Machine plate fastener clearance fit sealing performance evaluation method

Abstract

The invention provides a method for evaluating the clearance fit sealing performance of a plate fastener for a machine. The method comprises the following steps of initial leakage rate detection, air pressure loading test, leakage state detection after helium stamping, data analysis and evaluation and formation of the evaluation method. The leakage state of the aircraft composite fuselage fastener screw hole can be accurately recognized and positioned through an efficient method, and it is ensured that the sealing performance is accurately evaluated. The method is rapid and reliable, can comprehensively detect the sealing effect of the aircraft plate in the service state, verifies whether the aircraft plate meets the design requirements or not, and timely identifies potential weaknesses, thereby enhancing the safety and reliability of an aircraft. Meanwhile, the method can also verify the stability of the sealing performance of the screw hole under the continuous barometric load, and ensures the safe service of an airplane.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft wall panels, in particular to a method for evaluating the clearance fit sealing of a machine plate fastener. Background Art

[0002] The sealing test of the clearance fit of the fasteners of the aircraft fuselage wall panel is an indispensable part of the aircraft ground test. Its core value lies in verifying the assembly process of the fuselage wall panel and providing the design team with the data support required to optimize the aircraft structure. In order to ensure the accurate evaluation of the leakage status of the screw holes of the aircraft fuselage wall panel fasteners and truly simulate the sealing performance of the clearance fit of the fasteners after loading, we first need to conduct a comprehensive test on the clearance fit sealing of all fasteners on the fuselage wall panel. Next, by loading the overall structure of the fuselage wall panel and monitoring its sealing leakage status in real time, we can have a more comprehensive understanding of the sealing performance. Finally, we accurately locate the leakage status of a single screw hole in the fuselage wall panel and use the leakage rate data to evaluate the sealing performance of the fastener assembly process. Although the commonly used sealing evaluation methods include pressure decay method, ultrasonic detection method and infrared thermal imaging method, these methods have limitations in some aspects, such as the difficulty in identifying small leakage rates, the inaccurate positioning of leakage points, and the susceptibility of detection equipment to the external environment. Summary of the invention

[0003] In order to solve the problems of the prior art, the present invention provides a method for evaluating the clearance fit and sealing performance of machine plate fasteners, which can achieve accurate evaluation of the clearance fit and sealing performance of machine plate fasteners, and can more accurately understand the sealing status of machine plate fasteners, providing strong support for aircraft design and maintenance.

[0004] A method for evaluating the clearance fit and sealing performance of a machine-used plate fastener comprises the following steps: 1) Initial leakage rate detection: Use a helium leak detector to detect the leakage rate at all screw holes after the machine plate is assembled, and record the initial leakage rate data of each screw hole in detail to verify the leakage status of the fastener clearance fit before loading; 2) Air pressure loading test: Under the condition of ensuring good sealing of the gap fit of the machine plate fasteners, the air pressure loading test is carried out to simulate the actual service status of the aircraft fuselage wall panel, and helium stamping is continued for 24 hours, during which the pressure drop changes of the overall structure are monitored in real time; 3) Leakage status detection after helium stamping: After the helium stamping is completed, the helium leak detector is used again to detect the leakage status of all screw holes of the machine plate, and the test data is compared and analyzed with the test data before helium stamping, and the leakage rate changes of each screw hole are accurately recorded; 4) Data analysis and evaluation: By comparing the test data before and after helium stamping and the pressure drop change of the overall structure during helium stamping, the leakage amount and position of different screw holes are evaluated; 5) Form an evaluation method: Based on the overall pressure drop change and the leakage rate change of a single screw hole, a set of machine plate fastener clearance fit sealing evaluation methods is formed, thereby effectively testing the sealing performance of aircraft composite fuselage fastener clearance fit.

[0005] As a further improvement, during the air pressure loading test in step 2), the air pressure load is gradually applied, and at the same time, the deformation of the fuselage panel, the dynamic changes of the fastener gap, and the potential leakage points are accurately recorded.

[0006] For further improvement, the specific process of step 4) is as follows: conduct an in-depth comparison of the helium leak detector test data before and after helium stamping, and combine the pressure drop change data of the overall structure during the helium stamping process to evaluate the potential impact of different screw hole gaps and wet installation methods on the leakage amount. At the same time, analyze the leakage phenomenon and specific location of the screw holes of the machine plate, so as to accurately identify whether there is a sealing problem.

[0007] In step 5), the method for evaluating the gap fit and sealing performance of machine plate fasteners is further improved based on the data obtained from steps 1) to 4), and an evaluation report on the gap fit and sealing performance of machine plate fasteners is compiled, covering the initial leakage rate data, the pressure drop change during the helium stamping process, and the leakage rate re-inspection data after helium stamping, and specific analysis and solution suggestions are proposed for the existing problems.

[0008] The beneficial effect of the present invention is that the leakage state of the screw holes of the aircraft composite fuselage fasteners can be accurately identified and located by an efficient method, ensuring accurate evaluation of the sealing performance. This method is not only fast and reliable, but also can comprehensively detect the sealing effect of the machine plate in the service state, verify whether it meets the design requirements, and identify potential weaknesses in time, thereby enhancing the safety and reliability of the aircraft. At the same time, the method can also verify the stability of the sealing performance of the screw holes under continuous air pressure loads to ensure the safe service of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 It is a schematic diagram of the helium mass spectrometer air tightness detection of the present invention. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] The detection method provided by the present invention is as follows Figure 1 As shown, the specific steps include: Step 1: First, use a helium leak detector to perform a detailed leak rate test on all screw holes of the machine plate after assembly. This is to accurately evaluate the sealing status of the fastener clearance fit before loading, and record the initial leak rate data of each screw hole in detail to provide a benchmark parameter for subsequent analysis.

[0013] Step 2: After ensuring that the airtightness of the gap between the fasteners of the aircraft sheet meets the standard, use the airtight test tooling to perform a systematic air pressure loading test on the overall structure of the fuselage panel. During the test, the air pressure load is gradually applied, while accurately recording the deformation of the fuselage panel, the dynamic changes in the fastener gap, and potential leakage points. The entire test process simulates the actual service environment of the aircraft fuselage panel to ensure real-time monitoring of the pressure drop changes of the overall structure.

[0014] Step 3: After completing the helium stamping stage, use the helium leak detector to perform a secondary leakage status test on all screw holes. By comparing and analyzing the test data before and after helium stamping, the leakage rate changes of each screw hole are accurately recorded to provide data support for subsequent in-depth analysis.

[0015] Step 4: Conduct an in-depth comparison of the helium leak detector test data before and after helium stamping, and combine the pressure drop change data of the overall structure during helium stamping to systematically evaluate the potential impact of different screw hole gaps and wet installation methods on leakage. At the same time, carefully analyze the leakage phenomenon and specific location of the screw holes of the machine plate to accurately identify possible sealing problems.

[0016] Step 5: Based on the above comprehensive and in-depth data analysis, prepare an evaluation report on the gap fit sealing performance of machine-used sheet metal fasteners. The report will cover in detail the initial leakage rate data, the pressure drop change during the helium stamping process, the leakage rate re-inspection data after helium stamping, and propose specific analysis and solution suggestions for existing problems.

[0017] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, the above is only a preferred embodiment of the present invention. Since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field is within the technical scope disclosed by the present invention. For ordinary technicians in the technical field, changes or replacements that can be easily thought of should be covered within the protection scope of the present invention without departing from the principle of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for evaluating the clearance fit and sealing performance of a machine-used sheet metal fastener, characterized in that The following steps are involved: 1) Initial leakage rate detection: Use a helium leak detector to detect the leakage rate at all screw holes after the machine plate is assembled, and record the initial leakage rate data of each screw hole in detail to verify the leakage status of the fastener clearance fit before loading; 2) Air pressure loading test: Under the condition of ensuring good sealing of the gap fit of the machine plate fasteners, the air pressure loading test is carried out to simulate the actual service status of the aircraft fuselage wall panel, and helium stamping is continued for 24 hours, during which the pressure drop changes of the overall structure are monitored in real time; 3) Leakage status detection after helium stamping: After the helium stamping is completed, the helium leak detector is used again to detect the leakage status of all screw holes of the machine plate, and the test data is compared and analyzed with the test data before helium stamping, and the leakage rate changes of each screw hole are accurately recorded; 4) Data analysis and evaluation: By comparing the test data before and after helium stamping and the pressure drop change of the overall structure during helium stamping, the leakage amount and position of different screw holes are evaluated; 5) Form an evaluation method: Based on the overall pressure drop change and the leakage rate change of a single screw hole, a set of machine plate fastener clearance fit sealing evaluation methods is formed, thereby effectively testing the sealing performance of aircraft composite fuselage fastener clearance fit.

2. The method for evaluating the clearance fit and sealing performance of a machine plate fastener according to claim 1, characterized in that: During the air pressure loading test in step 2), the air pressure load is gradually applied while accurately recording the deformation of the fuselage panel, the dynamic changes of the fastener gap, and the potential leakage points.

3. The method for evaluating the clearance fit and sealing performance of a sheet metal fastener for a machine according to claim 1, characterized in that: Step 4) The specific process is as follows: conduct an in-depth comparison of the helium leak detector test data before and after helium stamping, and combine the pressure drop change data of the overall structure during the helium stamping process to evaluate the potential impact of different screw hole gaps and wet installation methods on the leakage amount. At the same time, analyze the leakage phenomenon and its specific location at the screw holes of the machine plate, so as to accurately identify whether there is a sealing problem.

4. The method for evaluating the clearance fit and sealing performance of a machine plate fastener according to claim 1, characterized in that: In the method for evaluating the gap fit and sealing performance of machine plate fasteners described in step 5), based on the data obtained from steps 1) to 4), an evaluation report on the gap fit and sealing performance of machine plate fasteners is prepared, covering the initial leakage rate data, the pressure drop change during the helium stamping process, and the leakage rate re-inspection data after helium stamping, and specific analysis and solution suggestions are proposed for the existing problems.

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