An in-plane pre-stress loading vibration fatigue test system for an aircraft panel structure

Abstract

This application belongs to the technical field of vibration fatigue test design for aircraft panel structures, specifically relating to an in-plane prestressed loading vibration fatigue test system for aircraft panel structures. The system includes a vibration support fixture and a prestressed loading fixture connected to the panel structure. The prestressed loading fixture is used to apply in-plane prestress to the panel structure, including tensile prestress and compressive prestress. The vibration support fixture is used to support the panel structure, the prestressed loading fixture, and to connect to a vibration table for vibration loading of the panel structure.

Description

Technical Field

[0001] This application belongs to the technical field of vibration fatigue test design for aircraft panel structures, specifically relating to an in-plane prestressed loading vibration fatigue test system for aircraft panel structures. Background Technology

[0002] Panel structures are distributed across the fuselage, wings, and fairings of aircraft, serving as key components that define the aircraft's external aerodynamic shape and internal load-bearing structure, thus accounting for a significant portion of the aircraft's structure. During flight, due to factors such as turbulent airflow and engine rotor imbalance, panel structures endure severe vibration loads, and vibration fatigue failure frequently occurs. Therefore, it is essential to conduct vibration fatigue tests on panel structures.

[0003] Vibration fatigue testing of panel structures typically involves taking panels from an aircraft or designing identical panels, designing fixed support fixtures, and conducting the test on a vibration table. However, as the panel structure is part of the overall aircraft structure, the in-plane prestress generated during its installation on the aircraft is often ignored in vibration fatigue testing. Yet, in-plane prestress has a significant impact on the modal characteristics of the panel structure, and ignoring it reduces the authenticity and reliability of the vibration fatigue test.

[0004] Currently, in vibration fatigue tests of wall panel structures, in-plane prestress is mostly applied using actuators or rubber ropes. Applying in-plane prestress to wall panel structures using actuators is complex in terms of loading system and method, costly, requires large installation space, and has low testing efficiency, making it unsuitable for wall panel structures. Applying in-plane prestress to wall panel structures using rubber ropes can only apply tensile prestress, and the deformation of the rubber rope must be considered. The test system is also very large, and similarly suffers from low testing efficiency, failing to effectively apply prestress to the wall panel structure.

[0005] This application is made in view of the aforementioned technical deficiencies. Summary of the Invention

[0006] The purpose of this application is to provide a vibration fatigue testing system for in-plane prestressing of aircraft panel structures, which can apply in-plane prestress in the vibration fatigue test of aircraft panel structures to simulate the actual installation and working environment of the panel structure on the aircraft, and ensure the effectiveness of the vibration fatigue test.

[0007] The technical solution of this application is:

[0008] A vibration fatigue testing system for in-plane prestressed loading of aircraft panel structure includes a vibration support fixture and a prestressed loading fixture;

[0009] Vibration support fixtures include a base plate and a support base;

[0010] The base plate is used to connect to the vibration table;

[0011] There are two support seats that are slidably connected to the base plate. The two support seats are used to connect to two stiffeners of the wall panel structure, which are located below the skin of the wall panel structure.

[0012] The prestressed loading fixture includes a slide, force sensor, connecting joint, connecting plate, connecting block, screw, and loading cylinder;

[0013] There are two slides, arranged opposite to each other, and slidably connected to the base plate;

[0014] There are two force sensors, connected to the slide.

[0015] There are two connectors, which connect to two force sensors;

[0016] There are two connecting plates, one edge of which is hinged to two connecting joints, and the other edge is used to connect to the edges of the skin on both sides of the wall panel structure.

[0017] There are two connecting blocks, which are connected to the slide.

[0018] There are two screws with opposite threads, and one end is threaded to two connecting blocks.

[0019] The loading cylinder is threaded at both ends to the other end of the two screws.

[0020] According to at least one embodiment of this application, in the above-described aircraft panel structure in-plane prestressed loading vibration fatigue test system, the base plate is rectangular and is connected to the vibration table by screws.

[0021] Two support bases are connected to the base plate by screws, and the corresponding screw holes on the support bases are strip-shaped holes;

[0022] Two support bases are arranged axially along the base plate, and strip holes on them extend axially along the base plate.

[0023] The two support bases have strip-shaped connecting protrusions, which are stepped and connected to the ribs at the top by screws.

[0024] According to at least one embodiment of this application, in the above-mentioned aircraft panel structure in-plane prestressed loading vibration fatigue test system, the slide block is slidably connected to the dovetail-shaped groove opened on the base plate through a dovetail-shaped protrusion.

[0025] The slide is connected to the base plate by screws, and the corresponding screw holes on the slide are strip-shaped holes.

[0026] According to at least one embodiment of this application, in the above-mentioned aircraft panel structure in-plane prestressed loading vibration fatigue test system, the slide is an L-shaped plate, and angular support ribs are provided between its horizontal plate and vertical plate.

[0027] The swallowtail-shaped protrusion is located at the bottom of the horizontal plate.

[0028] According to at least one embodiment of this application, in the above-described aircraft panel structure in-plane prestressed loading vibration fatigue test system, two force sensors are connected to the vertical plate of the slide by screws.

[0029] According to at least one embodiment of this application, in the above-described aircraft panel structure in-plane prestressed loading vibration fatigue test system, two connecting blocks are connected to the vertical plate of the slide by screws and are located above the force sensor.

[0030] According to at least one embodiment of this application, in the above-described aircraft panel structure in-plane prestressed loading vibration fatigue test system, two connecting joints are threadedly connected to two force sensors.

[0031] According to at least one embodiment of this application, in the above-described aircraft panel structure in-plane prestressed loading vibration fatigue test system, two connecting plates are hinged to a double-ear structure provided on the connecting joint by pins, and the edge of the connecting plate and the connecting joint is arc-shaped.

[0032] According to at least one embodiment of this application, in the above-described aircraft panel structure in-plane prestressed loading vibration fatigue test system, the connecting plate is connected to the edge of the skin by pins.

[0033] According to at least one embodiment of this application, in the above-described aircraft panel structure in-plane prestressed loading vibration fatigue test system, the outer wall of the loading cylinder is hexagonal. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the wall panel structure provided in the embodiments of this application;

[0035] Figure 2 This is a schematic diagram of the operation of the in-plane prestressed loading vibration fatigue test system for aircraft panel structures provided in this application embodiment;

[0036] Figure 3 This is a schematic diagram of the vibration support fixture provided in an embodiment of this application;

[0037] Figure 4 This is a schematic diagram of the base plate provided in an embodiment of this application;

[0038] Figure 5 This is a schematic diagram of the support base provided in an embodiment of this application;

[0039] Figure 6 This is a schematic diagram of the prestressed loading fixture provided in the embodiments of this application;

[0040] Figure 7This is a schematic diagram of the slide provided in an embodiment of this application;

[0041] Figure 8 This is a schematic diagram of the force sensing provided in an embodiment of this application;

[0042] Figure 9 This is a schematic diagram of the connection connector provided in an embodiment of this application;

[0043] Figure 10 This is a schematic diagram of the connecting plate provided in an embodiment of this application;

[0044] Figure 11 This is a schematic diagram of the connection block provided in an embodiment of this application;

[0045] Figure 12 This is a schematic diagram of the loading cylinder provided in an embodiment of this application;

[0046] in:

[0047] 1-Panel structure; 2-Vibration support fixture; 3-Prestressed loading fixture;

[0048] 11-Skin; 12-Firming strip;

[0049] 21-Base plate; 22-Support base;

[0050] 31-Slide; 32-Force sensor; 33-Connecting joint; 34-Connecting plate; 35-Connecting block; 36-Screw; 37-Loading cylinder.

[0051] To better illustrate this embodiment, some content in the accompanying drawings may be omitted, enlarged, or reduced. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0052] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0053] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The word "comprising" as used in this application description indicates that the concept preceding the word encompasses the concepts listed following the word and their equivalents, without excluding other related concepts.

[0054] Furthermore, the terms indicating location used in the description of this application are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation" and "connection" used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0055] Aircraft upper panel structure 1 typically includes a skin 11 and multiple ribs 12 arranged on the skin 11. During vibration fatigue testing, a portion of the skin 11 containing two ribs 12 can be cut for testing. Figure 1 As shown, the part of the wall panel structure 1 where in-plane prestressing is applied is the edge of the skin 11 parallel to the two reinforcing bars 12.

[0056] A vibration fatigue testing system for in-plane prestressed loading of aircraft panel structures includes a vibration support fixture 2 and a prestressed loading fixture 3, such as... Figure 2 As shown.

[0057] Vibration support fixture 2 and prestress loading fixture 3 are connected to the wall panel structure 1. The prestress loading fixture 3 is used to apply in-plane prestress to the wall panel structure 1, including tensile prestress and compressive prestress. The vibration support fixture 2 is used to support the wall panel structure 1, the prestress loading fixture 3, and to connect to the vibration table to perform vibration loading on the wall panel structure 1.

[0058] Vibration support fixture 2 includes a base plate 21 and a support base 22, such as Figure 3 As shown.

[0059] The base plate 21 can be designed to be rectangular, such as... Figure 4 As shown, it is used to connect to the vibration table, specifically by means of screws.

[0060] There are two support seats 22, which are slidably connected to the base plate 21. Specifically, the support seats 22 can be designed to be connected to the base plate 21 by screws. The corresponding screw holes on the support seats 22 are strip holes. When the screws are loosened, the support seats 22 can slide along the strip holes. After the screws are tightened, the support seats 22 are fixed to the base plate 21.

[0061] Two support bases 22 are arranged axially along the base plate 21, and strip holes on them extend axially along the base plate 21.

[0062] Two support bases 22 are used to connect to the two stiffeners 12 of the wall panel structure 1, specifically by screws.

[0063] The two support seats 22 can be further designed with strip-shaped connecting protrusions, which are stepped and connected to the rib 12 by screws at the top.

[0064] When in-plane prestress is applied to the wall panel structure 1, the wall panel structure 1 will deform. The support seat 22 connected to the upper stiffener 12 of the wall panel structure 1 is designed to slide relative to the base plate 21, which can eliminate the installation error of the wall panel structure 1.

[0065] The shape of the support base 22 and its distribution on the base plate 21 can be designed according to the shape of the stiffeners 12 on the wall panel structure 1 and their distribution on the base plate 21.

[0066] The prestressed loading fixture 3 includes a slide 31, a force sensor 32, a connecting joint 33, a connecting plate 34, a connecting block 35, a screw 36, and a loading cylinder 37.

[0067] There are two slide blocks 31, which are arranged opposite to each other and slidably connected to the base plate 21. Specifically, the slide blocks 31 can be designed to slide in the dovetail groove opened on the base plate 21 through a dovetail protrusion, and can also be connected to the base plate 21 by screws. The corresponding screw holes on the slide blocks 31 are strip holes. When the screws are loosened, the slide blocks 31 can slide along the strip holes and the dovetail grooves. When the screws are tightened, the slide blocks 31 are fixed to the base plate 21. The strip holes and the dovetail grooves extend axially along the base plate 21. The size of the dovetail protrusion is slightly smaller than the size of the dovetail groove to ensure the sliding of the slide blocks 31, while restricting the displacement of the slide blocks 31 in other directions.

[0068] The slide 31 is used to balance the reaction force caused by the in-plane prestressing loading of the wall panel structure 1, and to adjust the installation error caused by the in-plane prestressing loading. The slide 31 can be further designed as an L-shaped plate, such as... Figure 7 As shown, the dovetail protrusion is located at the bottom of the horizontal plate, and angular support ribs are provided between the horizontal plate and the vertical plate.

[0069] Force sensor 32 has two, such as Figure 8 As shown, it is cylindrical and connected to the slide 31. Specifically, it can be connected to the vertical plate of the slide 31 by screws. It is used to measure the magnitude of the prestress loading on the wall panel structure 1.

[0070] There are two connectors 33, such as Figure 9 As shown, the threads are connected to the two force sensors 32.

[0071] There are two connecting plates 34, such as Figure 10As shown, one side edge is hinged to two connecting joints 33. Specifically, it can be hinged to the double-ear structure set on the connecting joint 33 by a pin. The edge of the connecting plate 34 is designed to be arc-shaped, and the pin is located in the middle of the edge, at the maximum arc.

[0072] The other edge of the connecting plate 34 is used to connect to the edges of the skin 11 on both sides of the wall panel structure 1. Specifically, it can be connected to the edge of the skin 11 by a pin. The shape of this edge of the connecting plate 34 is designed according to the shape of the edge connected to the skin 11. In order to make the in-plane prestress loading of the wall panel structure 1 uniformly distributed, a notch can be opened on this edge.

[0073] There are two connecting blocks 35, such as Figure 11 As shown, it is connected to the slide 31, specifically by screws to the vertical plate of the slide 31, and is located above the force sensor 32.

[0074] There are two screws 36 with opposite thread directions, and one end is threaded to two connecting blocks 35.

[0075] The loading cylinder 37 is threaded to the other end of the two screws 36 at both ends. Thus, by rotating the loading cylinder 37, the two slide blocks 31 can be driven to slide on the base plate 21, thereby realizing the loading of prestress in the wall panel structure 1. In order to facilitate the rotation of the loading cylinder 37, the outer wall of the loading cylinder 37 is designed to be regular hexagonal, and nuts are set on the two screws 36. After the prestress in the wall panel structure 1 is loaded in place, the nuts are tightened and pressed against the two ends of the loading cylinder 37 for positioning.

[0076] The above embodiments disclose the design and application of an in-plane prestressed vibration fatigue testing system for aircraft panel structures, which can be carried out by referring to the following steps:

[0077] Step 1: Based on the shape of the wall panel structure 1, determine the holes on the wall panel structure 1, as well as the shape, size and holes of the two support seats 22, and the shape, size and holes of the connecting plate 34.

[0078] Step 2: Based on the magnitude of the in-plane prestress loading, determine the size and depth of the internal threads at both ends of the loading cylinder 37, as well as the size of the external threads of the two screws 36, the initial depth of their entry into the loading cylinder 37, and the selection of the force sensor 32. The depth of the internal threads of the loading cylinder 37 should be greater than the initial entry length of the screws 36, and the depth should be sufficient to ensure that the thread depth is usable when applying in-plane tensile stress. At the same time, it should also be ensured that the initial entry depth of the screws 36 into the loading cylinder 37 is appropriate so that the thread unscrewing depth is sufficient when applying in-plane compressive stress. In addition, determine the corresponding hole positions on the bottom support plate 21 according to the connection hole positions of the vibration table.

[0079] Step 3: By estimating the deformation of the wall panel structure 1, design the dimensions of the strip hole on the support 22, the dimensions of the strip hole on the slide 31, and the length of the dovetail groove to ensure that the system has sufficient tolerance for installation when in-plane prestress is applied.

[0080] Step 4: Coordinate the dimensions of other structures to ensure effective connection and force transmission.

[0081] Step 6: Complete the connection between the bottom support plate 21 and the vibration table.

[0082] Step 7: Complete the connection between the wall panel structure 1 and the two support bases 22, and place it on the bottom support plate 21. Make sure that the center of the connecting strip hole on the support base 22 is aligned with the center line of the corresponding threaded hole on the bottom support plate 21.

[0083] Step 8: Complete the connection between the wall panel structure 1 and the connecting plate 34.

[0084] Step 9: Complete the connection of slide 31, force sensor 32 and connecting joint 33 in sequence.

[0085] Step 10: Slide the dovetail boss into the dovetail groove and connect the connector 33 and the connecting plate 34 with the pin.

[0086] Step 11: Install two nuts on the two screws 36 to complete the connection between the connecting plate 34, the screws 36 and the loading cylinder 37, ensuring that the two screws 36 enter the loading cylinder 37 by equal lengths. Adjust the length by rotating the loading cylinder 37 to ensure that it can be placed between the two slides 31, and connect the connecting block 35 and the slide 31 with screws.

[0087] Step 12: Adjust the tensile and compressive prestresses on the wall panel structure by rotating the loading cylinder 37 to the left and right. Determine whether the loading is in place by measuring the force value of the force sensor 32. After loading is in place, tighten the nuts on the two screws 36.

[0088] Step 13: Tighten the screws connecting the base plate 21 to the support 22, and tighten the screws connecting the base plate 21 to the slide 31.

[0089] The above embodiments disclose an in-plane prestressed vibration fatigue testing system for aircraft panel structures:

[0090] By having the strip holes on the two support seats 22 engage with the threaded holes on the base plate 21, the influence of the deformation of the wall panel structure 1 caused by in-plane prestress loading on the installation of the support seats 22 can be eliminated, while ensuring the application of in-plane prestress.

[0091] The slide block 31 is provided with a dovetail-shaped boss, which cooperates with the dovetail-shaped groove on the base plate 21. This allows for free movement in the direction of in-plane prestress application, ensuring the application of in-plane prestress to the wall panel structure 1. It also restricts displacement and deformation in other directions, ensuring that the direction of in-plane prestress remains unchanged during the application of in-plane prestress.

[0092] The system is reliable and the method for applying in-plane prestress to the wall panel structure is simple. By rotating the loading cylinder 37 left and right, the tensile and compressive prestresses in-plane of the wall panel structure can be accurately applied. At the same time, with the nuts on the two screws 36, the in-plane prestress of the wall panel structure can be kept constant during vibration. In addition, the magnitude of the in-plane prestress of the wall panel structure can be obtained in real time through the force sensor 32.

[0093] After the prestress is applied to the wall panel structure 1, the screws connecting the base plate 21 to the support 22 and the screws connecting the base plate 21 to the slide 31 are tightened to ensure that the prestress on the wall panel structure 1 remains unchanged as the internal force of the system, and does not affect the vibration system.

[0094] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A prestressed vibration fatigue testing system for an aircraft panel structure, characterized in that, Including vibration support fixture (2) and prestressed loading fixture (3); The vibration support fixture (2) includes a base plate (21) and a support base (22); The base plate (21) is used to connect to the vibration table; There are two support seats (22), which are slidably connected to the base plate (21). The two support seats (22) are used to connect to the two ribs (12) of the wall panel structure (1), which are located below the skin (11) of the wall panel structure (1). The prestressed loading fixture (3) includes a slide (31), a force sensor (32), a connecting joint (33), a connecting plate (34), a connecting block (35), a screw (36), and a loading cylinder (37); There are two slide blocks (31), which are arranged opposite to each other and are slidably connected to the base plate (21); There are two force sensors (32), which are connected to the slide (31); There are two connectors (33), which are connected to two force sensors (32); There are two connecting plates (34), one edge of which is hinged to two connecting joints (33), and the other edge is used to connect to the edges of the skin (11) of the wall panel structure (1); There are two connecting blocks (35), which are connected to the slide (31); There are two screws (36) with opposite threads, and one end is threaded to two connecting blocks (35); The loading cylinder (37) is threaded at both ends to the other end of the two screws (36).

2. The in-plane prestressed vibration fatigue test system for aircraft panel structures according to claim 1, characterized in that, The base plate (21) is rectangular and is connected to the vibration table by screws; Two support bases (22) are connected to the base plate (21) by screws, and the corresponding screw holes on the support bases (22) are strip holes; Two support bases (22) are arranged axially along the base plate (21), and the strip holes on them extend axially along the base plate (21); The two support bases (22) have strip-shaped connecting protrusions, which are stepped and connected to the rib (12) by screws at the top.

3. The in-plane prestressed vibration fatigue testing system for aircraft panel structures according to claim 2, characterized in that, The slide (31) is slidably connected to the dovetail groove on the base plate (21) by a dovetail protrusion; The slide (31) is connected to the base plate (21) by screws, and the corresponding screw holes on the slide (31) are strip holes.

4. The in-plane prestressed vibration fatigue testing system for aircraft panel structures according to claim 3, characterized in that, The slide (31) is an L-shaped plate, with angular support ribs provided between its horizontal plate and vertical plate; The swallowtail-shaped protrusion is located at the bottom of the horizontal plate.

5. The in-plane prestressed vibration fatigue testing system for aircraft panel structures according to claim 4, characterized in that, Two force sensors (32) are connected to the vertical plate of the slide (31) by screws.

6. The in-plane prestressed vibration fatigue testing system for aircraft panel structures according to claim 5, characterized in that, Two connecting blocks (35) are connected to the vertical plate of the slide (31) by screws and are located above the force sensor (32).

7. The in-plane prestressed vibration fatigue testing system for aircraft panel structures according to claim 6, characterized in that, Two connectors (33) are threaded onto two force sensors (32).

8. The in-plane prestressed vibration fatigue testing system for aircraft panel structures according to claim 7, characterized in that, Two connecting plates (34) are hinged to the double-ear structure set on the connecting joint (33) by pins, and the edge of the connecting plate (34) and the connecting joint (33) is arc-shaped.

9. The in-plane prestressed vibration fatigue testing system for aircraft panel structures according to claim 8, characterized in that, The connecting plate (34) is attached to the edge of the skin (11) by means of pins.

10. The in-plane prestressed vibration fatigue testing system for aircraft panel structures according to claim 9, characterized in that, The outer wall of the loading cylinder (37) is a regular hexagon.

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