Composite connection loading method for high-load static test of wave suppression plate of seaplane

Abstract

The invention relates to the field of airplane structure static strength analysis, and particularly provides a composite connection loading method for a seaplane wave suppression plate high-load static test. The method comprises the following steps: step 1, preliminarily determining an adhesive tape distribution position based on the height gradient of a wave suppression plate and a single adhesive tape action area; 2, according to the force transmission characteristic that the load at the front end of the wave suppression plate structure is obviously higher than that at the rear end, the test load is simplified to a stringer-frame connection node of the wave suppression plate, and the arrangement position of the adhesive tape is finally determined by integrating the step 1; 3, connecting fasteners of the stringer-frame are dismantled in the adhesive tape acting area so that prefabricated holes can be vacated, and connecting bolts are installed at the positions of the prefabricated holes; 4, the adhesive tape is mechanically fixed to the wave suppression plate through the connecting bolts, the adhesive tape is bonded to the surface of the wave suppression plate synchronously, and a composite connecting interface is formed; 5, the adhesive tape is connected to an actuator cylinder through a steel cable; and step 6, loading according to a preset load spectrum. The adhesive tape has the advantages of high adhesive tape bearing capacity, simplicity and convenience in operation and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aircraft structure static strength analysis method, and particularly relates to a composite connecting loading method for high-load static test of a seaplane wave suppression plate. BACKGROUND

[0002] As a key special structural part of a seaplane, the wave suppression plate is installed on the outside of the wave suppression groove of the ship bottom, and its core function is to change the transverse splashing water flow into longitudinal flow, thereby significantly improving the splashing performance. This function is crucial to avoid the impact of splashing water flow on the engine, flap structure and the pilot's vision. Once the wave suppression plate fails, the fuselage will directly bear the impact of the water flow when the aircraft is running in the water, causing the ship bottom structure to bear abnormal water load, and in severe cases, the water flow may even splash to the flap or windshield, posing a major flight safety hazard. Therefore, it is of great engineering significance to establish a complete and efficient static test method for the wave suppression plate and accurately check its structural static strength.

[0003] Currently, there are relatively few static tests on the wave suppression plate at home and abroad. Most studies mainly rely on detailed finite element analysis (FEA) for strength evaluation, however, due to the lack of sufficient static test data verification, the accuracy of such analysis methods is difficult to effectively improve and confirm. The particularity of the wave suppression plate structure itself further aggravates the difficulty of static test: the load borne by the front end area is much higher than that by the rear end, but the space of the front end area is extremely cramped (the maximum height of the wave suppression plate involved in the present application is 950mm, and the minimum height is only 400mm). The conventional loading adhesive tape is large in size (typical size is 210mm x 180mm), and is only glued to the surface of the wave suppression plate, and due to its low bearing capacity (about 3500N), the maintenance cost is high, and it is difficult to effectively apply the required high load on such a small and special-shaped curved surface structure. Therefore, the conventional static test method is limited by the insufficient connection strength of the adhesive tape, which becomes the main bottleneck restricting the test.

[0004] In addition, the detailed finite element analysis method has inherent limitations such as high uncertainty and difficulty in verification in the strength evaluation of the wave suppression plate, and it is necessary to carry out targeted static test. SUMMARY

[0005] The purpose of the present application is to provide a composite connecting loading method for high-load static test of a seaplane wave suppression plate. The present application has the advantages of high bearing capacity of the adhesive tape, simple operation, etc., and can effectively solve the implementation problem of the static test of the wave suppression plate.

[0006] The technical solution of the present application is: a composite connecting loading method for high-load static test of a seaplane wave suppression plate, comprising the following steps: Step 1: Based on the height gradient of the wave suppression plate and the action area of the single piece of adhesive tape, the distribution position of the adhesive tape is preliminarily determined; Step 2: According to the load transfer characteristics that the front end load of the wave suppression plate structure is significantly higher than the rear end, the test load is simplified to the stringer-frame connection node of the wave suppression plate, and the adhesive tape arrangement position is finally confirmed in combination with step 1; Step 3: The connecting fasteners of the stringer-frame in the action area of the adhesive tape are removed to leave preformed holes, and connecting bolts are installed at the positions of the preformed holes; Step 4: The adhesive tape is mechanically fixed to the wave suppression plate through the connecting bolts, and the adhesive tape is simultaneously glued to the surface of the wave suppression plate to form a composite connection interface; Step 5: The adhesive tape is connected to the actuator cylinder through a steel cable; Step 6: The loading is performed according to the preset load spectrum.

[0007] In the composite connection loading method for the high-load static test of the seaplane wave suppression plate, in step 2, the adhesive tape is preferentially arranged at the frame structure position in view of the spatial constraint of the front end of the wave suppression plate.

[0008] In the composite connection loading method for the high-load static test of the seaplane wave suppression plate, in step 2, the number of connecting bolts for connecting the adhesive tape at the front end of the wave suppression plate is higher than the number of connecting bolts for connecting the adhesive tape at the rear end of the wave suppression plate.

[0009] In the composite connection loading method for the high-load static test of the seaplane wave suppression plate, in step 3, the nominal diameter of the connecting bolt is Φ=3.97mm, and the length is 12.7mm.

[0010] In the composite connection loading method for the high-load static test of the seaplane wave suppression plate, in step 4, the installation direction of the connecting bolt is towards the outside of the fuselage, and the nut is fixed to the outside of the adhesive tape.

[0011] In the composite connection loading method for the high-load static test of the seaplane wave suppression plate, in step 4, the distance from the center of the connecting bolt to the boundary of the adhesive tape is not less than 2 times the diameter of the bolt.

[0012] In the composite connection loading method for the high-load static test of the seaplane wave suppression plate, in step 1, the standard action area of the single piece of adhesive tape 8 is 210mm×180mm.

[0013] In the composite connection loading method for the high-load static test of the seaplane wave suppression plate, in step 1, the height gradient of the wave suppression plate is 400mm from the front end area with the largest load to the rear end area with 950mm.

[0014] The advantages of the present application are: for the special-shaped curved surface geometry characteristics and the high load characteristics borne by the seaplane wave plate, the conventional static test method is difficult to effectively implement, the present application replaces the existing fastener on the wave plate with a special connecting bolt, and uses the bolt and the cement composite to fix the loading adhesive tape, realizes the static test of the wave plate. The test technology enhances the load transmission capacity and the bearing limit of the adhesive tape, successfully solves the technical problems of efficiently applying high load in the special-shaped curved surface and small space. The method has simple structure, clear operation process and convenient operation, effectively overcomes the key difficulties of the wave plate static test, significantly reduces the test implementation difficulty, improves the work efficiency, and provides reliable guarantee for the static strength verification of the seaplane wave plate.

[0015] By successfully implementing the static test in the whole machine state, the present application not only realizes the static strength verification of the wave plate under the large load condition, but more importantly, provides a valuable test verification means for the detail finite element analysis method, which effectively improves the accuracy and reliability of the wave plate static strength checking, and finally lays a solid foundation for shortening the aircraft development cycle and reducing the development cost.

[0016] In summary, for the pain points of the conventional static test of the wave plate, the present application provides a simple and feasible solution: Convenient and efficient operation: the method steps are clear, the existing fastener preformed hole of the wave plate is used to install the detachable connecting bolt, which significantly simplifies the test process and reduces the time cost and economic cost.

[0017] Breakthrough space load limit and improve the carrying capacity of the adhesive tape: the core is the innovative bolt-cement composite connection technology, which greatly improves the carrying capacity and load transmission efficiency of the adhesive tape in small space (especially special-shaped curved surface), and successfully solves the key problem of applying high test load in the small space of the wave plate with high load gradient (especially the front end).

[0018] Wide application range: the method is especially suitable for static test of complex structures with large load and small space constraints, which not only meets the specific test requirements of the wave plate, but also provides a complete static strength checking verification means.

[0019] High verification value: the successful implementation of the wave plate static test provides valuable test data support for the detail finite element analysis (FEA) method, effectively improves the accuracy and reliability of the static strength analysis of the wave plate.

[0020] High reliability of test results: through static test verification of a large fire-fighting amphibious aircraft wave plate, the test results show that 92.45% of the test data is consistent with the theoretical data, the strain measurement value of the front wave plate is less than or equal to 9% of the finite element prediction, which fully meets the structural deformation limit requirements of CCAR-25-R4 airworthiness provisions, see Table 1. Key, the bolt-cement composite connection interface does not appear to peel off under 100% limit load, the carrying capacity of the adhesive tape is increased to 5000N (increased by 42.8% compared with the conventional 3500N), and the loading problem of the special-shaped curved narrow space (400mm height area) is completely solved. The test data provides high confidence input for the correction of the wave plate detail finite element model, greatly shortening the strength checking period.

[0021] Table 1 Comparison of typical test data and theoretical data of the front end of the wave plate

[0022] Method universality: provides a simple, efficient and accurate verification idea for the static test of the special structure of the seaplane (such as the wave plate), which has important engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A wave plate structure diagram is provided for the present application; Figure 2 A connecting bolt-cement composite connection adhesive tape structure diagram is provided for the present application; Figure 3 A static test site diagram of the wave plate is provided for the present application.

[0024] Wherein 1 is the front wave plate, 2 is the front and middle connecting wave plate, 3 is the middle wave plate, 4 is the middle and rear connecting wave plate, 5 is the rear wave plate, 6 is the connecting bolt, 7 is the wave plate outer skin, and 8 is the adhesive tape. DETAILED DESCRIPTION

[0025] In order to better understand the function and purpose of the present application, and not be regarded as a restrictive solution, the following based on the drawings make further detailed description of the embodiments of the present application.

[0026] In the drawings, the same or similar reference numbers represent the same or similar elements or elements with the same or similar functions throughout. The described embodiments are part of the embodiments of the present application, not all embodiments, and the parts not described in detail are conventional techniques. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0027] Example 1. The present application is a composite connection loading method for high load static test of seaplane wave plate, see Figures 1-3, the structure of the wave suppression plate refers to Figure 1 , and the wave suppression plates are installed on the wave suppression plate outer skin 7 through fasteners, and the loading method is as follows: Step 1: Adhesive tape planning under spatial constraints: Based on the narrow space and significant height gradient (transitioning from 400mm at the front end area (front end wave suppression plate 1) with the largest load to 950mm at the rear end area (rear end wave suppression plate 5)), combined with the standard action area (210mm x 180mm) of a single adhesive tape 8, topological optimization is performed in the three-dimensional irregular curved surface space to preliminarily plan the adhesive tape distribution position, ensuring that the load transmission path covers the key stress nodes. Step 2: Load equivalence and position confirmation: According to the force transmission characteristics of the wave suppression plate (the front end water dynamic load can reach more than 3 times the rear end), the test load is simplified to the stringer-frame connection node according to the static equivalence principle. Based on the planning of step 1, the final coordinates of the adhesive tape 8 are confirmed, wherein: the high load area at the front end is preferentially arranged at the frame structure position; the number of bolts is dynamically configured (front end > rear end) to match the load gradient. Supplementary note 1: The space at the front end of the wave suppression plate is particularly urgent, and the adhesive tape can be preferentially arranged at the frame structure position. Supplementary note 2: In order to match the high load characteristics at the front end, the number of connecting bolts can be increased in the front end area (or the bolt configuration can be optimized according to the specific load distribution).

[0028] Step 3: Preparation of composite connection matrix: Remove the original fasteners (brand MS2047AD5-7) of the stringer-frame connection in the target area; implant 16 special connecting bolts 6 (Φ=3.97mm precisely match the pre-made hole, L=12.7mm > original fastener length 11.13mm, bolt length increment provides space for glue layer thickness and assembly tolerance).

[0029] Step 4: Bolt-glue composite connection: Lay adhesive tape 8 covering the bolt array; install nuts on the outside of the adhesive tape (towards the outside of the fuselage), realizing detachable fixation; simultaneously apply aviation-grade epoxy adhesive (brand FN305), forming a mechanical-chemical composite interface after curing; the center-to-center distance of the bolts to the edge of the adhesive tape is strictly kept at 8mm (=2x3.97mm bolt diameter, meeting the minimum boundary requirement).

[0030] Installation specification: The installation direction of the connecting bolts should be towards the outside of the fuselage (i.e. the nuts are located on the outside of the adhesive tape), to facilitate disassembly and adjustment.

[0031] Boundary requirement: The minimum distance from the center of the connecting bolt to the edge of the adhesive tape should be no less than 2 times the bolt diameter.

[0032] Step 5: Load transmission system construction: According to the adhesive tape 8→steel cable→hydraulic actuator, a closed-loop load transmission chain is constructed.

[0033] Step 6: Gradient load test: Loading is performed in stages according to preset working conditions: 30% design load → system pre-tightening check; 80% design load → connection interface integrity verification; 100%-150% design load → ultimate strength test.

[0034] The above description represents possible embodiments of the present invention, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A composite connection loading method for high-load static testing of wave-damping plates for seaplanes, characterized in that, Includes the following steps: Step 1: Based on the height gradient of the wave suppression plate and the effective area of ​​a single piece of adhesive tape, the distribution position of the adhesive tape is initially determined; Step 2: Based on the force transmission characteristics that the load at the front end of the wave-damping plate structure is significantly higher than that at the rear end, the test load is simplified to the long string-frame connection node of the wave-damping plate. The final position of the adhesive tape arrangement is confirmed by combining Step 1. Step 3: Remove the connecting fasteners of the truss-frame in the area where the tape is applied to create a pre-drilled hole, and install the connecting bolts at the pre-drilled hole location; Step 4: Mechanically fix the adhesive tape to the wave-suppressing plate using connecting bolts, and simultaneously glue the adhesive tape to the surface of the wave-suppressing plate to form a composite connection interface; Step 5: Connect the adhesive tape to the actuator cylinder via a steel cable; Step 6: Load according to the preset load spectrum.

2. The composite connection loading method for high-load static testing of seaplane wave-damping plates according to claim 1, characterized in that: In step 2, given the spatial constraints at the front end of the wave suppressor, the adhesive tape is preferentially placed at the frame structure position.

3. The composite connection loading method for high-load static testing of seaplane wave-damping plates according to claim 1, characterized in that: In step 2, the number of connecting bolts for the adhesive tape at the front end of the wave suppressor is higher than the number of connecting bolts for the adhesive tape at the rear end of the wave suppressor.

4. The composite connection loading method for high-load static testing of seaplane wave-damping plates according to claim 1, characterized in that: In step 3, the nominal diameter of the connecting bolt is Φ=3.97mm and the length is 12.7mm.

5. The composite connection loading method for high-load static testing of seaplane wave-damping plates according to claim 1, characterized in that: In step 4, the connecting bolts are installed facing outwards from the machine body, and the nuts are fixed to the outside of the tape.

6. The composite connection loading method for high-load static testing of seaplane wave-damping plates according to claim 1, characterized in that: In step 4, the distance from the center of the connecting bolt to the boundary of the adhesive tape is not less than twice the bolt diameter.

7. The composite connection loading method for high-load static testing of seaplane wave-damping plates according to claim 1, characterized in that: In step 1, the standard working area of ​​a single piece of adhesive tape 8 is 210mm × 180mm.

8. The composite connection loading method for high-load static testing of seaplane wave-damping plates according to claim 1, characterized in that: In step 1, the height gradient of the wave suppressor is: from 400mm in the front end area where the load is greatest to 950mm in the rear end area.

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