Composite material wind tunnel test piece bonding and positioning auxiliary tool and method based on preparation of wind tunnel test piece

Abstract

The invention discloses an auxiliary tool for bonding and positioning a composite material wind tunnel test piece and a method for preparing the wind tunnel test piece. The bonding positioning auxiliary tool comprises an upper pressing plate, a lower pressing plate, bolts and nuts, through holes are formed in the end portions of the cross ends of the upper pressing plate and the lower pressing plate, and the upper pressing plate and the lower pressing plate are connected and fixed through the bolts and the nuts through the through holes; guide columns are arranged between the end of the upper surface of the lower pressing plate and the through holes, guide column holes are formed between the end of the upper pressing plate and the through holes, and the guide column holes correspond to the guide columns one to one in number and position. A clamping key is arranged beside each through hole, and a guide sleeve is arranged on the outer side of each guide column. The tool is used for bonding a metal material aluminum / steel and a composite material through a bonding agent, so that the uniformity and consistency of the prepared composite material wind tunnel test piece are guaranteed, and the heat insulation property and the ablation property of the composite material can be better reflected.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly relates to an auxiliary tool for bonding and positioning a wind tunnel test piece of a composite material and a method for preparing a wind tunnel test piece based on the composite material. Background Art

[0002] In the aerospace field, when an aircraft flies at hypersonic speed in the atmosphere, there will be intense friction between the surface of the aircraft and the air, resulting in the phenomenon of aerodynamic heating, which causes the surface temperature of the aircraft to rise sharply. To ensure the strength of the main structure of the aircraft and the safety of internal instruments and equipment, a thermal protection system must be set on the outer surface of the aircraft. The thermal protection system is an important part of the aircraft. According to the different working conditions of each part of the aircraft, the thermal protection methods are divided into three types: passive, semi-passive, and active. As a passive thermal protection material, resin-based composite materials are still considered to be the most effective, reliable, mature, and economical thermal protection materials. The thermal conductivity and ablation performance of the materials are the key factors determining the reliability of thermal protection. Wind tunnel tests can effectively simulate the heat insulation and ablation conditions of the materials during flight.

[0003] A wind tunnel test piece is a model or component used in wind tunnel experiments to characterize the heat insulation and ablation conditions of materials during flight and is the key to testing the reliability of thermal protection materials. The auxiliary tool for bonding and positioning a wind tunnel test piece is mainly used to accurately fix and position the test piece in a wind tunnel experiment to ensure its stability and accuracy during the test. This tool usually consists of high-precision mechanical components and positioning devices and can adapt to test pieces of different shapes and sizes.

[0004] Currently, the existing bonding tools are mostly used to prepare specimens such as tensile shear to evaluate the performance of adhesives. For example, Patent CN113970470A discloses an auxiliary tool and a bonding method for a composite material tensile shear test body. This bonding tool and method do not introduce a third phase. Through reasonable bonding tool design, the degrees of freedom of the substrate in three directions are limited, and the area and thickness of the adhesive layer are accurately controlled, so as to realize the preparation of high-precision composite material tensile shear test bodies and meet the application requirements of long-term environmental aging tests. Patent CN217156002U discloses a production mold for adhesive tensile shear test pieces. This mold can adjust and control the sizes of the bonding substrate and the adhesive, has high adaptability, and is suitable for popularization and application. However, currently, they are all bonding and positioning tools for composite material tensile shear test bodies, lacking research on bonding and positioning tools for composite material wind tunnel test pieces and methods for preparing composite material wind tunnel test pieces based on them. Summary of the Invention

[0005] In view of the problems existing in the above-mentioned background art, the present invention provides an auxiliary tooling for bonding and positioning a composite material wind tunnel test piece and a method for preparing a wind tunnel test piece, which are used to bond a metal material aluminum / steel and a composite material through an adhesive, and can ensure the uniformity and consistency of the composite material wind tunnel test piece, so as to better reflect the heat insulation and ablation performance of the composite material.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] An auxiliary tooling for bonding and positioning a composite material wind tunnel test piece includes an upper pressing plate, a lower pressing plate, bolts and nuts;

[0008] The upper pressing plate and the lower pressing plate have the same shape and size, and are both cross-shaped plates or quasi-cross-shaped plates; through holes are provided at each end of the cross ends of the upper pressing plate and the lower pressing plate, and the upper pressing plate and the lower pressing plate are connected and fixed by bolts and nuts through the through holes;

[0009] Guide posts are arranged between the upper surface end of the lower pressing plate and the through holes, and the guide posts are symmetrically and parallelly distributed around the upper surface of the lower pressing plate; guide post holes are arranged between the end of the upper pressing plate and the through holes, and the number and positions of the guide post holes correspond to those of the guide posts one by one; the guide posts and the guide post holes are used to position the upper pressing plate and the lower pressing plate;

[0010] Clamping keys are provided beside each through hole on the lower surface of the upper pressing plate and the upper surface of the lower pressing plate. The clamping keys are distributed inside the guide posts and the guide post holes, symmetrically distributed on both sides of the guide posts and the guide post holes, and the through holes are distributed between the guide posts, the guide post holes and the clamping keys; the clamping keys are used to accurately fix the position of the composite material wind tunnel test piece;

[0011] A guide sleeve is respectively arranged outside each of the guide posts. The inner part of the guide sleeve is conformable to the guide post, and the guide sleeve is used to accurately control the thickness of the adhesive layer between the composite material and the metal material, and further accurately control the height of the composite material wind tunnel test piece to make it consistent.

[0012] Further, a composite material is arranged in the clamping key of the lower pressing plate of the present invention, and a metal material is arranged in the clamping key of the upper pressing plate. Moreover, the distance between the clamping key and the through hole arranged on the upper pressing plate is greater than the distance between the two arranged on the lower pressing plate, and the distance ratio between the two is limited according to the actual product requirements; the height of the clamping key is less than the material thickness and greater than half of the material thickness.

[0013] Further, a guide sleeve is respectively arranged outside each of the guide posts of the present invention. The material of the guide sleeve is steel, and the outer shape of the guide sleeve is a cylinder, a cube or a cuboid.

[0014] Further, the positions of the through holes on the upper pressing plate and the lower pressing plate are distributed in one-to-one correspondence, and the number of through holes provided at each end is the same; preferably, the upper pressing plate and the lower pressing plate each have 4 to 8 through holes.

[0015] Further, the lower pressing plate of the present invention is provided with 2 to 4 guide posts, which are parallelly distributed on the upper surface of the lower pressing plate; the upper pressing plate has 2 to 4 guide post holes.

[0016] Further, the lower pressing plate and the upper pressing plate of the present invention are each provided with 4 to 8 keyways, and the number of keyways corresponds to the through holes one by one.

[0017] Further, the present invention also provides a method for preparing a wind tunnel test piece based on the above-mentioned bonding positioning auxiliary tooling, including the following steps:

[0018] (1) Sandblasting / grinding treatment of the bonding surface of the wind tunnel sample: Grind the bonding surface of the wind tunnel sample 1 respectively, and sandblast the bonding surface of the wind tunnel sample 2;

[0019] The wind tunnel sample 1 is made of metal material, and the bonding surface is polished with sandpaper to make the bonding surface new and have obvious scratches, and the mesh number of the sandpaper is 36 to 120 meshes;

[0020] The wind tunnel sample 2 is made of composite material, and white corundum sand is sprayed on the bonding surface for sandblasting treatment, the sandblasting pressure is 0.4 to 0.8 MPa, and the mesh number of the white corundum sand is 35 to 50 meshes;

[0021] (2) Cleaning of the bonding surface of the wind tunnel sample: Remove the dust from the wind tunnel sample 1 and the wind tunnel sample 2, and then wipe the bonding surface with a cotton cloth or cotton yarn dipped in a reagent, and the drying time is ≥ 15 min;

[0022] The reagent is acetone, ethanol or ethyl acetate;

[0023] (3) Pretreatment of the tooling: Coat silicone grease on the inner sides of all the keyways of the upper pressing plate and the lower pressing plate for convenient demoulding later;

[0024] (4) Positioning of the wind tunnel sample: Snap the wind tunnel sample 1 into the keyways of the lower pressing plate, and snap the wind tunnel sample 2 into the keyways of the upper pressing plate, both exposing the bonding surface;

[0025] (5) Glue application specification for the wind tunnel sample: Dip a glue application tooling into the glue liquid, and apply the glue liquid to the bonding surfaces of the wind tunnel sample 1 and the wind tunnel sample 2 in one direction, and visually check for no missed application;

[0026] (6) Pressurization method: Align the guide post holes on the upper pressing plate with the guide posts on the lower pressing plate, move downward along the direction of the guide posts until the upper pressing plate no longer moves downward, fix each component with bolts and nuts, and use a torque wrench to tighten the nuts symmetrically and crosswise so that the same torque value is maintained during the tightening process of each nut; After the pressurization is completed, the excess glue liquid that overflows needs to be cleaned up;

[0027] The glue liquid cleaning method is to wipe the bonding surface with a cotton cloth or cotton yarn dipped in a reagent, and the reagent is acetone, ethanol or ethyl acetate;

[0028] (7) Curing process: After the two wind tunnel specimens are bonded, room temperature curing or high temperature curing is used to obtain the composite material wind tunnel specimen;

[0029] The room temperature curing time is greater than 24h; the high temperature curing temperature is 50-75°C, and the curing time is greater than 2h;

[0030] (8) Removing the tooling: After the adhesive is cured, remove the bolts and nuts, and take out the composite material wind tunnel specimen for testing the heat insulation performance and ablation performance of the composite material.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The high-precision bonding and positioning auxiliary tooling for the composite material wind tunnel specimen of the present invention can accurately control the thickness of the adhesive layer between the aluminum sheet and the composite material, and accurately position the composite material and the aluminum sheet, which can ensure the uniformity and consistency of the composite material wind tunnel specimen, and thus better reflect the heat insulation and ablation performance of the composite material;

[0033] (2) The overall tooling of the present invention has the characteristics of small volume, light weight, convenient movement, convenient operation, short sample preparation time and high precision. Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of the high-precision bonding and positioning auxiliary tooling for the composite material wind tunnel specimen of the present invention.

[0035] Figure 2 It is a schematic structural diagram of the lower pressing plate in the high-precision bonding and positioning auxiliary tooling of the present invention.

[0036] Figure 3 It is a schematic structural diagram of the upper pressing plate in the high-precision bonding and positioning auxiliary tooling of the present invention.

[0037] Figure 4 It is a schematic structural diagram of sample preparation using the high-precision bonding and positioning auxiliary tooling structure of the present invention.

[0038] Each label in the figure is: 1 lower pressing plate, 2 upper pressing plate, 3 bolt, 4 nut, 5 guide post, 6 guide sleeve, 7 key, 8 through hole, 9 guide post hole, 10 wind tunnel specimen 1, 11 wind tunnel specimen 2. Detailed Embodiments

[0039] The present invention will be further described in detail below in conjunction with the drawings, but the content of the present invention is not limited to the following embodiments.

[0040] Embodiment

[0041] Such as Figure 1 、Figure 2 , Figure 3 As shown in Figure 3 , an adhesive positioning and assisting tooling for a composite material wind tunnel test piece includes an upper pressing plate 2, a lower pressing plate 1, bolts 3 and nuts 4;

[0042] The upper pressing plate 2 and the lower pressing plate 1 are identical in shape and size, and are both cross-shaped plates or quasi-cross-shaped plates; through holes are provided at each end of the cross ends of the upper pressing plate 2 and the lower pressing plate 1, and the upper pressing plate 2 and the lower pressing plate 1 are connected and fixed by bolts 3 and nuts 4 through the through holes 8;

[0043] Guide posts 5 are arranged between the end of the upper surface of the lower pressing plate 1 and the through hole 8, and the guide posts are symmetrically and parallelly distributed around the upper surface of the lower pressing plate; guide post holes 9 are arranged between the end of the upper pressing plate 2 and the through hole 8, and the number and positions of the guide post holes 9 correspond one by one to those of the guide posts 8; the guide posts 8 and the guide post holes 9 are used to position the upper pressing plate 2 and the lower pressing plate 1;

[0044] Clamping keys 7 are provided beside each through hole on the lower surface of the upper pressing plate 2 and the upper surface of the lower pressing plate 1. The clamping keys are distributed inside the guide posts and the guide post holes, symmetrically distributed on both sides of the guide posts and the guide post holes, and the through holes are distributed between the guide posts and the guide post holes and the clamping keys; the clamping keys are used to accurately fix the position of the composite material wind tunnel test piece;

[0045] A guide sleeve 6 is respectively arranged on the outside of each guide post 8. The inside of the guide sleeve is conformable to the guide post. The guide sleeve is used to accurately control the thickness of the adhesive layer between the composite material and the metal material, and further accurately control the height of the composite material wind tunnel test piece to make it consistent.

[0046] A composite material is arranged inside the clamping key of the lower pressing plate, and a metal material is arranged inside the clamping key of the upper pressing plate. Moreover, the distance between the clamping key and the through hole arranged on the upper pressing plate is greater than the distance between the two arranged on the lower pressing plate, and the distance ratio between the two is limited according to the actual product requirements; the height of the clamping key is less than the material thickness and greater than half of the material thickness;

[0047] A guide sleeve is respectively arranged on the outside of each guide post. The material of the guide sleeve is steel, and the outer shape of the guide sleeve is a cylinder;

[0048] The positions of the through holes on the upper pressing plate and the lower pressing plate are distributed in one-to-one correspondence, and the number of through holes provided at each end is the same; both the upper pressing plate and the lower pressing plate are each provided with 8 through holes;

[0049] 4 guide posts are provided on the lower pressing plate, and are parallelly distributed on the upper surface of the lower pressing plate; the upper pressing plate has 4 guide post holes;

[0050] Both the lower pressing plate and the upper pressing plate are each provided with 8 clamping keys, and the number of clamping keys corresponds one by one to the through holes.

[0051] A method for preparing a wind tunnel test piece based on the above adhesive positioning and assisting tooling includes the following steps:

[0052] (1) Sandblasting / grinding treatment of the bonding surface of the wind tunnel sample pieces: Grind the bonding surface of the wind tunnel sample piece 1 respectively, and sandblast the bonding surface of the wind tunnel sample piece 2;

[0053] The wind tunnel sample 1 is made of metal material. The bonding surface is ground with sandpaper to make the bonding surface new and have obvious scratches, and the mesh number of the sandpaper is 120 mesh;

[0054] The wind tunnel sample piece 2 is a composite material. White fused alumina sand is sprayed on the surface of the bonding surface for sandblasting treatment. The sandblasting pressure is 0.4 - 0.8 MPa, and the mesh number of the white fused alumina sand is 46 mesh;

[0055] (2) Cleaning of the bonding surface of the wind tunnel sample pieces: Remove the dust from the wind tunnel sample piece 1 and the wind tunnel sample piece 2, and then wipe the bonding surface with a cotton cloth or cotton yarn dipped in a reagent, and the drying time ≥ 15 min;

[0056] The reagent is acetone;

[0057] (3) Pretreatment of the tooling: Apply silicone grease on the inner sides of all the clamping keys of the upper pressing plate and the lower pressing plate for convenient demolding later;

[0058] (4) Positioning of the wind tunnel sample pieces: Clamp the wind tunnel sample piece 1 into the clamping keys of the lower pressing plate, and clamp the wind tunnel sample piece 2 into the clamping keys of the upper pressing plate, both exposing the bonding surface;

[0059] (5) Gluing specification of the wind tunnel sample pieces: Dip a glue application tooling into the glue liquid, and apply it to the bonding surfaces of the wind tunnel sample piece 1 and the wind tunnel sample piece 2 in one direction, and visually check for no missed coating;

[0060] (6) Pressing method: Align the guide post holes on the upper pressing plate with the guide posts on the lower pressing plate, move downward along the direction of the guide posts until the upper pressing plate no longer moves downward, fix each component with bolts and nuts, and use a torque wrench to tighten the nuts symmetrically and crosswise to keep the same torque value during the tightening process of each nut; After the pressing is completed, the excess glue liquid that overflows needs to be cleaned up;

[0061] The method for cleaning the glue liquid is to wipe the bonding surface with a cotton cloth or cotton yarn dipped in a reagent, and the reagent is alcohol;

[0062] (7) Curing process: After the two wind tunnel sample pieces are bonded, room temperature curing is adopted to obtain a composite material wind tunnel test piece; The room temperature curing time is 24 h;

[0063] (8) Removal of the tooling: After the adhesive is cured, remove the bolts and nuts, take out the composite material wind tunnel test piece for testing the heat insulation performance and ablation performance of the composite material.

Claims

1. A composite material wind tunnel test piece bonding positioning auxiliary tooling, characterized in that: The bonding positioning auxiliary tooling comprises an upper pressing plate (2), a lower pressing plate (1), bolts (3) and nuts (4); The upper pressing plate (2) and the lower pressing plate (1) are of the same shape and size, and are both cross-shaped plates or quasi-cross-shaped plates; each cross end of the upper pressing plate (2) and the lower pressing plate (1) is provided with a through hole (8), and the upper pressing plate (2) and the lower pressing plate (1) are connected and fixed by bolts (3) and nuts (4) through the through holes (8); A guide post (5) is arranged between the end of the upper surface of the lower pressing plate (1) and the through hole (8), and the guide posts are symmetrically and parallelly distributed around the upper surface of the lower pressing plate; a guide post hole (9) is arranged between the end of the upper pressing plate (2) and the through hole (8), and the number and position of the guide post holes correspond to the guide posts one by one; A key (7) is provided beside each through hole (8) on the lower surface of the upper pressing plate (2) and the upper surface of the lower pressing plate (1); the key (7) is distributed inside the guide post (5) and the guide post hole (9), symmetrically distributed on both sides of the guide post and the guide post hole, and the through holes are distributed between the guide post and the guide post hole and the key; A guide sleeve (6) is arranged on the outside of each guide post (5), and the inside of the guide sleeve (6) is in the same shape as the guide post.

2. The composite material wind tunnel test piece bonding and positioning auxiliary tooling according to claim 1, characterized in that: A composite material is arranged in the key of the lower pressing plate (1), a metal material is arranged in the key of the upper pressing plate (2), and the distance between the key and the through hole arranged in the upper pressing plate is greater than the distance between the two arranged in the lower pressing plate; The height of the key (7) is less than the material thickness and greater than half of the material thickness.

3. The composite material wind tunnel test piece bonding and positioning auxiliary tooling according to claim 1, characterized in that: The guide sleeve (6) is made of steel, and its outer shape is a cylinder, a cube or a cuboid.

4. The composite material wind tunnel test piece bonding and positioning auxiliary tooling according to claim 1, characterized in that: The positions of the through holes (8) on the upper pressing plate (2) and the lower pressing plate (1) correspond one to one, and the number of through holes at each end is consistent, with each of the upper pressing plate and the lower pressing plate being provided with 4 to 8 through holes.

5. The composite material wind tunnel test piece bonding and positioning auxiliary tooling according to claim 1, characterized in that: The lower pressing plate (1) is provided with 2 to 4 guide pillars, which are distributed in parallel on the upper surface of the lower pressing plate; The upper pressing plate (2) has 2 to 4 guide post holes.

6. The composite material wind tunnel test piece bonding and positioning auxiliary tooling according to claim 1, characterized in that: The lower pressing plate (1) and the upper pressing plate (2) are each provided with 4 to 8 latching keys (7), and the number of latching keys corresponds to the number of through holes.

7. A method for preparing a wind tunnel specimen based on the bonding positioning auxiliary tooling according to any one of claims 1 to 6, characterized in that: The steps include: (1) Sandblasting / grinding of the bonding surface of the wind tunnel specimens: The bonding surface of wind tunnel specimen 1 is ground, and the bonding surface of wind tunnel specimen 2 is sandblasted; (2) Cleaning of the bonding surface of wind tunnel specimens: Remove dust from wind tunnel specimens 1 and 2, then wipe the bonding surface with a cotton cloth or cotton yarn dipped in the reagent and leave it in the air for ≥15 min; The reagent is acetone, ethanol or ethyl acetate; (3) Tooling pretreatment: Apply silicone ester on the inner side of all the keys on the upper and lower pressing plates; (4) Wind tunnel sample positioning: insert wind tunnel sample 1 into the key of the lower pressing plate, and insert wind tunnel sample 2 into the key of the upper pressing plate, with both surfaces exposed; (5) Wind tunnel specimen gluing specification: Use a gluing tool to dip the glue into the glue and apply it to the bonding surfaces of wind tunnel specimen 1 and wind tunnel specimen 2 in one direction. Visually check that there is no missing glue. (6) Pressurization method: Use the guide post hole on the upper pressure plate to align with the guide post of the lower pressure plate, move downward along the guide post until the upper pressure plate stops moving downward, fix the components with bolts and nuts, and use a torque wrench to tighten the nuts symmetrically and crosswise, so that the same torque value is maintained during the tightening process of each nut; after the pressurization is completed, the excess glue that has overflowed needs to be cleaned up; (7) Curing process: After the two wind tunnel specimens are bonded, room temperature curing or high temperature curing is used to obtain the composite material wind tunnel specimen; (8) Removal of tooling: After the adhesive is cured, remove the bolts and nuts and take out the composite material wind tunnel specimen for testing the thermal insulation and ablation properties of the composite material.

8. The method according to claim 7, characterized in that: In step (1), the wind tunnel sample 1 is made of metal material, and the bonding surface is polished with sandpaper to make the bonding surface look new, and the mesh number of the sandpaper is 36 to 120; The wind tunnel sample 2 is a composite material, and white corundum sand is sprayed on the bonding surface for sandblasting. The sandblasting pressure is 0.4-0.8 MPa, and the white corundum sand mesh number is 35-50 meshes.

9. The method according to claim 7, characterized in that: The glue cleaning method in step (6) is to wipe the bonding surface with a cotton cloth or cotton yarn dipped in a reagent, wherein the reagent is acetone, ethanol or ethyl acetate.

10. The method according to claim 7, characterized in that: The room temperature curing time in step (7) is greater than 24 hours; the high temperature curing temperature is 50-75°C, and the curing time is greater than 2 hours.

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