Processing device and method for fracture toughness specimen of aviation non-metallic material

Abstract

The present invention relates to a processing device and method for fracture toughness specimens of aviation non-metallic materials, comprising a special slotting tool, a special Y-shaped saw 1, and a clamping and positioning fixture. The clamping and positioning fixture includes a reference positioning U-shaped block 6, each vertical side of which is machined with a Y-shaped groove 9 having the same structure as the special Y-shaped saw blade 4. The Y-shaped groove 9 includes an upper rectangular groove, a middle V-shaped groove, and vertically distributed cracks. A specimen 10 is sandwiched between the two vertical sides of the reference positioning U-shaped block 6. The specimen rests on the horizontal side of the reference positioning U-shaped block 6. The special Y-shaped saw passes through the Y-shaped groove 9 and machines prefabricated cracks 12 on the specimen 10 along the vertically distributed cracks. The present invention is very suitable for batch processing of prefabricated cracks. The processed cracks have high dimensional consistency and stable quality, which is of great significance for accurately characterizing the test results of the mechanical properties of the specimens.

Description

Technical Field

[0001] The invention relates to the field of mechanical processing of aviation material mechanical property samples, and in particular to a processing device and method for aviation non-metallic material fracture toughness samples. Background Art

[0002] Fracture toughness reflects a material's ability to resist crack propagation, i.e., brittle fracture. It is a comprehensive reflection of a material's strength and toughness and an important mechanical property indicator. As the carrier for mechanical property test data, the quality of specimen processing can affect the accuracy of the test data. While the notch of thin fracture toughness specimens can be created simultaneously with the outer shape on a machining center, the pre-crack size is too small to be completed simultaneously on the machining center, requiring re-alignment and positioning. This reduces processing efficiency and can easily cause the pre-crack centerline to be misaligned with the notch centerline, compromising specimen processing quality. For thick fracture toughness specimens, the small notch size limits the size of the milling cutter used, and the cutter length is limited to at least 1 / 2 the specimen thickness, making it impossible to create the notch on a machining center. While wire cutting is commonly used to create notches and pre-cracks in metallic materials, non-metallic materials are non-conductive and cannot be processed using wire cutting. While some existing patents can process pre-cracks in non-metallic materials, they cannot simultaneously create V-shaped notches, resulting in low processing efficiency. To address this issue, the present invention provides a method for processing notches and pre-cracks in fracture toughness specimens of non-metallic materials for aviation. Summary of the Invention

[0003] The purpose of the present invention is to provide a processing device and method for fracture toughness specimens of aviation non-metallic materials, which is used to solve a processing method for notches and prefabricated cracks in fracture toughness specimens of aviation non-metallic materials, process fracture toughness specimens with high quality and high efficiency, and ensure that the test data of the mechanical properties of the materials are true and reliable.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0005] A processing device for a fracture toughness specimen of an aviation non-metallic material comprises a special slotting tool, a special Y-shaped saw (1), and a clamping and positioning fixture, wherein the special slotting tool is used to process a notch (11) on a specimen (10); the special Y-shaped saw (1) comprises a handle (2) and a Y-shaped saw blade (4); the clamping and positioning fixture comprises a reference positioning U-shaped block (6), and the two vertical sides of the reference positioning U-shaped block (6) are respectively processed with Y-shaped grooves (9) having the same structure as the special Y-shaped saw blade (4), the Y-shaped grooves (9) comprising an upper rectangular groove, a middle V-shaped groove, and vertically distributed cracks; a specimen (10) is sandwiched between the two vertical sides of the reference positioning U-shaped block (6), and the specimen rests on the horizontal side of the reference positioning U-shaped block (6); the special Y-shaped saw passes through the Y-shaped groove (9) and processes a notch (11) and a prefabricated crack (12) on the specimen (10) along the vertically distributed cracks.

[0006] Preferably, the special grooving tool includes a grooving tool (13), a stepped shaft (14), a gasket (15), and a locking nut (16); the large end of the stepped shaft (14) is clamped on the tool handle of a vertical machining center / milling machine; the width and angles of the grooving tool (13) are consistent with the size of the notch (11) on the sample (10).

[0007] Preferably, the samples (10) are fixed vertically on a vertical machining center / milling machine in groups of 3 to 20 pieces, and protective pieces of the same material are added on both sides of the samples (10) to prevent the samples (10) from being chipped and pinched during machining.

[0008] Preferably, the notch (11) is composed of a rectangular and a V-shaped part. The vertical machining center / milling machine drives a special slotting tool to rotate at a constant speed and feed horizontally to process the notch (11) in layers. The tool speed is 400rpm to 1000rpm, the cutting feed is 10mm / s to 30mm / s, and the layer cutting depth is 0.2mm to 0.5mm.

[0009] Preferably, the Y-shaped saw (1) further comprises a clamping screw (3), the handle (2) is processed with a hole groove in the center and a threaded hole in the side, the saw handle of the special Y-shaped saw blade (4) is inserted into the hole groove of the handle (2), and the clamping bolt (3) is screwed into the threaded hole on the side of the handle (2) to fasten the Y-shaped saw blade (3) and the handle (2) together.

[0010] Preferably, a threaded hole is processed on the large surface of one side of the reference positioning U-shaped block (6), and a through Y-shaped groove (9) is processed in a direction perpendicular to the large surface. The Y-shaped groove (9) has the same structure as the Y-shaped saw blade (4), and extends above the Y-shaped groove (9). The extension length is more than 2 mm greater than the depth of the prefabricated crack (12), which is convenient for positioning the starting processing position of the Y-shaped saw (1) in the length direction and has a guiding effect. The length of the crack below the Y-shaped groove (9) is greater than the size of the same structure on the Y-shaped saw blade (4), avoiding interference when processing the prefabricated crack (12) on the fracture toughness specimen (10).

[0011] Preferably, the horizontal side of the reference positioning U-shaped block (6) is an end face positioning block (5), which is connected to the two vertical sides of the reference positioning U-shaped block (6) by screws to locate the position of the notch (11) in length.

[0012] Preferably, the two vertical inner side surfaces of the reference positioning U-shaped block (6) serve as reference positioning surfaces for the sample (10), ensuring that the large surface of the sample (10) to be processed is perpendicular to the Y-shaped groove (9), and the V-shaped portion at the bottom of the notch (11) is at the same height as the V-shaped groove in the middle of the Y-shaped groove (9).

[0013] Preferably, the Y-shaped groove (9) is consistent in size with the notch (11) and prefabricated crack (12) of the same structure on the sample (10), limiting the processing depth of the notch (11) and prefabricated crack (12) on the fracture toughness sample (10).

[0014] Preferably, the clamping and positioning fixture also includes a disc bolt (7) and an L-shaped gasket (8), wherein the L-shaped gasket (8) is placed on the large surface of the sample (10), and the disc bolt (7) passes through the threaded hole on the large surface of the reference positioning U-shaped block (6) to press the L-shaped gasket (8) to fix the sample (10), and the L-shaped gasket (8) prevents the surface of the sample (10) from being scratched by the rotation and compression of the disc bolt (7).

[0015] Preferably, the sample (10) is a rectangular sample, one side of which needs to be processed with a notch (11) and a prefabricated crack (12), the shape of the notch (11) includes but is not limited to a V-shape, the maximum width of the notch is 2mm to 4mm, the notch depth is 2mm to 8mm, and the material includes organic glass, carbon fiber composite and non-metallic materials for aviation.

[0016] A method for processing prefabricated cracks in aviation non-metallic materials comprises selecting any of the above-described processing devices, pre-installing the special Y-shaped saw blade (4) in the Y-shaped groove (9), controlling the Y-shaped saw (1) to reciprocate in the Y-shaped groove (9) and applying downward force to the Y-shaped saw (1) until the middle V-shaped portion of the special Y-shaped saw blade (4) contacts the V-shaped portion of the Y-shaped groove (9), and removing the special Y-shaped saw blade (4) upward to achieve processing of the prefabricated crack (12) on the fracture toughness specimen (10).

[0017] Preferably, the special Y-shaped saw blade (4) is similar in shape to the notch (11) and the prefabricated crack (12) on the fracture toughness specimen (10), with the upper portion being rectangular, the middle being V-shaped, and the lower portion being a vertically distributed thin plate, and the saw teeth being located on the vertically distributed thin plate in the lower portion. The size of the special Y-shaped saw blade (4) is substantially similar to the notch (11) and the prefabricated crack (12) on the fracture toughness specimen (10), with the only difference being that the overall width is 0.01 mm to 0.02 mm smaller than the width of the notch (11) and the prefabricated crack (12).

[0018] The present invention has the following advantages:

[0019] 1. The present invention has a simple structure and is easy to operate. The notches are processed in groups with high efficiency. The size of the prefabricated cracks is ensured by a special Y-shaped saw blade. No measurement or control is required during the processing, and the processing efficiency is high.

[0020] 2. The present invention is very suitable for batch processing of prefabricated cracks. The processed cracks have high consistency in size and stable quality, which is of great significance for the accurate characterization of the test results of the mechanical properties of the specimens.

[0021] 3. The present invention fills the technical gap in the Y-groove processing of fracture toughness specimens. The specimen surface has no edge collapse and the qualified rate is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the fracture toughness specimen after processing according to the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the patented Y-shaped saw of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the patented clamping and positioning fixture of the present invention;

[0025] Figure 4 This is a schematic diagram of the overall structure of the patent of this invention;

[0026] Figure 5 This is a schematic diagram of the structure of the patented special grooving tool of this invention.

[0027] In the figure: 1-Y-shaped saw, 2-handle, 3-pressing screw, 4-Y-shaped saw blade, 5-end face positioning block, 6-reference positioning U-shaped block, 7-dish bolt, 8-L-shaped gasket, 9-Y-shaped groove, 10-sample, 11-notch, 12-prefabricated crack, 13-grooving knife, 14-step shaft, 15-gasket, 16-locking nut DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application.

[0029] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0030] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0031] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0032] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0033] Example

[0034] The structural principle and working principle of the patent of the present invention are further described below with reference to the accompanying drawings, and the specific implementation methods are used to further describe the present invention, but the scope of protection of this patent is not limited to the implementation methods.

[0035] like Figure 1 As shown, the fracture task specimen structure is rectangular, with a notch and a prefabricated crack processed on one long side. The notch consists of a rectangular part and a V-shaped part. The material is aviation-grade organic glass.

[0036] like Figure 2 As shown, the Y-shaped saw used in this method for processing fracture toughness specimens of aviation non-metallic materials consists of a handle 2, a clamping screw 3, and a special Y-shaped saw blade 4. The handle 1 has a central slot and a threaded hole on the side. The handle of the Y-shaped saw blade 4 is inserted into the slot of the handle 2. The clamping screw 3 in the threaded hole on the side of the handle 2 is tightened to fasten the Y-shaped saw blade 3 to the handle 2. The special Y-shaped saw blade 4 has the same shape as the notch 11 and prefabricated crack 12 on the fracture toughness specimen 10, with a rectangular upper portion, a V-shaped middle portion, and a vertically distributed crack at the lower portion. The saw teeth are located in the vertically distributed crack at the lower portion, and the saw tooth width is 0.01mm to 0.02mm smaller than the prefabricated crack width. The width of the rectangular portion of the upper portion is 0.02mm to 0.03mm narrower than the width of the opening of the notch 11, and the V-shaped portion in the middle is the same size as the V-shaped portion of the notch 11.

[0037] like Figure 3As shown, the clamping fixture used in this method for processing fracture toughness specimens of aviation non-metallic materials includes an end face positioning block 5, a reference positioning U-shaped block 6, a disc bolt 7, and an L-shaped gasket 8. A Y-shaped groove 9, identical in structure to the custom Y-shaped saw blade 4, is machined above the reference positioning U-shaped block 6. A threaded hole is machined into one end face of the reference positioning U-shaped block 6, securing the end face positioning block 5 and used to position the fracture toughness specimen 10 in the longitudinal direction. A threaded hole is machined into the large surface of one side of the reference positioning U-shaped block 6, and a through Y-shaped groove 9 is machined perpendicular to the large surface. The Y-shaped groove 9 has the same structure as the custom Y-shaped saw blade 4 and extends upward. The extended length is at least 2 mm greater than the combined depth of the notch 11 and the prefabricated crack 12, facilitating the positioning of the Y-shaped saw 1 in the longitudinal direction. The Y-shaped groove 9 matches the dimensions of the notch 11 and prefabricated crack 12 of the same structure on the fracture toughness specimen 10, limiting the machining depth of the notch 11 and prefabricated crack 12 on the fracture toughness specimen 10.

[0038] The two vertical surfaces of the groove within the reference positioning U-shaped block 6 serve as reference positioning surfaces for the fracture toughness specimen 10, ensuring that the fracture toughness specimen 10 to be processed is perpendicular to the Y-shaped groove 9, and that the V-shaped portion at the bottom of the notch 11 is at the same height as the V-shaped groove in the middle of the Y-shaped groove 9. The L-shaped gasket 8 is placed on the larger surface of the fracture toughness specimen 10. The disc bolt 7 passes through the threaded hole on the larger surface of the reference positioning U-shaped block 6 to press the L-shaped gasket 8 tightly, securing the fracture toughness specimen 10. The L-shaped gasket 8 protects the surface of the fracture toughness specimen 10 from being scratched by the rotating pressure of the disc bolt 7.

[0039] like Figure 4 As shown, the operating method of the present invention is as follows:

[0040] Place the end face of fracture toughness specimen 10 against end face positioning block 5, with the long side and large side respectively touching the bottom and side of reference positioning U-shaped block 6. Rotate disc bolt 7 to secure the specimen. Manually insert the custom Y-shaped saw blade 4 into the Y-shaped slot 9 with the teeth facing downward. Use both hands to reciprocate the Y-shaped saw 1 in the slot 9 while applying downward force until the middle V-shaped portion of the custom Y-shaped saw blade 4 contacts the slot 9. Remove the custom Y-shaped saw blade 4 upward to complete the notch 11 and prefabricated crack 12 on fracture toughness specimen 10. Loosen the rotating disc bolt 7 and remove the fracture toughness specimen 10, completing the notch and prefabricated crack processing of fracture toughness specimen 10.

[0041] like Figure 5 As shown, the special grooving tool includes a grooving tool 13, a stepped shaft 14, a gasket 15, and a locking nut 16. The large end of the stepped shaft 14 is clamped on the tool handle of the vertical machining center / milling machine. The width and angles of the grooving tool 13 are consistent with the size of the notch 11 on the sample 10.

[0042] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any person skilled in the art can, without departing from the scope of the present invention, make many possible changes and modifications to the present invention by using the above technical content, or modify it into an equivalent embodiment with equivalent changes. Therefore, any changes, modifications, equivalent changes and modifications made to the above implementation based on the technology of the present invention without departing from the content of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A processing device for fracture toughness specimens of aviation non-metallic materials, characterized in that: The invention comprises a slotting tool, a Y-shaped saw (1), and a clamping and positioning fixture, wherein the slotting tool is used to process a notch (11) on a sample (10); the Y-shaped saw (1) comprises a handle (2) and a Y-shaped saw blade (4); the clamping and positioning fixture comprises a reference positioning U-shaped block (6), and the two vertical sides of the reference positioning U-shaped block (6) are respectively processed with Y-shaped grooves (9) having the same structure as the Y-shaped saw blade (4), and the Y-shaped grooves (9) comprise a rectangular groove in the upper part, a V-shaped groove in the middle part, and vertically distributed cracks; a sample (10) is clamped between the two vertical sides of the reference positioning U-shaped block (6), and the sample rests on the horizontal side of the reference positioning U-shaped block (6); the Y-shaped saw passes through the Y-shaped groove (9) and processes a prefabricated crack (12) on the sample (10) along the vertically distributed cracks; The Y-shaped saw (1) further comprises a clamping screw (3), a hole groove is processed in the center of the handle (2), and a threaded hole is processed on the side, the saw handle of the Y-shaped saw blade (4) is inserted into the hole groove of the handle (2), and the clamping screw (3) is screwed into the threaded hole on the side of the handle (2) to fasten the clamping screw (3) and the handle (2) together; Wherein, a threaded hole is processed on the large surface of one side of the reference positioning U-shaped block (6), and a through Y-shaped groove (9) is processed perpendicular to the large surface. The Y-shaped groove (9) has the same structure as the Y-shaped saw blade (4), and the Y-shaped groove (9) extends above. The extension length is more than 2 mm greater than the sum of the depths of the notch 11 and the prefabricated crack 12, which facilitates the positioning of the starting processing position of the Y-shaped saw (1) in the length direction and has a guiding function. The length of the crack below the Y-shaped groove (9) is greater than the size of the same structure on the Y-shaped saw blade (4), avoiding interference when processing the prefabricated crack (12) on the fracture toughness specimen (10); The slotting tool comprises a slotting tool (13), a stepped shaft (14), a gasket (15), and a locking nut (16); the large end of the stepped shaft (14) is clamped on a tool handle of a vertical machining center / milling machine; the width and angles of the slotting tool (13) are consistent with the size of the notch (11) on the sample (10); The notch (11) is composed of a rectangular and a V-shaped part. The vertical machining center / milling machine drives the slotting tool to rotate at a constant speed and feed horizontally to process the notch (11) in layers. The tool speed is 400 rpm to 1000 rpm, the cutting feed is 10 mm / s to 30 mm / s, and the layer cutting depth is 0.2 mm to 0.5 mm.

2. The processing device for the fracture toughness test specimen of aviation non-metallic materials according to claim 1, characterized in that: The samples (10) are fixed vertically on a vertical machining center / milling machine in groups of 3 to 20 pieces, and protective pieces made of the same material are added on both sides of the samples (10) to prevent the samples (10) from being chipped and pinched during machining.

3. The processing device for the fracture toughness test specimen of aviation non-metallic materials according to claim 1, characterized in that: The horizontal side of the reference positioning U-shaped block (6) is an end surface positioning block (5), which is connected to the two vertical sides of the reference positioning U-shaped block (6) by screws to locate the position of the notch (11) in length.

4. The processing device for the fracture toughness test specimen of aviation non-metallic materials according to claim 1, characterized in that: The two vertical inner side surfaces of the reference positioning U-shaped block (6) serve as reference positioning surfaces for the sample (10), ensuring that the large surface of the sample (10) to be processed is perpendicular to the Y-shaped groove (9), and that the V-shaped portion at the bottom of the notch (11) is at the same height as the V-shaped groove in the middle of the Y-shaped groove (9).

5. The processing device for the fracture toughness test specimen of aviation non-metallic materials according to claim 1, characterized in that: The clamping and positioning fixture also includes a disc-shaped bolt (7) and an L-shaped gasket (8). The L-shaped gasket (8) is placed on the large surface of the sample (10). The disc-shaped bolt (7) passes through the threaded hole on the large surface of the reference positioning U-shaped block (6) to press the L-shaped gasket (8) to fix the sample (10). The L-shaped gasket (8) prevents the surface of the sample (10) from being scratched by the rotation and compression of the disc-shaped bolt (7).

6. The processing device for the fracture toughness test specimen of aviation non-metallic materials according to claim 1, characterized in that: The sample (10) is a rectangular sample, one side of which needs to be processed with a notch (11) and a prefabricated crack (12). The shape of the notch (11) includes but is not limited to a V-shape, the maximum width of the notch is 2mm to 5mm, and the notch depth is 2mm to 8mm. The material includes organic glass, carbon fiber composite and non-metallic materials for aviation.

7. A method for processing prefabricated cracks in aviation non-metallic materials, characterized by: A processing device as described in any one of claims 1 to 6 is selected, wherein the Y-shaped saw blade (4) is pre-installed in the Y-shaped groove (9), the Y-shaped saw (1) is controlled to move back and forth in the Y-shaped groove (9) and force is applied downward to the Y-shaped saw (1) until the middle V-shaped portion of the Y-shaped saw blade (4) contacts the V-shaped portion of the Y-shaped groove (9), and the Y-shaped saw blade (4) is removed upward to achieve processing of the prefabricated crack (12) on the fracture toughness specimen (10).

8. The method for processing prefabricated cracks in aviation non-metallic materials according to claim 7, characterized in that: The Y-shaped saw blade (4) is similar in shape to the notch (11) and the prefabricated crack (12) on the fracture toughness specimen (10), with the upper portion being rectangular, the middle portion being V-shaped, and the lower portion being a vertically distributed thin plate, and the saw teeth being located on the vertically distributed thin plate in the lower portion. The size of the Y-shaped saw blade (4) is substantially similar to the notch (11) and the prefabricated crack (12) on the fracture toughness specimen (10), with the only difference being that the overall width is 0.01 mm to 0.02 mm smaller than the width of the notch (11) and the prefabricated crack (12).

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