tank 300 and the end face of the test piece 200 can be controlled according to general tolerances, with no special requirements. After assembly, the bottom surface of the loading tank 300 is cut off, resulting in a clamp-type configuration with annular side plates 320.

[0051] Compared to existing technologies where compression test specimens and metal grooved parts may suffer from problems due to dimensional tolerances and assembly errors, the axial compression test specimen loading end and assembly method of this invention improves these potential problems through mechanical cutting. Specifically, the bottom of the loading groove 300, part of the resin 400, and part of the end of the test specimen 200 are removed by machining to obtain a horizontal machined section 500. This machined section 500 ensures sufficient contact and force transmission with the axial compression test loading device, guaranteeing effective load transfer during loading. Since strict dimensional tolerance requirements are not required, simpler manufacturing methods can be used, reducing complex and precise machining steps. The simplified manufacturing process leads to cost reduction, making mass production more economical and efficient. Reduced reliance on dimensional accuracy speeds up production and increases output. Reserved clearances make the assembly process more forgiving, reducing the risk of assembly errors. No complex alignment and positioning steps are required, resulting in faster assembly with less manual operation. This solution integrates ease of manufacturing and assembly with accuracy of testing, balancing cost, efficiency, and accuracy. It facilitates efficient, mass production of test pieces 200 and ensures accurate loading of the test conditions.

[0052] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways. Unless otherwise defined, the technical or scientific terms used herein should be understood in their ordinary sense by one of ordinary skill in the art to which this invention pertains. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

Claims

1. A method for assembling the loading end of an axial compression test specimen, characterized in that, The assembly method includes: The end of the test piece is inserted into the loading groove, so that a gap is formed between the end of the test piece and the inner wall of the loading groove, wherein the loading groove is hollow inside and the top is open. Resin is injected into the loading tank, and the ends of the test piece are fixed by wrapping them with the resin; After the resin has cured, the bottom of the loading tank, part of the resin, and part of the end of the test piece are removed by horizontal cutting. The cut end face of the test piece, the cut end face of the resin, and the cut bottom face of the loading tank form a horizontal machined section. The machined section is used to contact and transmit force with the axial compression test loading equipment. The parallelism of the machined section is not greater than 0.05 mm.

2. The method for assembling the loading end of an axial compression test specimen according to claim 1, characterized in that, To create a gap between the end of the test piece and the inner wall of the loading groove, including: A 2mm gap is reserved between the end face of the test piece and the inner bottom wall of the loading groove.

3. The method for assembling the loading end of an axial compression test specimen according to claim 2, characterized in that, The loading groove includes a base plate and side plates disposed along the edge of the base plate, the base plate having a thickness of 2mm; During horizontal cutting, a horizontal cut is made at a position 6 mm away from the bottom surface of the loading groove in the height direction of the loading groove.

4. The method for assembling the loading end of an axial compression test specimen according to claim 2, characterized in that, To create a gap between the end of the test piece and the inner wall of the loading groove, the method further includes: A gap of at least 10 mm is reserved between the side of the end of the test piece and the inner wall of the loading groove.

5. The method for assembling the loading end of an axial compression test specimen according to claim 1, characterized in that, The perpendicularity tolerance between the machined section and the main axis of the test piece is no greater than 0.1 mm.

6. A loading end for an axial compression test specimen, characterized in that, The loading end includes: a cut side plate and resin; The cut side plate is cut from a loading groove, which is hollow inside and open at the top. The end of the test piece is inserted into the loading groove, and a gap is formed between the end of the test piece and the inner wall of the loading groove. The resin is cured and formed in the loading groove, and the ends of the test piece are fixed by the resin wrapping. The bottom of the loading tank, part of the resin, and part of the end of the test piece are removed by horizontal cutting to obtain the cut side plate. The cut end face of the test piece, the cut end face of the resin, and the bottom surface of the side plate form a horizontal machined section. The machined section is used to contact and transmit force with the axial compression test loading equipment. The parallelism of the machined section is not greater than 0.05 mm.

7. The loading end of the axial compression test specimen according to claim 6, characterized in that, The loading groove includes a base plate and a side plate before cutting. The side plate before cutting is set along the edge of the base plate. The base plate has a thickness of 2mm. The distance between the end face of the test piece and the base plate is 2mm. The cutting length of the loading groove from its bottom surface in the height direction is 6mm.

8. The loading end of the axial compression test specimen according to claim 6, characterized in that, The distance between the side of the end of the test piece and the inner wall of the loading groove is at least 10 mm.

9. The loading end of the axial compression test specimen according to claim 6, characterized in that, The perpendicularity tolerance between the machined section and the main axis of the test piece is no greater than 0.1 mm.

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