A composite material pressure frame air pressure experimental testing device and testing method

Abstract

The application relates to the field of aircraft structure mechanical property testing technology, in particular to a composite material pressure frame air pressure experimental testing device, which comprises an air pressure cover plate for connecting joints of the air pressure cover plate and a pressure frame, when the air pressure cover plate and the pressure frame are buckled with each other, the joints are located between the air pressure cover plate and the pressure frame and are hinged together through hinges, the air pressure cover plate and the pressure frame are fixed together through the joints and enclose a closed space with an inner cavity, a pressurizing pipeline in the air pressure cover plate and a pressure gauge for detecting the pressure between the air pressure cover plate and the pressure frame. The application further discloses a composite material pressure frame air pressure experimental testing method, the application has good structural integrity of a tested test piece, and can truly reflect the effect of structural bearing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aircraft structure mechanical performance test technology, in particular to a kind of composite material pressure frame air pressure experimental test device and test method. BACKGROUND

[0002] Civil aircraft structure design widely adopts thin-walled structure. In order to reduce the weight of structure, resin-based composite material has become one of the mainstream materials of aircraft design because of its high specific stiffness and specific strength, corrosion resistance and other performances. With the higher flight altitude of aircraft, the smaller external environmental pressure. In order to improve the comfort of passengers, the passenger cabin of today's commercial aircraft adopts sealed pressurization to simulate the environment close to ground atmospheric pressure during flight as much as possible. Therefore, in order to uniformly bear the pressure difference of air pressure, reduce stress concentration and fuselage tension, the fuselage of civil aircraft is often designed into a circular or nearly circular shape. Moreover, the size of the circular cross section of modern aircraft fuselage is getting larger and larger. It is imperative to develop lightweight, high-strength, pressure-resistant and fatigue-resistant composite material pressure frame. In the prior art, large-size composite material integral pressure frame has been designed and applied to the fuselage structure of civil aircraft. However, whether each new pressure frame design can meet the design requirements, whether it can achieve the designed bearing performance, and how to verify have always been the focus of mechanical test design. The air-tightness test is one of the important tests for verifying the mechanical performance of pressure frame.

[0003] For the related technology in the above, the inventor believes that the air bag can only apply internal pressure load inside, and cannot apply external pressure load; and the air bag or direct pressure charging is used for pressure charging of sealed space, and the air bag is used for pressure charging of large-size curved wall plate space, and the air-tightness test cannot be performed; the length of the test piece is lengthened to change the body of the test piece, which destroys the test purpose, or the V-shaped or lengthened test piece is used to achieve assembly and connection, and the V-shaped connection structure is not conducive to disassembly and opening inspection. SUMMARY

[0004] In order to better maintain the structural integrity of the test piece to be tested, and to better reflect the bearing performance of the structure, the present application provides a kind of composite material pressure frame air pressure experimental test device and test method.

[0005] The composite material pressure frame air pressure experimental test device provided by the present application adopts the following technical scheme:

[0006] A kind of composite material pressure frame air pressure experimental test device, including gas pressure cover plate for connecting the joint of the gas pressure cover plate and pressure frame, when the gas pressure cover plate and pressure frame are mutually buckled, the joint is located between the gas pressure cover plate and pressure frame and is hinged together by hinge, and the gas pressure cover plate and pressure frame are fixed together by the joint and enclose airtight space with hollow interior, the pressure charging pipeline in the gas pressure cover plate and the pressure gauge for detecting the pressure between the gas pressure cover plate and pressure frame.

[0007] By adopting the technical scheme, the air-tightness of the pressure frame can be detected while the strength is detected, the air pressure cover plate is hinged with the pressure frame, the opening and closing of the pressure frame and the air pressure cover plate are facilitated, maintenance and damage introduction are facilitated, the connection of the pressure frame and the air pressure cover plate is ensured, the air-tightness of the two is maintained, the structural integrity of the tested test piece is better maintained, and the structural bearing performance can be more truly reflected.

[0008] Optionally, the joint is annular, the joint comprises a first connecting portion, a second connecting portion and a third connecting portion in a ring shape, the first connecting portion and the second connecting portion are mirror image arranged along the plate surface of the third connecting portion, the outer edge of the first connecting portion, the outer edge of the second connecting portion and the inner edge of the third connecting portion are fixed together, the first connecting portion is fitted with the inner side wall of the air pressure cover plate, the second connecting portion is fitted with the inner side wall of the pressure frame and is fixed together by a bolt, and the third connecting portion extends from between the air pressure cover plate and the pressure frame.

[0009] By adopting the technical scheme, the first connecting portion and the second connecting portion are mirror image arranged with the third connecting portion, so that the cross section between the three is Y-shaped, the air-tightness between the air pressure cover plate and the pressure frame can be ensured through the Y-shaped joint, the installation of the joint can be facilitated through the third connecting portion, the Y-shaped joint separates the internal pressure and external pressure load, is more targeted, the use of test device materials can be reduced, and material costs can be saved.

[0010] Optionally, the edge of the air pressure cover plate is provided with a connecting groove, the first connecting portion is provided with a clamping portion, and the air pressure cover plate and the first connecting portion are clamped together through the clamping groove and the clamping portion.

[0011] By adopting the technical scheme, the connection between the first connecting portion and the air pressure cover plate can be more stable through the connecting groove and the clamping portion, so that the air pressure cover plate and the connecting piece are prevented from being separated from each other under the action of air pressure, and the connection stability between the connecting piece and the air pressure cover plate is improved.

[0012] Optionally, the edge of the air pressure cover plate is provided with a flange, the third connecting portion is fitted with the flange, and a plurality of edge clamps are arranged between the flange and the third connecting portion to clamp the flange and the third connecting portion together.

[0013] By adopting the technical scheme, the connecting area between the air pressure cover plate and the third connecting portion is increased through the flange and the third connecting portion, and the air pressure cover plate and the connecting piece are further prevented from being separated from each other through the clamping of the edge clamps, and the test reliability is improved.

[0014] Optionally, a sealing strip is arranged between the joint and the air pressure cover plate and between the joint and the pressure frame.

[0015] By using the above technical solution, the sealing strip increases the air tightness between the joint and the air pressure cover plate and between the joint and the pressure frame, reduces the influence of equipment gaps on test results during testing, and increases the accuracy of test results.

[0016] Optionally, the sealing device for closing the wire hole on the pressure frame includes two oppositely arranged sealing plates and connecting bolts, one of the two sealing plates is attached to the A surface of the pressure frame, and the other sealing plate is attached to the B surface of the pressure frame, and the two sealing plates are pressed against the pressure frame by the connecting bolts.

[0017] By using the above technical solution, the two oppositely arranged sealing plates can cover both sides of the air hole. When the shell formed by the air pressure cover plate and the pressure frame is under positive pressure or negative pressure, the two sealing plates can seal the air hole in two states respectively.

[0018] Optionally, the sealing device further includes a core layer for supporting the two sealing plates.

[0019] By using the above technical solution, the core layer can support the two sealing plates when the sealing plates are subjected to air pressure, which can reduce the deformation of the sealing plates to a certain extent, reduce the damage of the sealing plates under stress, and improve the strength of the sealing plates.

[0020] Optionally, a sealing ring is arranged between the sealing plate and the pressure frame.

[0021] By using the above technical solution, the sealing ring can increase the air tightness of the device when the sealing plate is stressed and close to the pressure frame. The sealing rings on both sides of the pressure frame can seal the air hole under positive pressure and negative pressure respectively, reducing air leakage from the air hole.

[0022] Optionally, a sealing adhesive layer is arranged between the sealing plate and the A surface of the pressure frame.

[0023] By using the above technical solution, the adhesive layer is used to bond the sealing plate and the pressure frame, and at the same time, the adhesive layer fills the gaps between the connecting bolts, the air pressure cover plate and the sealing plate, thereby improving the air tightness of the whole device.

[0024] The composite pressure frame air pressure test method provided in the present application adopts the following technical solution:

[0025] A detection method using the composite pressure frame air pressure test device is provided, and the specific steps are as follows:

[0026] S1, assembly: the air pressure cover plate is connected with the pressure frame through the joint, and the joint and the air pressure cover plate are clamped through the edge clamping;

[0027] S2, stamping: the inside of the air pressure cover plate is stamped to the required value through the pressure pipeline, and air tightness detection is carried out after standing;

[0028] S4, negative pressure: the air pressure between the air pressure cover plate and the pressure frame is reduced to the required value through the pressure pipeline, and air tightness detection is carried out after standing;

[0029] S5, secondary pressure relief and cover inspection: the air pressure between the air pressure cover plate and the pressure frame is adjusted to normal pressure, the edge clamping is removed and the air pressure cover plate is opened, and the pressure frame is inspected.

[0030] By adopting the above technical scheme, the air tightness and air pressure test can be considered at the same time, and the ability of the test piece to resist internal pressure and external pressure can be tested; the composite material frame opening is sealed without processing the test piece, and the structural integrity of the test piece is maintained.

[0031] In summary, the present application includes at least one of the following beneficial technical effects:

[0032] 1. The air pressure cover plate is buckled together with the pressure frame, so that the air tightness of the pressure frame can be detected while the strength detection is carried out, the air pressure cover plate is hinged together with the pressure frame, which is convenient for opening and closing the pressure frame and the air pressure cover plate, is beneficial to maintenance and damage introduction, and through the connecting head, the air tightness of the pressure frame and the air pressure cover plate is ensured while the pressure frame and the air pressure cover plate are connected, the structural integrity of the test piece is better maintained, and the structural bearing performance can be more truly reflected;

[0033] 2. The first connecting part and the second connecting part are mirror image arranged with the third connecting part, so that the cross section between the three is Y-shaped, through the Y-shaped joint, the air tightness between the air pressure cover plate and the pressure frame can be ensured, and through the third connecting part, the installation of the joint can be facilitated, the Y-shaped joint separates the internal pressure and external pressure load, is more targeted, can reduce the use of test device materials, and saves material cost;

[0034] 3. The two oppositely arranged sealing plates can cover the two sides of the air hole, and when the shell formed by the air pressure cover plate and the pressure frame is subjected to positive pressure or negative pressure, the two sealing plates can seal the air hole in two states respectively. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a schematic diagram of the overall structure of a composite material pressure frame air pressure experimental test device.

[0036] Figure 2 This is a partial cross-sectional view of a composite material pressure frame air pressure test device in an embodiment of this application.

[0037] Figure 3 This is a cross-sectional view of the connector in an embodiment of this application.

[0038] Figure 4 This is a cross-sectional view of the connector connection in an embodiment of this application.

[0039] Figure 5 This is a cross-sectional view of the sealing device in an embodiment of this application.

[0040] Explanation of reference numerals in the attached drawings: 1. Pressure frame; 11. Sealing clamp; 2. Air pressure cover plate; 21. Groove; 22. Flanged edge; 3. Connector; 31. First connecting part; 311. Snap-fit ​​part; 312. Snap-fit ​​groove; 32. Second connecting part; 33. Third connecting part; 331. Hinge; 34. Bracket; 35. Sealing layer; 351. Sealing gasket; 352. Sealing strip; 4. Inflation chamber; 5. Inflation pipe; 6. Pressure gauge; 7. Sealing device; 71. Sealing plate; 72. Connecting bolt; 73. Sealing ring; 74. Core layer; 75. Adhesive layer. Detailed Implementation

[0041] The following is in conjunction with the appendix Figures 1-5 This application will be described in further detail.

[0042] This application discloses a composite material pressure frame air pressure test apparatus. (Refer to...) Figure 1 , Figure 2 A composite material pressure frame air pressure test device includes an air pressure cover plate 2 that matches the shape of a pressure frame 1, and a connector 3 for connecting the air pressure cover plate 2 and the pressure frame 1 together. The air pressure cover plate 2 and the pressure frame 1 are non-closed spherical shells with equal curvature. When the air pressure cover plate 2 and the pressure frame 1 are fastened together, the connector 3 is clamped between the air pressure cover plate 2 and the pressure frame 1, and the connector 3, together with the air pressure cover plate 2 and the pressure frame 1, forms an internally sealed shell, the interior of which is an inflation chamber 4. An inflation pipe 5 is fixedly connected to the air pressure cover plate 2, and the inflation chamber 4 is connected to an external air supply system through the air pressure pipe. A pressure gauge 6 is also fixedly connected to the air pressure cover plate 2, and the air pressure in the inflation chamber 4 is displayed by the pressure gauge 6. Multiple supports 34 are fixedly connected to the connector 3, with the length direction of the supports 34 arranged vertically, and the multiple supports 34 are spaced apart circumferentially along the connector 3. The air pressure cover plate 2 and the pressure frame 1 are supported on the ground by the supports 34.

[0043] refer to Figure 2 , Figure 3The joint 3 comprises a first connecting part 31, a second connecting part 32 and a third connecting part 33 in a ring shape, the first connecting part 31 and the second connecting part 32 are both at a certain angle with the third connecting part 33, and the first connecting part 31 and the second connecting part 32 are radially arranged with the surface of the third connecting part 33. The edge outside the first connecting part 31 and the edge outside the second connecting part 32 are both fixedly connected with the edge inside the third connecting part 33, so that the cross section of the joint 3 is Y-shaped. When the air pressure cover plate 2 is buckled with the pressure frame 1, the first connecting part 31 is located inside the inflation cavity 4, and the surface of the first connecting part 31 is attached to the inside surface of the air pressure cover plate 2; the second connecting part 32 is located inside the inflation cavity 4, and the surface of the second connecting part 32 is attached to the inside surface of the pressure frame 1; one end of the third connecting part 33 is located inside the inflation cavity 4, and the other end of the third connecting part 33 extends out of the inflation cavity 4 from the gap between the air pressure cover plate 2 and the pressure frame 1. The edge outside the third connecting part 33 is fixedly connected with a hinge 331, so that the air pressure cover plate 2, the pressure frame 1 and the joint 3 are hinged together. The first connecting part 31 is clamped with the air pressure cover plate 2, the second connecting part 32 is fixedly connected with the inside surface of the pressure frame 1 by bolts, and the fixed bolts are sealed by sealing glue.

[0044] Reference Figure 4 The edge of the air pressure cover plate 2 is provided with a clamping groove 21 for clamping the first connecting part 31 with the air pressure cover plate 2, and the clamping groove 21 is annular and arranged along the edge of the air pressure cover plate 2. Among the two side walls on both sides of the opening of the clamping groove 21, the end face of the outer side wall is fixedly connected with the edge of the air pressure cover plate 2, and the inner side wall is located inside the air pressure cover plate 2, and the opening of the clamping groove 21 faces the inside of the air pressure cover plate 2. The first connecting part 31 is fixedly connected with a clamping part 311 in the direction of the air pressure cover plate 2, and the clamping part 311 is concentrically annular with the first connecting part 31. The inner edge of the clamping part 311 is flush with the inner edge of the first connecting part 31, and the outer edge of the clamping part 311 is provided with a clamping groove 312, and the side wall of the clamping groove 312 matches the clamping groove 21, and the groove part of the clamping groove 312 matches the inner side wall of the clamping groove 21, so that the first connecting part 31 is clamped together by the mutual engagement of the clamping groove 21 and the clamping groove 312, thereby improving the connection stability between the first connecting part 31 and the air pressure cover plate 2.

[0045] The edge of the air pressure cover plate 2 is fixedly connected with a flange 22, the plate surface of the flange 22 is opposite to the opening of the air pressure cover plate 2, and the extension direction of the flange 22 is the same as the direction of the third connecting part 33. The surface of the third connecting part 33 is in close contact with the flange 22. A plurality of edge clamps 11 are detachably connected between the third connecting part 33 and the flange 22, and the third connecting part 33 and the flange 22 are clamped together through the edge clamps 11, thereby reducing the relative movement between the air pressure cover plate 2 and the joint 3 during the test.

[0046] Referring to Figure 1 , Figure 4 , the edge clamp 11 is a elastic clamping piece with a U-shaped cross section or a C-shaped clamp. When the air pressure cover plate 2 and the pressure frame 1 are buckled together, the edge clamp 11 clamps the air pressure cover plate 2 and the joint 3 on the inner side of the edge clamp 11 through its own elastic force.

[0047] Referring to Figure 4 , the joint 3, the air pressure cover plate 2 and the pressure frame 1 are clamped and fixed with a sealing layer 35. The sealing layer 35 includes a sealing gasket 351 and a sealing strip 352. The sealing layer 35 is located at the curved surface connection of the joint 3, and the sealing gasket 351 is located at the flat surface connection of the joint 3, thereby enhancing the sealing between the joint 3, the air pressure cover plate 2 and the pressure frame 1.

[0048] Referring to Figure 2 , Figure 5 , the composite material pressure frame 1 air pressure test device further comprises a sealing device 7 for plugging the wire hole on the pressure frame 1. The sealing device 7 comprises two oppositely arranged sealing plates 71, and the two sealing plates 71 are respectively located on the two sides of the pressure frame 1 and opposite to the wire hole. Among the two sealing plates 71, one sealing plate 71 is located on the A surface of the pressure frame 1 and is in close contact with the A surface of the pressure frame 1; the other sealing plate 71 is located on the B surface of the pressure frame 1 and is in close contact with the B surface of the pressure frame 1. The two sealing plates 71 are simultaneously threadedly connected with a connecting bolt 72, and the connecting bolt 72 simultaneously penetrates the two sealing plates 71 through the wire hole to fix the two sealing plates 71 and the pressure frame 1 together.

[0049] Referring to Figure 5 , the sealing ring 73 is arranged between the sealing plate 71 and the pressure frame 1, and the sealing ring 73 is fixedly connected with the sealing plate 71 and located on the inner side of the wire hole. When the sealing plate 71 approaches the connecting bolt 72 along the connecting bolt 72, the sealing plate 71 presses the sealing ring 73 and the pressure frame 1 tightly. When the inside of the inflation cavity 4 is in a positive pressure state, the sealing plate 71 located on the B surface of the pressure frame 1 presses the sealing plate 71 and the pressure frame 1 tightly through air pressure; when the inside of the inflation cavity 4 is in a negative pressure state, the sealing plate 71 located on the A surface of the pressure frame 1 presses the sealing plate 71 and the pressure frame 1 tightly through air pressure, thereby improving the air tightness of the inflation cavity 4.

[0050] A core layer 74 for increasing the strength of the sealing plate 71 is also arranged between the two sealing plates 71, and the core layer 74 is located in the air hole and arranged outside the connecting bolt 72. When the sealing plate 71 is pressed, the end surface of the sealing plate 71 abuts against the core layer 74, thereby reducing the deformation of the sealing plate 71 under pressure, and increasing the strength of the sealing plate 71.

[0051] The sealing plate 71 on the A surface of the pressure frame 1 is also bonded with a glue layer 75 for sealing between the pressure frame 1, and the glue layer 75 can adopt a sealing double-sided adhesive in the embodiment of the application, thereby further increasing the sealing between the sealing plate 71 and the pressure frame 1.

[0052] The embodiment of the application also discloses a composite material pressure frame air pressure experimental testing method, and the specific steps are as follows:

[0053] S1, assembly: the air pressure cover plate 2 is connected with the pressure frame 1 through the joint 3, and the joint 3 and the air pressure cover plate 2 are clamped through the edge clamping 11, and the air pressure cover plate 2 and the pressure frame 1 surrounding the sealed container are fixedly connected on the ground rail by using the support 34;

[0054] S2, pressure charging: high-pressure air is injected into the pressure cavity from the pressure charging pipeline by using a high-pressure air machine, when the pressure table 6 reaches a predetermined pressure, the pressure charging amount is reduced; after a period of time, when the temperature and air pressure are stable and reach the specified temperature of the test, the pressure charging is stopped, and the pressure and temperature in the air charging cavity 4 satisfy the following relationship:

[0055]

[0056] In the formula, p1 is the air pressure before the container is charged, T1 is the room temperature, p2 is the air pressure after the container is charged, T2 is the temperature, k is the adiabatic coefficient, after the air charging is completed, the air bottle pressure also decreases through the thin wall surface heat dissipation, that is,

[0057]

[0058] In the formula, p3 is the actual working pressure in the container, that is, the actual air charging pressure is:

[0059] p2=k p3-p1 (k-1) (3)

[0060] The pressure on the wall surface in the container is uniformly distributed, or expands outward, or shrinks inward. Since the test device is symmetrical, there is only normal stress on the cross section:

[0061]

[0062] In the formula, p is the maximum pressure in the pressure charging process, is the thin film stress, R is the air pressure frame radius, and t is the shell thickness of the air pressure cover plate 2.

[0063] According to the maximum stress criterion of the material:

[0064]

[0065] Therefore, the cover plate wall thickness can be calculated by the shell theory as follows:

[0066]

[0067] In the formula, n is the minimum safety factor.

[0068] When the pressure gauge 6 exceeds a certain range of the preset value, the safety valve is opened to release the air; after reaching the static time, the strain gauge displacement of the pressure frame 1 is measured, and the air tightness of the device is detected by the super-equipment and other methods;

[0069] S3, pressure relief: after reaching the pressure maintaining time, the high pressure air between the air pressure cover plate 2 and the pressure frame 1 is discharged by an external device until the normal pressure state;

[0070] S4, negative pressure: the air in the inflation cavity 4 is pumped out by a vacuum pump to make the inflation cavity 4 in a negative pressure state, and the method in S2 is used for detection;

[0071] S5, secondary pressure relief and cover opening inspection: the air pressure in the inflation cavity 4 is adjusted to the normal pressure, the sealing edge clamp 11 is disassembled, the air pressure cover plate 2 is rotated and opened by the hinge 331 to expose the inside of the pressure frame 1, so as to check and detect; if the damage tolerance test is performed, the impact damage can be introduced.

[0072] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A composite pressure frame pneumatic test device, characterized in that: Includes a pneumatic cover plate (2), a connector (3) for connecting the pneumatic cover plate (2) and the pressure frame (1), when the pneumatic cover plate (2) and the pressure frame (1) are fastened together, the connector (3) is located between the pneumatic cover plate (2) and the pressure frame (1) and is hinged together by a hinge (331), and the pneumatic cover plate (2) and the pressure frame (1) are fixed together by the connector (3) and form a hollow, sealed space inside, a pressurized pipe inside the pneumatic cover plate (2) and a pressure gauge (6) for detecting the pressure between the pneumatic cover plate (2) and the pressure frame (1); The connector (3) is annular and includes a first connecting part (31), a second connecting part (32) and a third connecting part (33) in annular shape. The first connecting part (31) and the second connecting part (32) are mirror images of the plate surface of the third connecting part (33). The outer edge of the first connecting part (31), the outer edge of the second connecting part (32) and the inner edge of the third connecting part (33) are fixed together. The first connecting part (31) is attached to the inner side wall of the air pressure cover plate (2). The second connecting part (32) is attached to the inner side wall of the pressure frame (1) and fixed together by bolts. The third connecting part (33) extends out from between the air pressure cover plate (2) and the pressure frame (1). The edge of the air pressure cover plate (2) is provided with a flange (22), the third connecting part (33) is attached to the flange (22), and a plurality of edge-sealing clips (11) are provided between the flange (22) and the third connecting part (33) to hold the flange (22) and the third connecting part (33) together.

2. The composite pressure frame gas pressure test apparatus of claim 1, wherein: The edge of the air pressure cover plate (2) is provided with a snap-fit ​​groove (21), and the first connecting part (31) is provided with a snap-fit ​​part (311). The air pressure cover plate (2) and the first connecting part (31) are snapped together by the snap-fit ​​groove (21) and the snap-fit ​​part (311).

3. The composite pressure frame gas pressure test apparatus of claim 1, wherein: A sealing strip (352) is provided between the connector (3) and the air pressure cover plate (2) and between the connector (3) and the pressure frame (1).

4. The composite pressure frame gas pressure test apparatus of claim 1, wherein: The device includes a sealing device (7) for sealing the through hole on the pressure frame (1). The sealing device (7) includes two opposing sealing plates (71) and a connecting bolt (72). One of the two sealing plates (71) is in contact with the A side of the pressure frame (1), and the other sealing plate (71) is in contact with the B side of the pressure frame (1). The two sealing plates (71) are pressed together with the pressure frame (1) by the connecting bolt (72).

5. The composite material pressure frame air pressure test device according to claim 4, characterized in that: The sealing device (7) also includes a core layer (74) for supporting the two sealing plates (71).

6. The composite material pressure frame air pressure test device according to claim 5, characterized in that: A sealing ring (73) is provided between the sealing plate (71) and the pressure frame (1).

7. The composite material pressure frame air pressure test device according to claim 6, characterized in that: A sealing adhesive layer (75) is provided between the sealing plate (71) and the A side of the pressure frame (1).

8. A testing method using the composite material pressure frame pneumatic test apparatus according to any one of claims 1-7, characterized in that, The specific steps are as follows: S1. Assembly: Connect the air pressure cover plate (2) to the pressure frame (1) through the connector (3), and clamp the connector (3) to the air pressure cover plate (2) through the sealing clamp (11); S2. Pressurization: Pressurize the air pressure cover plate (2) to the required value through the pressurization pipe, and perform an airtightness test after standing; S3. Depressurization: Discharge the high-pressure air between the air pressure cover plate (2) and the pressure frame (1) until the normal pressure state; S4. Negative pressure: Reduce the air pressure between the air pressure cover plate (2) and the pressure frame (1) to the required value through the pressurization pipe, and perform an airtightness test after standing; S5. Secondary depressurization and opening inspection: Adjust the air pressure cover plate (2) and the pressure frame (1) to normal pressure, remove the sealing clamp (11) and open the air pressure cover plate (2), and inspect the pressure frame (1).

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