Supporting wing layout gust reduction or flutter suppression hinge wingtip structure and method

Abstract

The invention discloses a hinge wingtip structure and method for supporting wing layout gust reduction or flutter suppression, and belongs to the field of wind tunnel tests. The aircraft comprises a nose, a wing connecting piece, a middle aircraft body, a rear aircraft body, a vertical fin, a horizontal tail, a nacelle hanging frame, a main wing, a hinge structure, a wingtip, a nacelle, an auxiliary supporting wing and a supporting wing, the nose and the rear aircraft body are installed on the front side and the rear side of the middle aircraft body respectively, the vertical fin is arranged on the rear side of the rear aircraft body, the horizontal tail is installed on the vertical fin, and the main wing is installed on the middle aircraft body through the wing connecting piece; the wingtips are installed at the ends of the main wings through hinge structures, the two ends of the supporting wings are connected with the middle fuselage and the main wings respectively, the two ends of the auxiliary supporting wings are connected with the main wings and the supporting wings respectively, and the nacelles are installed on the supporting wings through nacelle hangers. The problems that according to traditional gust load slowing, a steering engine is used for controlling wing surface deflection, time delay is caused, and the control effect is poor are solved, the angle of the wingtip can be changed in time along with gust disturbance, then the wing root bending moment is reduced, and the purpose of gust load slowing or flutter suppression is achieved.

Description

Technical Field

[0001] This invention relates to a hinged wingtip structure and method for supporting wing layout to reduce gusts or suppress flutter, belonging to the field of wind tunnel testing. Background Technology

[0002] The atmospheric environment in which aircraft fly is not always stable and is often subject to disturbances. "Gusts" are a typical manifestation of this phenomenon, referring to sudden changes in wind speed and direction in a short period of time, often caused by weather conditions or terrain effects.

[0003] As a novel configuration, the straddle-wing aircraft features a higher aspect ratio and a smaller sweep angle, which helps improve the lift-to-drag ratio and reduce induced drag, thereby reducing thrust requirements and fuel consumption, showing promising application prospects in next-generation civil aircraft design. However, this configuration also brings problems such as relatively more flexible wing stiffness and lower wing loading, making it more susceptible to gust disturbances and exhibiting more pronounced flutter issues. Therefore, the need for gust load mitigation and flutter suppression technologies is increasingly urgent. Simultaneously, with the increasing demands for passenger comfort and safety in the civil aircraft industry, reducing gust response and improving flutter speed have become important constraints in straddle-wing aircraft design.

[0004] To ensure flight safety and passenger comfort, research on gust and flutter characteristics is essential, and wind tunnel testing is an effective way to implement related mitigation and suppression technologies. Currently, there is considerable experience in gust load mitigation and flutter suppression methods based on control surface deflection. This method primarily involves placing acceleration sensors and strain gauges on the wing to collect wingtip overload and wing root bending moment signals, which are then calculated to drive control surface deflection to counteract gust loads. However, this method has significant drawbacks: there is a time delay throughout the entire process from signal acquisition and calculation to control mechanism action; due to the limited size of the wind tunnel test section, the aerodynamic forces acting on the model have already changed when the control surfaces actually deflect, severely affecting control performance; simultaneously, the installation of control mechanisms and cables increases the model's added mass, affecting measurement accuracy, increasing the difficulty of model design and manufacturing, extending the development cycle, and increasing costs.

[0005] Therefore, there is an urgent need to propose a hinged wingtip structure and method for supporting wing layout to mitigate gusts or suppress flutter, in order to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a hinged wingtip structure and method for mitigating gusts or suppressing flutter in support wing configurations, aiming to overcome the inherent defects of motor-driven control surfaces in traditional technologies. By simplifying the deflection process, it effectively overcomes the problems of low control efficiency and poor performance of traditional solutions. Furthermore, by eliminating the need for motors and cables, it eliminates the interference of added mass on measurements, significantly reducing the design difficulty, manufacturing cost, and cycle time of the model. A brief overview of the invention is provided below to offer a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0007] The technical solution of this invention:

[0008] Option 1: A hinged wingtip structure for gust mitigation or flutter suppression with a supported wing configuration, comprising a nose, wing connectors, a mid-fuselage, connecting plates, a rear fuselage, a vertical tail, a horizontal tail, a nacelle pylon, a main wing, a hinged structure, wingtips, a nacelle, an auxiliary support wing, and a support wing. The nose and rear fuselage are respectively mounted on the front and rear sides of the mid-fuselage. A vertical tail is located on the rear side of the rear fuselage, and a horizontal tail is mounted on the vertical tail. The main wing is mounted to the mid-fuselage via wing connectors, and the wingtip is mounted to the tip of the main wing via a hinged structure. The two ends of the support wing are connected to the mid-fuselage and the main wing, respectively. The two ends of the auxiliary support wing are connected to the main wing and the support wing, respectively. The nacelle is mounted to the support wing via a nacelle pylon. The nose, mid-fuselage, and rear fuselage are all fixed to the wind tunnel sidewall via connecting plates.

[0009] Preferably, the hinge structure includes a first pin, a first socket, a pivot, a torsion spring, a second socket, a first lug, a second pin, a third socket, a fourth socket, and a second lug. The first and second sockets are both mounted on the main wing via the first lug. The third and fourth sockets are both mounted on the wingtip via the second lug. The third, first, second, and fourth sockets are all rotatably mounted on the pivot. The pivot has a first pin and a second pin at both ends. The torsion spring is fitted onto the pivot and its two ends are connected to the first and second lugs, respectively.

[0010] Preferably, the main wing and the wingtip are locked together by a fixing rod.

[0011] Preferred method: The model structure dynamics design method for the main wing and wingtip is as follows:

[0012] S1.1 Establish a finite element model of the real aircraft mechanism and perform structural dynamics analysis to obtain the model mass characteristics, stiffness characteristics, etc. of the main wing and wingtip.

[0013] S1.2, simplify the actual aircraft mechanism, establish a simplified finite element model, and perform structural dynamics analysis to obtain the model's mass distribution, stiffness characteristics, etc.

[0014] S1.3, compare the structural dynamic characteristics of the real aircraft and the simplified model to see if they are equivalent. If they are not equivalent, then modify the finite element model of the simplified model by adjusting the mass distribution, stiffness distribution, etc., until they are equivalent. Finally, establish an equivalent simplified model.

[0015] S1.4, Scale down the equivalent simplified model;

[0016] S1.5 After determining the scale, the model structure design of the main wing and wingtip is carried out, and the detailed design of the physical model of the main wing and wingtip is obtained. The finite element model of the detailed design model is established and its structural dynamic characteristics are extracted.

[0017] S1.6 compares whether the structural dynamic characteristics of the scaled-down design model and the equivalent simplified model are equivalent. If they are not equivalent, the finite element model is corrected by adjusting the mass distribution and stiffness distribution until they are equivalent.

[0018] Preferred design method for the hinge structure is as follows:

[0019] S2.1 First, perform load calculations on the hinge structure to obtain the lift, drag, and bending moment of the hinge structure;

[0020] S2.2, Select and design the torsion spring structure based on the lift, resistance and bending moment of the hinge structure;

[0021] S2.3, hinge structure assembly, which involves connecting and installing the first pin, first socket, pivot, second socket, first lug, second pin, third socket, fourth socket and second lug with the selected torsion spring.

[0022] Option 2, a wind tunnel test method for mitigating gust loads in a supported wing configuration, is based on the hinged wingtip structure for mitigating gust loads or suppressing flutter described in Option 1. The specific steps are as follows:

[0023] Step 1: Design the first-order bending frequencies of the main wing and wingtip to be within the range of blade oscillation frequencies that occur during gusts;

[0024] Step 2 involves fabricating the wing model and conducting ground modal tests to obtain the model vibration modes, frequencies, and other structural dynamic characteristics of the hinged wingtip structure for gust mitigation or flutter suppression of the supported wing layout, and to provide input for finite element model correction.

[0025] Step 3: Install strain gauges at the root of the main wing to measure the bending moment at the root of the model.

[0026] Step 4: Install accelerometers at the junction of the wingtip and the main wing to measure the gust response and vibration characteristics at this location;

[0027] Step 5: Install the gust generator and simultaneously mount the model on the support device on the side wall of the wind tunnel;

[0028] Step 6: First, lock the main wing and wingtip together with the fixing rod to prevent the wingtip from swinging with the gust of wind and obtain the wing bending moment and acceleration response values.

[0029] Step 7: Then pull out the fixing rod. At this time, the wingtip swings with the gust of wind. Obtain the wing bending moment and acceleration response values ​​under the same test conditions as in Step 6, and compare the wing bending moment and acceleration response values ​​with the wing bending moment and acceleration response values ​​obtained in Step 6.

[0030] Step 8: Replace the torsion spring in the hinge structure and compare the mitigation effect of torsion springs with different stiffness under the same gust disturbance conditions.

[0031] Step 9: Change the blade swing angle and oscillation frequency of the gust generator, compare the mitigation effects of different stiffness torsion springs, and select the stiffness torsion spring with the best mitigation effect.

[0032] The present invention has the following beneficial effects:

[0033] 1. This invention directly responds to gust disturbances and drives wingtip deflection through a passive hinged wingtip structure. This process is entirely achieved through the interaction of aerodynamic forces and torsion springs, eliminating a series of complex steps such as signal acquisition, calculation, and servo drive in traditional fly-by-wire control. This fundamentally eliminates the system delay problem, enabling the wingtip to follow gust changes in real time and quickly, thereby more effectively counteracting gust loads and significantly improving the control efficiency and effectiveness of gust load mitigation and flutter suppression.

[0034] 2. This invention greatly simplifies the internal structure of the wind tunnel test model by eliminating the motor, servo motor, and their associated control cables. This not only reduces the design difficulty and processing complexity of the model itself, shortens the processing cycle and manufacturing cost, but more importantly, it avoids the additional mass introduced by installing drive components, effectively improving the accuracy and reliability of test measurements;

[0035] 3. The hinge structure provided by this invention has both "locked" and "free rotation" states. A fixed rod can rigidly connect the wingtip to the main wing, serving as a baseline for testing; removing the fixed rod allows for the study of the mitigation effect under free wingtip deflection. Furthermore, by replacing torsion springs with different stiffnesses, the optimal control parameters for different wind speeds and gust frequencies can be easily studied and selected, providing an efficient and flexible experimental method for optimizing the wingtip layout. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a hinged wingtip structure for gust mitigation or flutter suppression in a support wing layout according to the present invention;

[0037] Figure 2 This is a schematic diagram of the hinge structure of the present invention;

[0038] Figure 3 This is a flowchart of the model structure dynamics design method for the main wing and wingtip described in this invention;

[0039] Figure 4 This is a flowchart of the design method for the hinge structure described in this invention;

[0040] Figure 5 This is a flowchart of a wind tunnel test method for mitigating gust load according to the present invention;

[0041] Figure 6 This is a frequency domain effect diagram of the load mitigation in the second specific implementation method;

[0042] Figure 7 This is a frequency domain effect diagram of the load mitigation in the second specific implementation method.

[0043] In the diagram: 1-nose, 2-wing connector, 3-mid fuselage, 4-connecting piece, 5-rear fuselage, 6-vertical tail, 7-horizontal tail, 8-nacelle pylon, 9-main wing, 10-hinge structure, 11-wingtip, 12-nacelle, 13-auxiliary support wing, 14-slant brace wing, 15-fixing rod, 16-first pin, 17-first socket, 18-shaft, 19-torsion spring, 20-second socket, 21-first lug, 22-second pin, 23-third socket, 24-fourth socket, 25-second lug. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0045] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections (i.e., non-detachable connections) include, but are not limited to, conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include, but are not limited to, conventional disassembly methods such as threaded connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can always be found to achieve the function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a hinged connection can be chosen for detachable connections.

[0046] Specific implementation method one: Combining Figures 1-4This embodiment describes a hinged wingtip structure for gust mitigation or flutter suppression, comprising a nose 1, wing connector 2, mid-fuselage 3, connecting piece 4, rear fuselage 5, vertical tail 6, horizontal tail 7, nacelle pylon 8, main wing 9, hinge structure 10, wingtip 11, nacelle 12, auxiliary support wing 13, and support wing 14. The nose 1 and rear fuselage 5 are respectively mounted on the front and rear sides of the mid-fuselage 3. The vertical tail 6 is located on the rear side of the rear fuselage 5, and the horizontal tail 7 is mounted on the vertical tail 6. The main wing 9 is mounted to the mid-fuselage 3 via wing connector 2. The wingtip 11 is mounted to the end of the main wing 9 via hinge structure 10. The two ends of the support wing 14 are connected to the mid-fuselage 3 and the main wing 9 respectively. The two ends of the auxiliary support wing 13 are connected to the main wing 9 and the support wing 14 respectively. The nacelle 12 is mounted to the support wing 14 via nacelle pylon 8. The nose 1, mid-fuselage 3, and rear fuselage 5 are all fixed to the wind tunnel sidewall via connecting pieces 4. The main wing 9 is also fixed to the wind tunnel sidewall via wing connector 2. The use of hinge structure 10 for gust load mitigation solves the problems of delayed wing surface deflection and poor control effect caused by traditional gust load mitigation using servo motors. This allows the wingtip 11 to change its angle in time with gust disturbances, thereby reducing the wing root bending moment of the main wing 9 and achieving the purpose of gust load mitigation.

[0047] The hinge structure 10 includes a first pin 16, a first socket 17, a pivot 18, a torsion spring 19, a second socket 20, a first lug 21, a second pin 22, a third socket 23, a fourth socket 24, and a second lug 25. The first socket 17 and the second socket 20 are both mounted on the main wing 9 via the first lug 21. The third socket 23 and the fourth socket 24 are both mounted on the wingtip 11 via the second lug 25. The third socket 23, the first socket 17, the second socket 20, and the fourth socket 24 are all rotatably mounted on the pivot 18. The pivot 18 has a first pin 16 and a second pin 22 at both ends. The torsion spring 19 is fitted onto the pivot 18, and its two ends are connected to the first lug 21 and the second lug 25, respectively.

[0048] The main wing 9 and the wingtip 11 are locked together by a fixing rod 15. That is, fixing holes are provided on both sides of the main wing 9 and the wingtip 11, and the two ends of the fixing rod 15 are respectively inserted into the fixing holes to lock the main wing 9 and the wingtip together.

[0049] The model structure dynamics design method for the main wing 9 and wingtip 11 is as follows:

[0050] S1.1 Establish a finite element model of the real aircraft mechanism and perform structural dynamics analysis to obtain the model mass characteristics, stiffness characteristics, frequency and damping values ​​of the main wing 9 and wingtip 11.

[0051] S1.2, simplify the actual aircraft mechanism, establish a simplified finite element model, and perform structural dynamics analysis to obtain the model's mass distribution, stiffness characteristics, frequency, and damping value.

[0052] S1.3, compare the structural dynamic characteristics of the real aircraft and the simplified model to see if they are equivalent. If they are not equivalent, then modify the finite element model of the simplified model by adjusting the mass distribution and stiffness distribution until they are equivalent. Finally, establish an equivalent simplified model.

[0053] S1.4, the scaled-down design of the equivalent simplified model must meet the following scaling criteria:

[0054] a) Length scale The ratio of the equivalent simplified model geometry to the simulated aircraft structural geometry:

[0055] (1)

[0056] in Indicates the length of the designed structural dynamics model. This is the actual length of the aircraft.

[0057] In addition, for low-speed wind tunnels, the length scale needs to be selected according to the actual situation of the wind tunnel, such as the width of the wind tunnel, and the ratio of the model cross-sectional area to the wind tunnel area must meet the blockage requirements.

[0058] b) Speed ​​Scale The design wind tunnel test flutter velocity V selected during model design m The simulated critical speed V of aircraft flutter s The ratio.

[0059] (2)

[0060] c) Density ratio Wind tunnel operating density Atmospheric density at altitudes corresponding to the simulated critical flutter velocity of an aircraft The ratio.

[0061] (3)

[0062] Based on the above three basic scales, namely the length scale Speed ​​scale and density ratio The following scale relationships can be derived:

[0063] d) Speed-pressure ratio :

[0064] (4)

[0065] e) Quality :

[0066] (5)

[0067] f) Stiffness ratio :

[0068] (6)

[0069] g) Frequency ratio :

[0070] (7)

[0071] h) Skin thickness ratio :

[0072] (8)

[0073] i) Beam rib thickness ratio :

[0074] (9)

[0075] S1.5 After determining the scale, the model structure design of the main wing 9 and wingtip 11 is carried out, and the detailed design of the physical model of the main wing 9 and wingtip 11 is obtained. The finite element model of the detailed design model is established and its structural dynamic characteristics are extracted.

[0076] S1.6 compares whether the structural dynamic characteristics of the scaled-down design model and the equivalent simplified model are equivalent. If they are not equivalent, the finite element model is corrected by adjusting the mass distribution and stiffness distribution until they are equivalent.

[0077] The design method of the hinge structure 10 is as follows:

[0078] S2.1 First, perform load calculations on hinge structure 10 to obtain the lift, drag, and bending moment of hinge structure 10.

[0079] Specifically, the following formula is used for estimation:

[0080] a. Lift L y Estimate:

[0081] (10)

[0082] b. Resistance estimation:

[0083] (11)

[0084] In equations (10) and (11): To test wind speed ( ), Angle of attack (radians). This is the spanwise coordinate of the wing (positive direction points to the wingtip, unit is m).

[0085] c. Moment estimation for hinge structure 10:

[0086] The bending moment at hinge structure 10 can be calculated using integration. In this embodiment, the wing model has a span of 1.5m, and hinge structure 10 is located approximately 91.3m from the main wing. The calculation requires determining the bending moment of the hinge due to the aerodynamic load from hinge structure 10 to the wingtip 11. The calculation formula is as follows:

[0087] (12)

[0088] S2.2, Select and design the torsion spring 19 structure based on the lift, resistance and bending moment of the hinge structure 10;

[0089] In this embodiment, the torsion spring 19 is selected as a cylindrical helical torsion spring, and its function is to restore the wingtip. The external load applied to the cylindrical helical torsion spring is torque. When the torsion spring 19 is subjected to torque in a plane perpendicular to the spring axis, the normal section of the spring wire of the torsion spring 19 is mainly subjected to bending moment, which can be approximated as being subjected to bending moment. The bending stress generated by a bending beam can be expressed as follows:

[0090] (13)

[0091] In the formula: The section modulus of the circular spring wire ( ), ; is the curvature coefficient of the spring wire. C is the twist ratio, and commonly used C values ​​are 4 to 16.

[0092] The deformation of the torsion spring 19 under load is determined by its angular displacement. The torsion spring 19 is subjected to torque. The action produces torsional deformation using the torsion angle This means that an approximate calculation is performed using formulas from mechanics of materials, namely:

[0093] (14)

[0094] In the formula: This refers to the number of working revolutions (effective revolutions). The elastic modulus of the spring wire (MPa); The moment of inertia of the spring wire cross section ( For circular cross-sections .

[0095] The stiffness of torsion spring 19 was determined. for:

[0096] (15)

[0097] In the formula: The outer diameter of the spring is (mm). The diameter of the spring wire is in mm.

[0098] The design steps for torsion spring 19 are as follows:

[0099] a. Select materials and determine their allowable bending stress. (MPa)

[0100] b. Select the winding ratio And calculate the curvature coefficient.

[0101]

[0102] c. Calculate the diameter of the spring wire

[0103] From equation (13) achievable .

[0104] d. Determine the outer diameter of the spring

[0105] e. Determine the number of working coils of the spring

[0106] The number of working turns of the torsion spring can be obtained from equation (14). .

[0107] f. Calculate the torsional stiffness of the torsion spring.

[0108] The torsional stiffness of the spring can be calculated from equation (15).

[0109] S2.3, the hinge structure 10 is assembled, that is, the first pin 16, the first socket 17, the pivot 18, the second socket 20, the first lug 21, the second pin 22, the third socket 23, the fourth socket 24 and the second lug 25 are connected and installed with the selected torsion spring 19.

[0110] Specifically, the first lug 21 and the main wing 9 are connected by one M4 slotted countersunk wood screw and two M2.5 slotted countersunk wood screws, and the second lug 25 and the wingtip 11 are connected by one M4 slotted countersunk wood screw and two M2.5 slotted countersunk wood screws. The first lug 21 and the second lug 25 are connected by a pivot 18. The position of the pivot 18 is fixed by two cotter pins that engage with the first pin 16 and the second pin 22 respectively. The torsion spring 19 is placed on the pivot 18, with its two ends inserted into the main wing 9 and the wingtip 11 respectively to achieve its reset function.

[0111] Specific Implementation Method Two: Combining Figures 1-7 This embodiment describes a wind tunnel testing method for mitigating gust loads, based on a wingtip structure with a support wing layout for gust mitigation or flutter suppression as described in Embodiment 1. The specific steps are as follows:

[0112] Step 1: The first-order bending moment frequency of the model responds significantly to gust disturbances. Using structural dynamics model design methods, the first-order bending frequencies of the main wing 9 and wingtip 11 are designed to fall within the range of blade oscillation frequencies during gusts. Within 5Hz, so that a gust field with a larger model response can be generated;

[0113] Step 2: Process the wing model and conduct ground modal tests to obtain the model mode shape, frequency and damping value of the hinged wingtip structure for gust mitigation or flutter suppression of the supported wing layout, and provide input for finite element model correction;

[0114] Step 3: Install strain gauges at the root of the main wing 9 to measure the bending moment at the root of the model.

[0115] Step 4: An accelerometer is installed at the junction of the wingtip 11 and the main wing 9 to measure the gust response and vibration at this location;

[0116] Step 5: Install the gust generator, and at the same time, fix the nose 1, the middle fuselage 3 and the rear fuselage 5 to the support device on the side wall of the wind tunnel through the connecting piece 4.

[0117] Step 6: First, lock the main wing 9 and wingtip 11 together with the fixing rod 15 to prevent the wingtip 11 from swinging with the gust of wind and obtain the wing bending moment and acceleration response values.

[0118] Step 7: Then pull out the fixing rod 15. At this time, the wingtip 11 swings with the gust of wind. Obtain the wing bending moment and acceleration response values ​​under the same test conditions as in Step 6, and compare the wing bending moment and acceleration response values ​​with the wing bending moment and acceleration response values ​​obtained in Step 6.

[0119] Step 8: Replace the torsion spring 19 in the hinge structure 10 and compare the mitigation effect of torsion springs 19 with different stiffnesses under the same gust disturbance conditions.

[0120] Step 9: Change the blade angle and oscillation frequency of the gust generator to mitigate the effect through time-domain manipulation. Figure 6 Time-domain data analysis of strain gauges at the wing root allows for a comparison of mitigation effects when the hinge is extended or retracted at the wingtip. Fourier transform of the time-domain data yields the model's first-order response frequency, which is then used to assess the mitigation effect in the frequency domain. Figure 7 The first-order bending frequency of the model is obtained as the point where the model's response to gust disturbance is at its maximum. Then, the mitigation effects of torsion springs 19 with different stiffnesses are compared, and the torsion spring 19 with the best mitigation effect is selected. Its parameters are used as the design input for the wingtip of the gust load mitigation hinge on the actual aircraft.

[0121] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0122] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hinged wingtip structure for supporting wing layout to mitigate gusts or suppress flutter, characterized in that: The fuselage includes a nose (1), wing connectors (2), mid-fuselage (3), connecting piece (4), rear fuselage (5), vertical tail (6), horizontal tail (7), nacelle pylons (8), main wing (9), hinge structure (10), wingtip (11), nacelle (12), auxiliary support wing (13), and support wing (14). The nose (1) and rear fuselage (5) are respectively installed on the front and rear sides of the mid-fuselage (3). The rear fuselage (5) has a vertical tail (6) on its rear side, and a horizontal tail (7) is installed on the vertical tail (6). The main wing (9) The fuselage is mounted on the mid-fuselage (3) via wing connector (2), the wingtip (11) is mounted on the end of the main wing (9) via hinge structure (10), the two ends of the support wing (14) are connected to the mid-fuselage (3) and the main wing (9) respectively, the two ends of the auxiliary support wing (13) are connected to the main wing (9) and the support wing (14) respectively, the nacelle (12) is mounted on the support wing (14) via nacelle rack (8), and the nose (1), mid-fuselage (3) and rear fuselage (5) are all fixed to the wind tunnel sidewall via connecting piece (4).

2. The hinged wingtip structure for gust mitigation or flutter suppression according to claim 1, characterized in that: The hinge structure (10) includes a first pin (16), a first socket (17), a pivot (18), a torsion spring (19), a second socket (20), a first lug (21), a second pin (22), a third socket (23), a fourth socket (24), and a second lug (25). The first socket (17) and the second socket (20) are both mounted on the main wing (9) via the first lug (21). The third socket (23) and the fourth socket (24) are both mounted on the wingtip (11) via the second lug (25). The third socket (23), the first socket (17), the second socket (20), and the fourth socket (24) are all rotatably mounted on the pivot (18). The pivot (18) has a first pin (16) and a second pin (22) at both ends. The torsion spring (19) is fitted on the pivot (18) and its two ends are connected to the first lug (21) and the second lug (25) respectively.

3. The hinged wingtip structure for gust mitigation or flutter suppression according to claim 2, characterized in that: The main wing (9) and the wingtip (11) are locked together by a fixing rod (15).

4. The hinged wingtip structure for gust mitigation or flutter suppression according to claim 3, characterized in that: The model structure dynamics design method for the main wing (9) and wingtip (11) is as follows: S1.1, Establish a finite element model of the real aircraft mechanism and perform structural dynamics analysis to obtain the model mass characteristics, stiffness characteristics, frequency and damping values ​​of the main wing (9) and wingtip (11); S1.2, simplify the actual aircraft mechanism, establish a simplified finite element model, and perform structural dynamics analysis to obtain the model's mass distribution, stiffness characteristics, frequency and damping value. S1.3, compare the structural dynamic characteristics of the real aircraft and the simplified model to see if they are equivalent. If they are not equivalent, then modify the finite element model of the simplified model by adjusting the mass distribution, stiffness distribution, and frequency until they are equivalent. Finally, establish an equivalent simplified model. S1.4, Scale down the equivalent simplified model; S1.5, after determining the scaled-down dimensions, the model structure design of the main wing (9) and wingtip (11) is carried out, and the detailed design of the physical model of the main wing (9) and wingtip (11) is obtained. The finite element model of the detailed design model is established and its structural dynamic characteristics are extracted. S1.6 compares whether the structural dynamic characteristics of the scaled-down design model and the equivalent simplified model are equivalent. If they are not equivalent, the finite element model is corrected by adjusting the mass distribution and stiffness distribution until they are equivalent.

5. A hinged wingtip structure for gust mitigation or flutter suppression according to claim 4, characterized in that: The design method of the hinge structure (10) is as follows: S2.1 First, the load calculation of the hinge structure (10) is performed to obtain the lift, drag and bending moment of the hinge structure (10); S2.2, Select and design the torsion spring (19) structure based on the lift, resistance and bending moment of the hinge structure (10); S2.3, the hinge structure (10) is assembled, that is, the first pin (16), the first socket (17), the pivot (18), the second socket (20), the first lug (21), the second pin (22), the third socket (23), the fourth socket (24), and the second lug (25) are connected and installed with the selected torsion spring (19).

6. A wind tunnel test method for mitigating gust loads, based on the gust mitigation or flutter suppression hinged wingtip structure with a supported wing layout as described in claim 5, characterized in that... The specific steps are as follows: Step 1: The first-order bending moment frequency of the model responds significantly to gust disturbances. Using the structural dynamics model design method, the first-order bending frequencies of the main wing (9) and wingtip (11) are designed within the range of blade oscillation frequencies during gusts. Within 5Hz, in order to generate a gust field that allows for a larger model response; Step 2: Process the wing model and conduct ground modal tests to obtain the model mode shape, frequency and damping value of the hinged wingtip structure for gust mitigation or flutter suppression of the supported wing layout, and provide input for finite element model correction; Step 3: Strain gauges are placed at the root of the main wing (9) to measure the bending moment at the root of the model. Step 4: An accelerometer is placed at the junction of the wingtip (11) and the main wing (9) to measure the gust response at this location; Step 5: Install the gust generator, and at the same time fix the nose (1), middle fuselage (3) and rear fuselage (5) to the support device on the side wall of the wind tunnel through the connecting piece (4). Step 6: First, lock the main wing (9) and wingtip (11) together with the fixing rod (15) so that the wingtip (11) cannot swing with the gust of wind and obtain the wing bending moment and acceleration response values. Step 7, then pull out the fixing rod (15). At this time, the wingtip (11) swings with the gust of wind. Obtain the wing bending moment and acceleration response values ​​under the same test conditions as in step 6, and compare the wing bending moment and acceleration response values ​​with the wing bending moment and acceleration response values ​​obtained in step 6. Step 8: Replace the torsion spring (19) in the hinge structure (10) and compare the mitigation effect of torsion springs (19) with different stiffnesses under the same gust disturbance conditions. Step 9: Change the blade angle and oscillation frequency of the gust generator. By analyzing the time-domain mitigation effect diagram and the strain gauge time-domain data at the wing root, the mitigation effect of the model at the hinge tip with and without the hinge is obtained. The first-order response frequency of the model can be obtained by performing a Fourier transform on the time-domain data. The first-order bending frequency of the model is obtained by the frequency-domain mitigation effect diagram, which is the maximum point of the model's response to gust disturbance. Then, the mitigation effect of torsion springs (19) with different stiffnesses is compared, and the torsion spring (19) with the best mitigation effect is selected. Its parameters are used as the design input for the hinge tip of the actual aircraft to mitigate gust load.

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