Manufacturing method of wedge-shaped composite material ultrasonic detection reference block

Abstract

The invention belongs to the technical field of nondestructive testing, and relates to a manufacturing method of a wedge-shaped composite material ultrasonic testing reference block. The method comprises the following steps: designing a multi-step false piece of a reference block on the basis of a paving layer of a part and the thickness of the part after machining; after the false part is cured, laying layers on the false part, increasing the length layer by layer, reducing the length layer by layer when the false part is laid to the longest position, and curing to form a wedge-like shape; and finally, polishing and repairing each step of the reference block by using fine sand to form the wedge-shaped reference block similar to the part.

Description

Technical Field

[0001] This invention belongs to the field of nondestructive testing technology and relates to a method for fabricating a wedge-shaped composite material ultrasonic testing comparison block. Background Technology

[0002] Composite materials have been widely used in aerospace and other fields due to their unique advantages, and there are more and more complex shaped structural parts. Composite material parts are prone to defects such as delamination, inclusions and pores during the manufacturing process. In particular, delamination and inclusion defects have a very negative impact on the function and service life of the parts. Therefore, it is extremely necessary to conduct ultrasonic testing on composite material parts.

[0003] To meet functional requirements, the manufacturing process for a certain type of composite material part is as follows: lay-up, curing, and machining, resulting in a wedge-shaped part. The fabrication of the ultrasonic testing comparison block for this part presents significant challenges. 1. The placement of artificial defects in the ultrasonic testing comparison test block has certain requirements. The artificial defect placement areas are between the second and third layers near the surface, the middle layer, and between the second and third layers on the lower surface. If the artificial defect position cannot be accurately controlled according to the manufacturing process of the part, it is easy to be processed away by the machining process or the defect position is not in the preset position, which cannot meet the requirements of the testing standard, and the comparison test block is a non-conforming test block. 2. For ultrasonic testing comparison blocks of wedge-shaped composite material parts, the industry generally uses multiple planar blocks of different thicknesses. This method has the problem of insufficient test representativeness, that is, the shape of the comparison block cannot effectively represent the shape of the tested part, and there is also a certain gap with the requirements of the test standard. It is necessary to develop a new comparison block testing method. Summary of the Invention

[0004] The technical problem to be solved by this invention is: based on the requirements of representativeness of ultrasonic testing comparison blocks and controllability of defect location for testing of wedge composite material parts, analyze the technical difficulties of the manufacturing method of ultrasonic comparison blocks for wedge composite material parts, and find the best manufacturing method so that the manufactured ultrasonic testing comparison blocks can meet both the requirements of representativeness of part shape and controllability of defect arrangement.

[0005] The technical solution of the present invention is A method for fabricating a wedge-shaped composite material ultrasonic testing comparison block is provided, comprising: Based on the layup of the parts and the thickness of the parts after machining, a multi-step dummy for comparison test blocks was designed; After the dummy part has cured, layers are laid on it, increasing the length layer by layer. When the longest layer is reached, the length is decreased layer by layer, and the layer is cured to form a wedge shape. Finally, the steps of the comparison test block were polished and repaired with fine sand to form a wedge-shaped comparison test block similar to the part.

[0006] Furthermore, after the dummy part has cured, before applying the layup layer on the dummy part, the method further includes: After the dummy test block has cured and formed, the excess parts on the edges are trimmed to ensure that it does not affect the subsequent laying of the dummy test block; The dummy test block was fixed to the entire surface of the flat tooling using a release cloth, ensuring that the release cloth could completely adhere to the entire surface of the dummy.

[0007] Furthermore, layering is performed on the dummy, including: Start by laying up the thinnest layer of the dummy and place artificial defects according to the test block drawing. Increase the length of each layer until the longest layer is reached. After the longest layer is completed, continue laying up layers, decreasing the length of each layer until all layers of the comparison test block are completed.

[0008] Furthermore, the solidification forms a wedge-like shape, including: After the layup is completed, the control block and the dummy are put into the autoclave for curing. After curing, the excess parts of the edges are trimmed.

[0009] Furthermore, the length is increased by 10mm for each layer.

[0010] Furthermore, the height is increased by 10mm for each layer.

[0011] Furthermore, based on the part's layup and the thickness of the machined part, a multi-step dummy for comparison was designed, including: Based on the part's layup and the thickness of the machined part, and taking into account the width of the ultrasonic testing comparison block, a multi-step dummy was designed for the comparison block. The thickness of the dummy at each location was half the thickness of the corresponding location of the machined part.

[0012] The beneficial effects of this application are as follows: This invention provides a method for manufacturing a wedge-shaped composite material ultrasonic testing comparison block. The manufacturing method is clear and can effectively control the placement of artificial defects and effectively represent the structural form of the inspected part, thereby ensuring the validity of the test results of this type of part. Attached Figure Description

[0013] Figure 1 Design drawings for dummy parts; Figure 2 This is a schematic diagram of the test block being laid up on the dummy. Figure 3 This is a schematic diagram of the test block layup and the placement of artificial defects. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0015] In the description of this invention, it should be understood that the terms "center", "axial", "vertical", "upper", "lower", "upper end", "bottom end", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0016] This invention is based on the layup of the parts and the thickness of the parts after machining, and designs a multi-step dummy for comparison (such as...). Figure 1 The shrinkage between adjacent layups of the dummy component is 10mm. After the dummy component has cured, layups are then performed on it, increasing the length of each layup by 10mm. When the longest layup is reached, the length of each layup is decreased, curing to form a wedge-like shape (e.g., Figure 2 and Figure 3 Finally, the steps of the comparison test block were polished and repaired with fine sand to form a wedge-shaped comparison test block similar to the part.

[0017] This invention provides a method for fabricating a wedge-shaped composite material ultrasonic testing comparison block, specifically including: 1. Based on the layup of the parts and the thickness of the parts after machining, design multi-step dummy parts and comparative test blocks; 2. Comparison Specimen Design: The thickness of the comparison specimen should be consistent with the thickness of the part. The corresponding number of ply layers can be calculated based on the thickness of the ply material. Simultaneously, the distance between defects and the distance from defects to the edge of the part should be fully considered. The designed distance between defects and the distance from defects to the edge of the part should not be less than 45mm. Defect placement is generally selected at the thickest point, the middle thickness, the thinnest point (when the part thickness is large, artificial defects can be placed at other thicknesses), between the second and third layers near the surface, the middle layer, and between the second and third layers on the lower surface. Increase the number of ply layers gradually from the minimum number until the maximum number of ply layers is reached. The shrinkage between adjacent ply layers is 10mm (e.g., ...). Figure 3 At the minimum and maximum thickness points, a length of not less than 45mm should be reserved; 3. Design of a multi-step dummy for the comparison test block: The width of the ultrasonic testing comparison test block should be fully considered. The width of the dummy must be greater than the width of the ultrasonic testing comparison test block. The thickness of the dummy at each location should be half the thickness of the corresponding location on the machined part. The maximum and minimum thickness points can be calculated based on the thickness of the ply material to determine the corresponding number of ply layers. The number of ply layers should be increased gradually from the minimum number of ply layers until the maximum number of ply layers is reached. The shrinkage between adjacent ply layers should be 10 mm (e.g., ...). Figure 1 At the minimum and maximum thickness points, a length of not less than 50 mm should be reserved so that the comparison test block has a length of not less than 45 mm at that position. 4. On the flat tooling, according to the design drawings of the comparison test block dummy, lay the composite prepreg layer by layer and vacuum it. During the laying process, pay attention to the air removal action to avoid large displacement of the layup, which would lead to the failure of the dummy production. 5. According to the manufacturing process parameters of the parts, the dummy parts are placed in an autoclave for curing and molding; 6. After the dummy test block has cured and formed, trim off any excess material around the edges of the dummy test block, and chamfer the edges appropriately. After trimming, the width of the dummy test block (excluding the chamfer) should be greater than the width of the dummy test block. 7. Fix the comparative test block dummy to the flat tooling using a release cloth. During the fixing process, ensure that the release cloth is completely in contact with the entire area of ​​the dummy to avoid leaving an air layer that could cause the shape of the comparative test block to change. 8. After fixing the dummy test piece, begin layering from the thinnest point of the dummy and place artificial defects at the positions specified in the design drawings of the dummy test piece. Increase the length of each layer by 10mm until the longest point of the dummy test piece is reached. After completing the layering at the longest point, continue layering, decreasing the length of each layer by 10mm. A layering diagram is shown below. Figure 2 Continue until all layers of the control test block are completed; 9. Print out the numbers of the control test blocks on plain paper (it is recommended to use a size 3 font), cut along the edge of the number, and place the cut control test block number on top of the last layer of cloth, at the edge of the thickest part of the length (the control test block number can be permanently retained after curing). 10. After the layup is completed, the control block and the dummy are put into an autoclave for curing. The curing parameters are the same as those of the part. After curing, the excess parts on the edge are trimmed, and the steps of the adjacent layup of the control block are carefully polished and repaired with fine sand to form a wedge shape similar to the shape and structure of the part.

[0018] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0019] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for fabricating a wedge-shaped composite material ultrasonic testing comparison block, characterized in that, include: Based on the layup of the parts and the thickness of the parts after machining, a multi-step dummy for comparison test blocks was designed; After the dummy part has cured, layers are laid on it, increasing the length layer by layer. When the longest layer is reached, the length is decreased layer by layer, and the layer is cured to form a wedge shape. Finally, the steps of the comparison test block were polished and repaired with fine sand to form a wedge-shaped comparison test block similar to the part.

2. The method according to claim 1, characterized in that, After the dummy component has cured, before applying the layup layer on the dummy component, the method further includes: After the dummy test block has cured and formed, the excess parts on the edges are trimmed to ensure that it does not affect the subsequent laying of the dummy test block; The dummy test block was fixed to the entire surface of the flat tooling using a release cloth, ensuring that the release cloth could completely adhere to the entire surface of the dummy.

3. The method according to claim 2, characterized in that, Layering is performed on the dummy, including: Start by laying up the thinnest layer of the dummy and place artificial defects according to the test block drawing. Increase the length of each layer until the longest layer is reached. After the longest layer is completed, continue laying up layers, decreasing the length of each layer until all layers of the comparison test block are completed.

4. The method according to claim 3, characterized in that, The solidification forms a wedge-like shape, including: After the layup is completed, the control block and the dummy are put into the autoclave for curing. After curing, the excess parts of the edges are trimmed.

5. The method according to claim 1, characterized in that, The length increases by 10mm with each layer.

6. The method according to claim 1, characterized in that, The height increases by 10mm with each layer.

7. The method according to claim 1, characterized in that, Based on the part's layup and post-machining thickness, a multi-step dummy for comparison was designed, including: Based on the part's layup and the thickness of the machined part, and taking into account the width of the ultrasonic testing comparison block, a multi-step dummy was designed for the comparison block. The thickness of the dummy was half the thickness of the machined part.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1-7.

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