Lightweight wing static strength equivalent loading test method

Abstract

The present application belongs to the technical field of flexible body aircraft, and particularly relates to a lightweight wing static strength equivalent loading test method. The test method comprises the following steps: aerodynamic load calculation; load partitioning and equivalent calculation; test bench installation and clamping; counterweight equivalent loading; static strength and bending-torsional stiffness measurement; and test result recording. By designing the loading counterweight mass and distribution form of the corresponding area, the weight, center of mass position, resultant moment after loading the counterweight, and the aerodynamic load concentrated force, load pressure center, and resultant moment are consistent, thereby solving the problem that the traditional test method cannot accurately simulate the real aerodynamic load distribution. The above test method solves the static strength and stiffness test problem of the bracing rod and rope reinforced flexible wing structure by using a flexible wing static strength test bench, realizes the static strength and stiffness test function of the flexible wing under variable stiffness by changing the height of the support beam, and realizes high-precision equivalence of the loading counterweight and the design load by using a flexible loading counterweight module.

Description

Technical Field

[0001] This invention belongs to the field of flexible body aircraft technology, specifically relating to a method for static strength equivalent loading test of lightweight wings. Background Technology

[0002] Flexible lightweight wings are primarily used in aircraft structures with strict space requirements. Compared to traditional rigid wings, flexible wings offer significant advantages in terms of cost and weight. However, flexible lightweight wing aircraft are generally weaker than traditional rigid wings, necessitating scientific measurements to meet design requirements.

[0003] Current methods for measuring the static strength of flexible lightweight wings mainly involve laying sandbags flat and suspending heavy objects at the ends. Although this can test the strength and stiffness boundaries, the loading method is relatively crude and differs significantly from the aerodynamic load distribution under actual flight conditions. Therefore, the measurement results cannot fully demonstrate that flexible lightweight wings possess sufficient bending and torsional stiffness under typical operating conditions.

[0004] Considering the significant dispersion in the performance of flexible lightweight wing structures, it is necessary to design a scientific and reasonable equivalent loading method for measuring static strength or stiffness, to solve the prominent problems of traditional measurement methods, and to provide technical support for the structural design optimization of flexible lightweight wings. Summary of the Invention

[0005] In view of this, the present invention provides a method for equivalent loading test of static strength of lightweight wings.

[0006] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0007] In a first aspect, the present invention provides a method for equivalent loading test of static strength of a lightweight wing. This method is based on a static strength test bench for flexible wing testing. The test bench includes a base, a static strength test bench, a pull rope, a displacement gauge, and a flexible loading counterweight module. The bottom of the base is fixedly installed on the ground to support the static strength test bench. The static strength test bench is fixedly installed on the top of the base. A wing clamping mold for holding and fixing the flexible wing test piece is provided at the bottom of the static strength test bench. The pull rope connects the static strength test bench and the wing surface of the flexible wing test piece, and the stiffness of the flexible wing test piece is controlled by the preload of the pull rope. The flexible loading counterweight module is used to apply counterweight to the flexible wing test piece to achieve static strength testing. The displacement gauge is arranged on the ground below the flexible wing test piece to measure the displacement of different positions of the flexible wing test piece before and after loading. The test method includes the following steps: Step 1: Calculate the aerodynamic load; Step 2: Load partitioning and equivalent calculation; Step 3: Installation and clamping of the test stand; Step 4: Equivalent loading of counterweight; Step 5: Static strength and bending / torsional stiffness measurement; Step six: Record the test results.

[0008] Furthermore, step one specifically includes: calculating the aerodynamic load distribution of the flexible wing using computational fluid dynamics methods based on the typical operating conditions of the flexible wing aircraft, extracting the aerodynamic load data, and outputting the data chain of the distribution along the wing surface for each operating condition.

[0009] Furthermore, step two specifically includes: The aerodynamic distributed load under typical working conditions is divided into load zones. The flexible airfoil test piece is divided into multiple regions, the aerodynamic load data is sorted out, the aerodynamic load of each zone is calculated based on the divided regions and converted into equivalent concentrated loads, and the aerodynamic pressure center position of each region is calculated.

[0010] Furthermore, step three specifically includes: preparing a wing clamping mold according to the wing surface shape of the flexible wing test piece; clamping the flexible wing test piece with the wing clamping mold and fixing the wing clamping mold on the top operating plane of the base; tying one end of the pull rope to the top of the static strength test platform and the other end to the wing surface of the flexible wing test piece; inputting high-pressure gas into the flexible wing test piece; completing the inflation and pressure holding process when the gas pressure inside the flexible wing test piece reaches the predetermined test value; adjusting the position of the flexible wing test piece and the length of the pull rope to complete the final test state adjustment of the flexible wing test piece.

[0011] Furthermore, step four specifically includes: based on the partitioning of the flexible wing test piece in step two, designing the loading counterweight mass and distribution pattern for the corresponding regions, so that the loaded weight is consistent with the concentrated force of the aerodynamic load, the position of the center of mass after loading is consistent with the center of pressure of the aerodynamic load, and the resultant moment after loading is consistent with the resultant moment of the aerodynamic load; the flexible loading counterweight module is composed of several loading lead block units connected in series by lead block connecting chains; the flexible loading counterweight module is distributed along the spanwise direction of the flexible wing test piece; the loading lead block units are arranged along the chordal direction of the flexible wing test piece.

[0012] Furthermore, step five specifically includes: setting up multiple displacement gauges on the ground directly below the flexible wing test piece, measuring the displacement of the flexible wing test piece at different positions after loading using multiple displacement gauges, and preliminarily calculating the equivalent stiffness of the flexible wing test piece using the stiffness conversion formula; when the flexible loading counterweight module is uniformly loaded along the chord direction of the flexible wing test piece, and the load centers of each region are kept collinearly distributed along the spanwise direction of the flexible wing test piece, the static strength and stiffness limit tests of the flexible wing test piece under bending conditions can be achieved; when the flexible loading counterweight module is linearly loaded at both ends of the chord direction of the flexible wing test piece, the static strength and stiffness limit tests of the flexible wing test piece under torsional conditions can be achieved.

[0013] Furthermore, step six specifically includes: recording the weight of the flexible loading counterweight module, the center of mass, and the displacement of the flexible wing test piece at the monitoring position under each test condition, and completing the final calculation of static strength and stiffness through conversion formulas.

[0014] Secondly, the present invention provides a flexible wing static strength test bench for the above-mentioned lightweight wing static strength equivalent loading test method, the flexible wing static strength test bench including a base, a static strength test bench, a pull rope, a displacement meter and a flexible loading counterweight module. The bottom of the base is fixedly installed on the ground to support the static strength test bench; The static strength test bench is fixedly installed on the top of the base; the bottom of the static strength test bench is provided with a wing clamping mold for clamping and fixing the flexible wing test piece. The pull rope is connected between the static strength test bench and the wing surface of the flexible wing test piece, and is used to control the stiffness of the flexible wing test piece through pre-tension force. The flexible loading counterweight module is used to load counterweights onto the flexible wing test piece in order to achieve static strength testing of the flexible wing test piece; The displacement gauge is placed on the ground below the flexible wing test piece and is used to measure the displacement of the flexible wing test piece at different positions before and after loading.

[0015] Furthermore, the base includes a main base for the test bench, a side stabilization frame, and a ground stabilization frame; The main base of the test bench is located directly below the wing clamping mold. It is a box-beam structure made of high-strength steel and is fixed to the ground of the test area by bolts. The side stabilization frame is welded to both sides of the main base of the test bench to enhance the lateral (chordal) stability of the main base of the test bench; both the side stabilization frame and the ground stabilization frame are triangular truss structures; the ground stabilization frame is welded to both sides of the side stabilization frame and fixed to the ground to enhance the longitudinal (spanwise) stability of the main base of the test bench. The flexible loading counterweight module is composed of several loading lead block units connected in series by lead block connecting chains; the flexible loading counterweight module is distributed along the spanwise direction of the flexible wing test piece; the loading lead block units are arranged along the chordwise direction of the flexible wing test piece.

[0016] Furthermore, the static strength testing platform also includes a supporting main beam, a supporting crossbeam, a rope tethering contact point, and a crossbeam fixing rod; The wing clamping mold is fixed on the operating plane on the top of the main base of the test bench by a clamping device; the wing clamping mold is a square structure made of stainless steel or high-strength aluminum alloy and is provided with airfoil molding holes; the airfoil molding holes are through holes that penetrate the wing clamping mold and are completely fitted with the airfoil section at the wing root after the flexible wing test piece is filled with air, for clamping and fixing the flexible wing test piece; The top surface of the wing clamping mold is provided with regularly arranged through slots; the through slots are connected to the airfoil mold mounting holes and are used to place air nozzles when the flexible wing test piece is clamped in the wing clamping mold, so as to prevent the air nozzles from being excessively squeezed by the wing clamping mold, causing air blockage or damage. Two main support beams are symmetrically arranged on both sides of the wing clamping mold, and the two main support beams are fixedly installed on the operating plane of the main base of the test bench; both the main support beams and the crossbeams are square beam structures made of high-strength manganese alloy steel; the main support beams are provided with multiple relief holes, which are used to pass through the crossbeam fixing rods to fix the crossbeams; the crossbeams span between the two main support beams and are fixed to the two main support beams by the crossbeam fixing rods passing through the relief holes in the two main support beams; the crossbeams are provided with pull rope tethering protrusions for tying one end of the pull rope; the other end of the pull rope is tied to a handle on the wing surface.

[0017] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. The equivalent loading test method for static strength of lightweight wings of the present invention solves the problem that the static strength and stiffness of large loads or heterogeneous flexible wings cannot be effectively tested; it overcomes the difficulty that the existing static strength test of flexible wings only roughly tests by placing sandbags directly on the wing surface, and cannot accurately simulate the equivalent loading according to the typical working conditions of flexible wing aircraft; the equivalent loading test method can also be applied to the strength measurement of ordinary rigid wings, and has good versatility.

[0018] 2. The static strength equivalent loading test method for lightweight wings of the present invention utilizes a flexible wing static strength test bench, filling the gap in equipment and methods for testing the static strength of large aspect ratio heavy-load flexible wings. By using wing clamping molds and airfoil mounting holes, specialized clamps can be designed according to the shape of the flexible wing type. The close-fitting clamping method enhances stability during static strength testing and improves test accuracy.

[0019] 3. The static strength test bench for flexible wings of the present invention can adjust the height of the supporting crossbeam by means of the supporting main beam and the crossbeam fixing rod, thereby overcoming the problem of static strength and stiffness testing of flexible wing structures reinforced by struts and ropes. It also realizes the static strength and stiffness testing function of flexible wing structures under variable stiffness by changing the height of the supporting crossbeam. Compared with the traditional rough sandbag loading, the present invention achieves high-precision equivalence between the loaded counterweight and the design load through the flexible loading counterweight module. It can also test the static strength, stiffness limit and instability boundary of the flexible wing under heavy load conditions by stacking the flexible loading counterweight modules while loading the counterweight.

[0020] 4. The lightweight wing static strength equivalent loading test method of the present invention divides the wing into sections and designs the loading counterweight mass and distribution pattern of the corresponding areas to ensure that the weight, center of mass position, resultant moment after loading are consistent with the aerodynamic load concentrated force, load center of pressure, and resultant moment, thus solving the problem that traditional test methods cannot accurately simulate the distribution of real aerodynamic loads.

[0021] Based on the above reasons, the lightweight wing static strength equivalent loading test method and flexible wing static strength test stand of the present invention can be widely used in the field of flexible body aircraft technology. Attached Figure Description

[0022] Figure 1 This is a flowchart of the equivalent loading test method for the static strength of a lightweight wing according to the present invention; Figure 2 This is a general layout diagram of the flexible wing static strength test bench used in the equivalent loading test method for the static strength of lightweight wings of the present invention. Figure 3 A three-dimensional schematic diagram of the static strength testing platform and its base; Figure 4 This is a schematic diagram of a flexible loading counterweight module; Figure 5A and Figure 5B This is a schematic diagram of the equivalent loading partition of the flexible wing test specimen; Figure 6 This is a schematic diagram of a single-layer loading of a flexible loading counterweight module; Figure 7 This is a schematic diagram of multi-layer loading for a flexible loading counterweight module.

[0023] Figure label: 1-Static strength test bench; 2-Base; 3-Flexible wing test piece; 101-Pull rope; 201-Displacement gauge; 301-Flexible loading counterweight module; 10-Wing bearing mold; 11-Airfoil mold mounting hole; 12-Main support beam; 13-Support crossbeam; 14-Pull rope tethering contact protrusion; 15-Crossbeam fixing rod; 20-Main base of test bench; 21-Side stabilization frame; 22-Ground stabilization frame; 501-Loading lead block unit; 502-Lead block connecting chain. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0026] Example 1 like Figure 2 and Figure 3 As shown, this embodiment provides a flexible wing static strength test bench, which is used to implement the equivalent loading test method for the static strength of lightweight wings, and includes a base 2, a static strength test bench 1, a tension rope 101, a displacement gauge 201, and a flexible loading counterweight module 301; wherein: The base 2 is fixedly installed on the ground to support the static strength testing platform 1. The static strength testing platform 1 is fixedly installed on the top of the base 2; the static strength testing platform 1 is the main platform for clamping and testing the flexible wing test piece 3, and its bottom is equipped with a wing clamping mold for clamping and fixing the flexible wing test piece 3. A pull rope 101 is connected between the static strength testing platform 1 and the wing surface of the flexible wing test piece 3 to control the stiffness of the flexible wing test piece 3 through preload. A flexible loading counterweight module 301 is used to load counterweights onto the flexible wing test piece 3 to achieve the static strength test of the flexible wing test piece 3. A displacement gauge 201 is arranged on the ground below the flexible wing test piece 3 to measure the displacement of the flexible wing test piece 3 at different positions before and after loading.

[0027] like Figure 2As shown, the base 2 includes a test bench main base 20, a side stabilization frame 21, and a ground stabilization frame 22. The test bench main base 20 is located directly below the wing clamping mold and is a box-beam structure made of high-strength steel, fixed to the ground of the test area by bolts. The side stabilization frame 21 is welded to both sides of the test bench main base 20 to enhance the lateral stability of the test bench main base 20 (the lateral stability of the test bench main base 20 is the chord direction of the flexible wing test piece 3). Both the side stabilization frame 21 and the ground stabilization frame 22 are triangular truss structures. The ground stabilization frame 22 is welded to both sides of the side stabilization frame 21 and fixed to the ground to enhance the longitudinal stability of the test bench main base 20 (the longitudinal stability of the test bench main base 20 is the spanwise stability of the flexible wing test piece 3).

[0028] like Figure 4 , Figure 6 and Figure 7 As shown, the flexible loading counterweight module 301 is used as a loading counterweight during the static strength test of the flexible wing test piece 3. It is composed of several loading lead block units 501 connected in series by lead block connecting chains 502. The lead block connecting chains 502 connect several square or other shaped loading lead block units 501 in series to form a strip-shaped flexible loading counterweight unit. The flexible loading counterweight module 301 is distributed along the spanwise direction of the flexible wing test piece 3. The loading lead block units 501 are arranged along the chordwise direction of the flexible wing test piece 3. The total mass and center of mass of the flexible loading counterweight module 301 arranged on the flexible wing test piece 3 coincide with the calculated aerodynamic equivalent load and equivalent pressure center position, thus completing the equivalent loading of the flexible wing test piece 3. The flexible loading counterweight module 301 is used to complete the equivalent loading in each region of the flexible wing test piece 3. When a single layer of flexible loading counterweight module 301 covering the surface of the flexible wing test piece 3 is insufficient to achieve an equivalent aerodynamic load, static strength testing of the flexible wing test piece 3 under heavy load conditions can be achieved by using stacked flexible loading counterweight modules 301. Since the flexible loading counterweight module 301 uses a flexible lead block connecting chain 502, the strip-shaped flexible loading counterweight unit formed by its series connection can better conform to the wing surface shape when loaded onto the surface of the flexible wing test piece 3. When the size of the loading lead block unit 501 is small, the accuracy of the equivalent loading is better; the fitted flexible loading counterweight module 301 can increase the contact area with the flexible wing test piece 3, making it less prone to slippage.

[0029] like Figure 3As shown, the static strength testing platform 1 also includes two supporting main beams 12, a supporting crossbeam 13, a rope tethering contact 14, and a crossbeam fixing rod 15. The wing clamping mold is fixed to the operating plane on the top of the main base 20 of the testing platform via a clamping device (not shown in the figure). The wing clamping mold has a square structure and is made of stainless steel or high-strength aluminum alloy, and is provided with an extended airfoil molding hole 11. The airfoil molding hole 11 is a through hole that runs longitudinally through the wing clamping mold along the main base 20 of the testing platform, and completely fits the airfoil section at the wing root after the flexible wing test piece 3 is filled with air, for clamping and fixing the flexible wing test piece 3. The top surface of the wing clamping mold is provided with regularly arranged through slots; the through slots are connected to the airfoil molding hole 11, for placing the air nozzle when the flexible wing test piece 3 is clamped in the wing clamping mold, to prevent the air nozzle from being excessively squeezed by the wing clamping mold, causing air blockage or damage.

[0030] Two supporting main beams 12 are symmetrically arranged on both sides of the wing clamping mold. The two supporting main beams 12 are arranged vertically and fixedly installed on the operating plane of the main base 20 of the test bench. Both the supporting main beams 12 and the supporting crossbeams 13 are square beam structures made of high-strength manganese alloy steel. Multiple light-reducing circular holes are opened on the supporting main beams 12, and the multiple light-reducing circular holes can be evenly distributed along the height of the supporting main beams 12, that is, the light-reducing circular holes are equidistantly arranged; the light-reducing circular holes are used to pass through the crossbeam fixing rods 15 to fix the supporting crossbeams 13. The supporting crossbeams 13 span between the two supporting main beams 12 and are fixed to the two supporting main beams 12 by the crossbeam fixing rods 15 passing through the light-reducing circular holes of the two supporting main beams 12. The supporting crossbeams 13 are provided with pull rope tethering protrusions 14 for tethering one end of the pull rope 101; the other end of the pull rope 101 is tied to the handle on the wing surface. By passing the crossbeam fixing rod 15 through the relief holes at different heights on the supporting main beam, the height of the supporting crossbeam 13 can be changed, thereby changing the height of the tie point of the pull rope 101. Since the stiffness of the flexible wing test piece 3 is determined by the preload of the pull rope 101, the height of one end of the pull rope 101 tied to the pull rope tie protrusion 14 will significantly affect the preload and load-bearing capacity of the pull rope 101. By passing the crossbeam fixing rod 15 through the relief holes at different heights on the supporting main beam 12, the height of the supporting crossbeam 13 and the pull rope tie protrusion 14 on it can be changed, thus enabling static strength tests of the flexible wing test piece 3 under different stiffnesses.

[0031] Example 2 like Figure 1 As shown, this embodiment provides a method for equivalent loading test of static strength of a lightweight wing. This test method is based on a flexible wing static strength test bench and includes the following steps: Step 1, Aerodynamic Load Calculation: Based on the typical operating conditions of the flexible wing aircraft, the aerodynamic load distribution of the flexible wing is calculated using computational fluid dynamics methods, the aerodynamic load data is extracted, and the data chain of the distribution along the wing surface for each operating condition is output.

[0032] Step 2, Load Zoning and Equivalent Calculation: The aerodynamic distributed load under typical operating conditions is zoned, dividing the flexible airfoil test piece 3 into multiple regions. Aerodynamic load data is organized, and the aerodynamic load of each region is calculated and equivalently converted into a concentrated load. The aerodynamic center of gravity position of each region is then calculated. For example... Figure 5A and Figure 5B As shown, in this embodiment, the flexible wing test piece 3 is divided into 5 regions, namely partition 1, partition 2, partition 3, partition 4 and partition 5. Partition 1 has an equivalent pressure center 11, partition 2 has an equivalent pressure center 12, partition 3 has an equivalent pressure center 13, partition 4 has an equivalent pressure center 14, and partition 5 has an equivalent pressure center 15.

[0033] Step 3, Test stand installation and clamping: Prepare a wing clamping mold according to the wing surface shape of the flexible wing test piece 3. Clamp the flexible wing test piece 3 with the wing clamping mold and fix the wing clamping mold on the top operating plane of the base 2. Tie one end of the pull rope 101 to the top of the static strength test stand 1 and the other end to the wing surface of the flexible wing test piece 3. Input high-pressure gas into the flexible wing test piece 3. When the gas pressure inside the flexible wing test piece 3 reaches the predetermined test value, the inflation and pressure holding are completed. Adjust the position of the flexible wing test piece 3 and the length of the pull rope 101 to complete the adjustment of the final test state of the flexible wing test piece 3.

[0034] The above-mentioned test bench installation and clamping steps also include: vertically installing a high-strength support beam 12 on each side of the wing clamping mold on the operating plane at the top of the base 2, the height of which is determined according to the actual stiffness of the flexible wing test piece 3. A support crossbeam 13 is erected and spans the two support beams 12, and is fixed to the support beams 12 by a through crossbeam fixing rod 15. A pull rope attachment protrusion 14 above the support crossbeam 13 is used to attach one end of a pull rope 101, and the other end of the pull rope 101 is attached to a handle on the wing surface of the flexible wing test piece 3. By passing the crossbeam fixing rod 15 through the lightening round holes at different heights of the support beams, the height of the support crossbeam 13 can be changed, thereby changing the height of the pull rope 101 attachment point and altering the test stiffness of the flexible wing test piece 3. Initially, the flexible wing test piece 3 is not inflated. A section (approximately 200mm~600mm) at the wing root of the flexible wing test piece 3 is placed inside the airfoil molding hole 11, with the wing root aligned with the end of the airfoil molding hole 11. Then, high-pressure gas is introduced into the flexible wing test piece 3 through the inflation device and gas supply pipeline via the air nozzle. Inflation is completed and pressure is maintained once the air pressure reaches the predetermined test value. The position of the flexible wing test piece 3 and the length of the pull rope 101 are adjusted to complete the final test state adjustment of the flexible wing test piece 3. When it is necessary to test both the left and right wings, the tension of the pull rope 101 needs to be adjusted to ensure that the left and right wings are in a state of symmetrical or asymmetrical stiffness to test the static strength under different working conditions.

[0035] Step 4, Equivalent Loading of Counterweights: Based on the partitioning of the flexible wing test piece 3 in Step 2, design the corresponding loading counterweight mass and distribution pattern for each region to ensure that the loaded weight is consistent with the concentrated force of the aerodynamic load, the position of the center of mass after loading is consistent with the center of pressure of the aerodynamic load, and the resultant moment after loading is consistent with the resultant moment of the aerodynamic load. The flexible loading counterweight module 301 is composed of several loading lead block units 501 connected in series by lead block connecting chains 502; the flexible loading counterweight module 301 is distributed along the spanwise direction of the flexible wing test piece 3; the loading lead block units 501 are arranged along the chordwise direction of the flexible wing test piece 3.

[0036] Several sets of flexible loading counterweight units are arranged according to the corresponding partitions of the flexible wing test piece 3. The total mass and center of gravity of the arranged flexible loading counterweight modules 301 coincide with the calculated aerodynamic equivalent load and equivalent pressure center position, thus completing the equivalent loading of the flexible wing test piece 3. When a single layer of flexible loading counterweight modules 301 covering the surface of the flexible wing test piece 3 is insufficient to achieve the equivalent aerodynamic load, static strength testing of the flexible wing test piece 3 under heavy load conditions can be achieved by using stacked flexible loading counterweight modules 301.

[0037] Step 5, Static Strength and Bending / Torsion Stiffness Measurement: Multiple displacement gauges 201 are set up on the ground directly below the flexible wing test piece 3. The displacements of the flexible wing test piece 3 at different positions after loading are measured by the multiple displacement gauges 201, and the equivalent stiffness of the flexible wing test piece 3 is preliminarily calculated by the stiffness conversion formula. When the flexible loading counterweight module 301 is uniformly loaded along the chord direction of the flexible wing test piece 3, and the load centers of each region are kept collinear along the spanwise direction of the flexible wing test piece 3, the static strength and stiffness limit test of the flexible wing test piece 3 under bending conditions can be achieved. When the flexible loading counterweight module 301 is linearly loaded along both ends of the chord direction of the flexible wing test piece 3, the static strength and stiffness limit test of the flexible wing test piece 3 under torsion conditions can be achieved.

[0038] The equivalent loading method using the above-described counterweight was employed to complete the equivalent loading of the flexible wing test specimen 3 under typical working conditions. A varying number of displacement gauges 201 were installed at specific locations on the ground directly below the flexible wing test specimen 3 to measure displacement at different positions after each loading cycle. The equivalent stiffness of the flexible wing test specimen 3 can be preliminarily calculated using the stiffness conversion formula.

[0039] By uniformly loading the flexible wing test piece 3 along the chord direction of the flexible wing test piece 3 using the flexible loading counterweight module 301, and keeping the load center of each region collinear with the spanwise direction of the flexible wing test piece 3, the static strength and stiffness limit tests of the flexible wing test piece 3 under bending conditions can be completed. Similarly, by linearly loading the flexible loading counterweight module 301 along both ends of the chord direction of the flexible wing test piece 3, the static strength and stiffness limit tests of the flexible wing test piece 3 under torsional conditions can be completed.

[0040] Step Six: Record Test Results: Record the weight, center of mass of the flexible loading counterweight module 301, and the displacement of the flexible wing test piece 3 at the monitoring position under each test condition. The final calculation of static strength and stiffness is completed using conversion formulas. The displacement gauge 201 can measure the displacement of the flexible wing test piece 3 before and after loading at different positions, and can also record the displacement of the flexible wing test piece 3 at different positions before and after loading.

[0041] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

[0042] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. 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 method for equivalent loading test of static strength of a lightweight wing, characterized in that, This test method is based on a static strength test bench for flexible wings. The static strength test bench includes a base, a static strength test platform, a pull rope, a displacement gauge, and a flexible loading counterweight module. The bottom of the base is fixedly installed on the ground to support the static strength test platform. The static strength test platform is fixedly installed on the top of the base. A wing clamping mold for holding and fixing the flexible wing test piece is provided at the bottom of the static strength test platform. The pull rope connects the static strength test platform and the wing surface of the flexible wing test piece, and the preload of the pull rope controls the stiffness of the flexible wing test piece. The flexible loading counterweight module is used to apply counterweight to the flexible wing test piece to achieve static strength testing. The displacement gauge is arranged on the ground below the flexible wing test piece to measure the displacement of different positions of the flexible wing test piece before and after loading. This test method includes the following steps: Step 1: Calculate the aerodynamic load; Step 2, load zoning and equivalent calculation, specifically includes: dividing the aerodynamic distributed load under typical working conditions into load zoning, dividing the flexible airfoil test piece into multiple regions, organizing the aerodynamic load data, calculating the aerodynamic load of each zone based on the divided regions and converting it into an equivalent concentrated load, and calculating the aerodynamic pressure center position of each region. Step 3: Installation and clamping of the test stand; Step four, equivalent loading of counterweights, specifically includes: designing the loading counterweight mass and distribution pattern for the corresponding areas based on the partitions of the flexible wing test piece in Step two, so that the loaded weight is consistent with the concentrated force of the aerodynamic load, the position of the center of mass after loading is consistent with the center of pressure of the aerodynamic load, and the resultant moment after loading is consistent with the resultant moment of the aerodynamic load; the flexible loading counterweight module is composed of several loading lead block units connected in series by lead block connecting chains; the flexible loading counterweight module is distributed along the spanwise direction of the flexible wing test piece; the loading lead block units are arranged along the chordal direction of the flexible wing test piece; Step 5, static strength and bending / torsional stiffness measurement, specifically includes: setting up multiple displacement gauges on the ground directly below the flexible wing test piece; measuring the displacement of the flexible wing test piece at different positions after loading using multiple displacement gauges; and preliminarily calculating the equivalent stiffness of the flexible wing test piece using the stiffness conversion formula; when the flexible loading counterweight module is uniformly loaded along the chord direction of the flexible wing test piece, and the load centers of each region are kept collinearly distributed along the spanwise direction of the flexible wing test piece, the static strength and stiffness limit test of the flexible wing test piece under bending conditions can be achieved; when the flexible loading counterweight module is linearly loaded along both ends of the chord direction of the flexible wing test piece, the static strength and stiffness limit test of the flexible wing test piece under torsional conditions can be achieved. Step six: Record the test results.

2. The equivalent loading test method for static strength of a lightweight wing as described in claim 1, characterized in that, Step one specifically includes: calculating the aerodynamic load distribution of the flexible wing based on the typical operating conditions of the flexible wing aircraft, extracting the aerodynamic load data, and outputting the data chain of the distribution along the wing surface for each operating condition.

3. The equivalent loading test method for static strength of a lightweight wing as described in claim 2, characterized in that, Step three specifically includes: preparing a wing clamping mold according to the wing surface shape of the flexible wing test piece; clamping the flexible wing test piece with the wing clamping mold and fixing the wing clamping mold on the top operating plane of the base; tying one end of the pull rope to the top of the static strength test platform and the other end to the wing surface of the flexible wing test piece; inputting high-pressure gas into the flexible wing test piece; completing the inflation and pressure holding process when the gas pressure inside the flexible wing test piece reaches the predetermined test value; adjusting the position of the flexible wing test piece and the length of the pull rope to complete the final test state adjustment of the flexible wing test piece.

4. The equivalent loading test method for static strength of a lightweight wing as described in claim 3, characterized in that, Step six specifically includes: recording the weight of the flexible loading counterweight module, the center of mass, and the displacement of the flexible wing test piece at the monitoring position under each test condition, and completing the final calculation of static strength and stiffness through conversion formulas.

5. A flexible wing static strength test bench for the equivalent loading test method for the static strength of a lightweight wing as described in claim 4, characterized in that, The base includes a test bench main base, a side stabilization frame, and a ground stabilization frame; The main base of the test bench is located directly below the wing clamping mold. It is a box-beam structure made of high-strength steel and is fixed to the ground of the test area by bolts. The side stabilization frame is welded to both sides of the main base of the test bench to enhance the lateral stability of the main base of the test bench; both the side stabilization frame and the ground stabilization frame are triangular truss structures; the ground stabilization frame is welded to both sides of the side stabilization frame and fixed to the ground to enhance the longitudinal stability of the main base of the test bench. The flexible loading counterweight module is composed of several loading lead block units connected in series by lead block connecting chains; the flexible loading counterweight module is distributed along the spanwise direction of the flexible wing test piece; the loading lead block units are arranged along the chordwise direction of the flexible wing test piece.

6. The static strength test bench for flexible wings as described in claim 5, characterized in that, The static strength test bench also includes a supporting main beam, a supporting crossbeam, a rope tethering contact point, and a crossbeam fixing rod; The wing clamping mold is fixed on the operating plane on the top of the main base of the test bench by a clamping device; the wing clamping mold is a square structure made of stainless steel or high-strength aluminum alloy and is provided with airfoil molding holes; the airfoil molding holes are through holes that penetrate the wing clamping mold and are completely fitted with the airfoil section at the wing root after the flexible wing test piece is filled with air, for clamping and fixing the flexible wing test piece; The top surface of the wing clamping mold is provided with regularly arranged through slots; the through slots are connected to the airfoil mold mounting holes and are used to place air nozzles when the flexible wing test piece is clamped in the wing clamping mold, so as to prevent the air nozzles from being excessively squeezed by the wing clamping mold, causing air blockage or damage. Two main support beams are symmetrically arranged on both sides of the wing clamping mold, and the two main support beams are fixedly installed on the operating plane of the main base of the test bench; both the main support beams and the crossbeams are square beam structures made of high-strength manganese alloy steel; the main support beams are provided with multiple relief holes, which are used to pass through the crossbeam fixing rods to fix the crossbeams; the crossbeams span between the two main support beams and are fixed to the two main support beams by the crossbeam fixing rods passing through the relief holes in the two main support beams; the crossbeams are provided with a pull rope tethering protrusion for tying one end of the pull rope; the other end of the pull rope is tied to a handle on the wing surface.

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