Strength testing tooling and testing method for composite cabin of UAV

Abstract

The present invention discloses a strength testing tool and testing method for a composite cabin for an unmanned aerial vehicle. The testing tool includes a cabin connecting plate, an end fixing device, a force adjustment device and a deformation measurement structure. The force adjustment device includes a unidirectional stress applying structure, a torsional stress applying structure and a force transmission structure, and the force transmission structure has a special-shaped force plate, a unidirectional stress transmission part and a torsional stress transmission assembly. In particular, a multiple linkage test structure is set up to realize the conversion of torsional torque to radial unidirectional pressure through geometric constraints and contact mechanics principles. The detection method adopts a step-by-step loading and multi-directional detection method to realize initial detection, face-changing detection and multi-directional comprehensive detection, and uses the displacement control mode to quickly reach the preset deformation variable using the qualified deformation value of the previous detection. The present invention can realize the bending moment and torque load detection in four directions of 0°, 90°, 180° and 270° in one clamping.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material detection, and in particular to a composite material cabin strength detection tool and a detection method for an unmanned aerial vehicle. Background Art

[0002] Drones need to be lighter, higher-strength and have good fatigue resistance, so composite materials, especially carbon fiber composites and glass fiber reinforced plastics (FRP), are widely used to manufacture key components such as the fuselage, wings and cabin of drones.

[0003] In order to ensure the quality and safety of drones before they leave the factory, strength testing of composite components is an essential step. However, existing testing technologies and equipment have many shortcomings in practical applications:

[0004] For example, the testing method is single and lacks comprehensiveness. Most existing testing equipment uses a single-direction load application method. For example, Chinese patent CN119023415A discloses "A UAV carbon fiber shell strength inspection device and its use method." While capable of testing the overall strength and localized strength of a UAV shell, it primarily relies on vertical pressure testing using a down-pressure head and a push rod, limiting its ability to detect lateral and torsional loads. This single-direction testing cannot fully assess the performance of composite components under complex stress conditions.

[0005] Similarly, although the "Device for Testing the Compressive Strength of a UAV Skeleton" disclosed in Chinese patent CN210626222U is equipped with three hydraulic mechanisms that can apply pressure to the sides and top of the UAV skeleton and can perform testing in three directions simultaneously, it is still limited to compression loads and lacks the ability to detect bending loads and torsional loads.

[0006] Low inspection efficiency and repeated clamping are prominent issues. Traditional inspection methods often require multiple re-clamping and repositioning of the inspected component to complete testing in different directions or with different load types. This repeated clamping not only consumes a significant amount of time and reduces inspection efficiency, but each re-clamping can also introduce new errors, affecting the consistency and accuracy of the test results. This is especially true for complex-shaped cabin components, where repeated clamping is even more difficult and positioning accuracy is even more challenging to ensure.

[0007] Furthermore, there is a lack of comprehensive testing capabilities for multiple load types. Composite cabins are subject to a variety of loads in actual use, including unidirectional bending moment and torsional loads. Existing technologies are mostly limited to testing a single load type and lack the ability to test multiple load types on the same equipment. This not only increases equipment investment costs but also prevents effective assessment of component strength characteristics under complex loads.

[0008] Therefore, it is necessary to develop a composite cabin bending moment load detection tooling that can achieve one-time clamping, multi-directional detection, multiple load types, high efficiency and high precision to meet the growing detection needs of UAV composite components. Summary of the Invention

[0009] The purpose of the present invention is to address the deficiencies of the prior art and provide a composite cabin strength testing tool and testing method for UAVs, which can achieve one-time clamping and multi-direction strength testing under multiple loads, significantly improving detection efficiency and accuracy.

[0010] In order to solve the above problems, the present invention adopts the following solutions:

[0011] A composite cabin strength testing tool for unmanned aerial vehicles, comprising:

[0012] Cabin connection plates are detachably connected to the two ends of the composite cabin, the shape of the cabin connection plates corresponds to the shape of the cabin ports, and the end surfaces are provided with a plurality of communication holes;

[0013] Support the work frame and stand it on the ground;

[0014] An end fixing device is installed on the supporting work frame and is used to fix the cabin body on the supporting work frame;

[0015] The force adjustment device is provided on the supporting work frame and is used to apply stress load to the cabin body, including: a unidirectional stress applying structure for applying a preset unidirectional stress; a torsional stress applying structure for applying torsional stress; and a force transmission structure as a transmission carrier for transmitting external stress to the cabin body;

[0016] Deformation measurement structure, used to detect the deformation of the cabin surface;

[0017] The force transmission structure includes: a special-shaped force-bearing plate having a central axis or a hole, which is detachably connected to the cabin connection plate, wherein the axis of the central axis or the hole is collinear with the central axis of the cabin; a unidirectional stress transmission member, which is connected and matched with the unidirectional stress applying structure; a torsional stress transmission component, which is connected and matched with the torsional stress applying structure;

[0018] Through the selective connection and coordination of the force transmission structure with the unidirectional stress applying structure and the torsional stress applying structure, the detection of different types of stress loads on the composite cabin can be achieved.

[0019] Furthermore, the unidirectional stress application structure includes: a first crossbeam frame, which can be detachably installed on the upper end of the supporting work frame; a display hanging scale, which is connected to the lower end of the first crossbeam frame through a connecting block and can display the applied stress value in real time; a stress adjustment structure, which cooperates with the display hanging scale to adjust the stress magnitude.

[0020] Furthermore, the torsional stress applying structure includes: a second crossbeam frame, which can be detachably installed on the upper end of the supporting work frame; a torque wrench, which is detachably connected to the force transmission structure and can directly display the torsional stress value applied by it; a torque adjustment structure, which is connected to the lower end of the second crossbeam frame and cooperates with the torque wrench to drive the torque wrench to rotate stably and in a small amplitude.

[0021] Furthermore, the torsional stress transmission component includes: a connecting chuck, which can be detachably connected to the torque wrench; two torque plug-ins, which are formed at both ends of the diameter of the connecting chuck and are arranged toward the cabin connecting plate; the special-shaped force-bearing plate has at least two opposing and outwardly protruding arc-shaped side walls, and each arc-shaped side wall is provided with a force-bearing surface at its connection point. The two torque plug-ins can respectively abut against the two force-bearing surfaces to generate a push, thereby applying torsional stress to the cabin.

[0022] Furthermore, it also includes a multiple linkage test structure, which cooperates with the torsional stress applying structure, including: a stress transfer column, which is arranged on the connecting chuck and faces the special-shaped force-bearing plate, and is used to transfer the torsional torque; a stress adjustment plate, which has an inclined surface at a specific angle and is fixedly arranged at one end of the stress transfer column close to the special-shaped force-bearing plate; a stress adjustment wheel, which can rotate freely and is axially fixedly connected to the edge of the special-shaped force-bearing plate, and its arc surface forms a tangential contact with the inclined surface of the stress adjustment plate.

[0023] Furthermore, the special-shaped stress-bearing plate is centrally symmetrically arranged, the arc-shaped side wall is provided with four sides, and four stress adjustment wheels are provided and are respectively located between each adjacent arc-shaped side wall.

[0024] The present invention also provides a composite material cabin strength testing method using the above-mentioned testing tool, comprising the following steps:

[0025] S1. Cabin installation: The composite cabin is fixed to the inspection fixture through the cabin connecting plate, and one end is fixed to the supporting work frame through the end fixing device;

[0026] S2. Initial Inspection: Apply a predetermined bending moment load to the other end of the cabin through the force adjustment device. The deformation measurement structure monitors the deformation of the loaded end of the cabin in real time to ensure that the deformation is within the qualified target range. At the same time, visually inspect the integrity of the interior and exterior surfaces of the cabin.

[0027] S3, face-changing test: When the initial direction test is qualified, the execution part of the load fixture is rotated 90°, and the qualified deformation value recorded in the previous test is used as the displacement control target, and a bending moment load is applied to the same end of the cabin in the new direction;

[0028] S4. Comprehensive multi-directional testing: Perform four 90° rotation tests in sequence according to the method in step S3 to achieve a comprehensive assessment of the bending moment strength of the cabin in the four directions of 0°, 90°, 180°, and 270°.

[0029] Furthermore, the initial inspection in step S2 specifically includes: S21, applying a unidirectional bending moment load to the cabin through a unidirectional stress applying structure, and facilitating the adjustment of the stress magnitude by displaying the stress value in real time; S22, monitoring the deformation of the cabin through a deformation measurement structure, and recording the deformation value when the qualified stress is reached; S23, visually inspecting whether there are defects such as cracks and delamination on the surface of the cabin.

[0030] Furthermore, the face-changing detection in step S3 adopts a displacement control mode, specifically: the qualified deformation value recorded in step S2 is used as the displacement control target, and the same deformation value is quickly achieved by controlling the rotation angle of the force transmission structure, thereby avoiding the iterative process of re-loading force-deformation measurement.

[0031] Furthermore, in the multi-directional comprehensive detection, multi-directional stress testing is achieved in the following manner: the connection between the second crossbeam frame and the supporting working frame is loosened, and the second crossbeam frame is moved along the supporting working frame so that it drives the torsional stress application structure to separate from the force transmission structure; the connecting chuck is rotated and reversed so that the stress adjustment plate on it corresponds to the stress adjustment wheel in other directions; the second crossbeam frame is re-installed to the appropriate position and the detection operation is repeated.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] Detection efficiency is significantly improved: the composite cabin only needs to be installed and fixed once to complete bending moment load detection in multiple directions, which greatly improves detection efficiency and reduces the errors and time costs caused by repeated clamping.

[0034] Multi-directional comprehensive testing: Through the multiple linkage test structure, it is possible to fully evaluate the bending moment strength of the cabin in the four directions of 0°, 90°, 180°, and 270°, ensuring the comprehensiveness and reliability of the test.

[0035] Displacement control mode: The displacement control mode is used for face-changing inspection. The qualified deformation value recorded in the previous inspection is used as the control target. The preset deformation value can be quickly achieved, which significantly improves the inspection efficiency.

[0036] High detection accuracy: The stress value is displayed in real time through the display crane scale, and the deformation measurement structure accurately monitors the deformation amount to ensure the accuracy and reliability of the test results.

[0037] Strong applicability: The inspection tooling can be applied to composite cabins of different shapes, including special-shaped cylindrical structures and cylindrical structures, and has good versatility.

[0038] Rich stress types: It can perform unidirectional stress and torsional stress testing simultaneously, comprehensively evaluate the mechanical properties of the cabin, and meet different testing needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic structural diagram of a composite cabin according to the present invention;

[0040] Figure 2 This is a schematic structural diagram of another composite cabin of the present invention;

[0041] Figure 3 This is a partial structural diagram of the cabin detection method of the present invention;

[0042] Figure 4 This is a partial structural schematic diagram of the unidirectional stress applying structure of the present invention when it is installed on the supporting work frame;

[0043] Figure 5 This is a partial structural schematic diagram of the torsional stress applying structure of the present invention when it is installed on the supporting work frame;

[0044] Figure 6 A schematic structural diagram of a torsional stress applying structure according to the present invention;

[0045] Figure 7 for Figure 6 A partial enlarged view of point Ⅰ in the middle;

[0046] Figure 8 It is a structural schematic diagram of the force transmission structure of the present invention;

[0047] Figure 9 A schematic plan view of the invention showing that only the multiple linkage test structure generates unidirectional stress on the special-shaped load-bearing plate;

[0048] Figure 10 This is a planar schematic diagram of the present invention in which only the torque plug-in unit transmits torsional stress to the special-shaped load-bearing plate;

[0049] Figure 11 A schematic structural diagram of a cross-section of the cabin body of the present invention;

[0050] Figure 12 This is a schematic diagram of the structure of the installation and fixing device of the present invention when it is disassembled;

[0051] Figure 13 This is a schematic diagram of the bending moment load detection process;

[0052] Figure 14 Schematic diagram of the multiple linkage test process.

[0053] Figure numerals: cabin 01, threaded through hole 02, supporting work frame 10, mounting and fixing device 20, force adjustment device 30, deformation measurement structure 40, sealing detection structure 50, cabin connecting plate 21, quick lock 22, fixing plate 23, unidirectional stress applying structure 31, torsional stress applying structure 32, force transmission structure 33, multiple linkage test structure 34, universal adjustment bracket 41, runout dial indicator 42, detection lamp 51, adjustment mounting frame 52, first through hole 53, second through hole 54, connecting hole 211, first crossbeam frame 311, displayable hanging scale 312, stress adjustment structure 313, connection block 31 4. Second crossbeam 321, torque wrench 322, torque adjustment structure 323, special-shaped force-bearing plate 331, unidirectional stress transmission member 332, torsional stress transmission assembly 333, support stabilization plate 334, stress transmission column 341, stress adjustment plate 342, stress adjustment wheel 343, hook 3121, threaded hole 3131, operating screw 3132, motor 3231, screw 3232, adjustment slider 3233, operating wheel 3234, movable push-rotating member 3235, limiting space 3236, curved side wall 3311, force-bearing surface 33111, hanging ring 3321, connecting chuck 3331, torque plug-in 3332. DETAILED DESCRIPTION

[0054] Example: This example is used to detect the strength characteristics of the composite material cabin 01 under stress.

[0055] The composite cabin 01 is made of glass fiber reinforced plastic (FRP), with metal parts embedded in some areas to enhance structural strength. Based on actual usage requirements, the specific structural forms of cabin 01 mainly include the following:

[0056] 1. As Figure 1 The special-shaped cylindrical structure shown: This structure is a symmetrical cylindrical body with both ends connected. The overall shape is rectangular, and the shapes and sizes of the end faces at both ends are different.

[0057] 2. If Figure 2 The cylindrical structure shown: This structure is also a cylinder with both ends connected, but the shapes and sizes of the end faces at both ends are the same, both are circular.

[0058] In order to achieve reliable connection between the cabin and the detection equipment, no matter which structural form is adopted, the outer peripheral wall of the end of the cabin 01 is provided with multiple threaded through holes 02 for achieving reliable connection and fixation with other components of the drone.

[0059] Based on the above cabin structure characteristics, this embodiment provides a strength testing tool for testing the composite cabin 01 for the above drone. The tool adopts a step-by-step loading and multi-directional testing method. The specific testing process is as follows:

[0060] Initial testing: When performing a bending moment load test on the composite cabin 01, one end of the cabin 01 is first securely fixed with a fixture, and then a predetermined bending moment load is applied to the other end. A deformation detection device monitors the deformation of the loaded end of the cabin 01 in real time to ensure that the deformation is within the acceptable target range. Simultaneously, the integrity of the interior and exterior surfaces of the cabin 01 is visually inspected for defects such as cracks and delamination.

[0061] Re-surface Inspection: After the initial orientation inspection passes (i.e., deformation is within the allowable range and there are no surface defects), re-surface inspection is performed. Specifically, the actuating portion of the load fixture is rotated 90°. Using the qualified deformation value recorded from the previous inspection as the displacement control target, a bending moment load is applied to the same end of cabin 01 in the new orientation. The displacement control mode allows the preset deformation to be achieved quickly, significantly improving inspection efficiency. After achieving the target deformation, the cabin surface integrity is re-inspected to determine if the strength in that orientation meets the requirements.

[0062] Comprehensive multi-directional testing: Perform four 90° rotation tests in sequence according to the above method to achieve a comprehensive assessment of the bending moment strength of cabin 01 in the four directions of 0°, 90°, 180°, and 270°.

[0063] Detection advantages: The advantage of using this detection method is that the composite cabin 01 only needs to be installed and fixed once to complete the bending moment load detection in multiple directions, which greatly improves the detection efficiency and reduces the error and time cost caused by repeated clamping.

[0064] In order to implement the above detection method, refer to Figure 2 and Figure 3 The bending moment load detection tooling includes: a cabin connecting plate 21 detachably connected to both ends of the cabin 01; a supporting work frame 10 standing on the ground; an end fixing device 20 installed on the supporting work frame 10; a force adjustment device 30 provided on the supporting work frame 10; and an independently configured deformation measurement structure 40.

[0065] The cabin connecting plate 21 serves as the interface between the tooling and the cabin. Its shape corresponds to the port shape of the cabin 01. It has multiple screw holes on its circumference and multiple connecting holes 211 on its end. The screw holes are used to mate with the threaded through holes 02 at the end of the cabin 01 to achieve a fixed connection. The connecting holes 211 are used to secure the end surface or connect to the force adjustment device 30.

[0066] The end fixing device 20 is responsible for the cabin installation and fixing function, refer to Figure 3 , used to securely mount the pod 01 on the support frame 10, and includes quick-release fasteners 22 and a fixing plate 23 connected to the support frame 10. Multiple quick-release fasteners 22 enable quick connection or removal of the pod connecting plate 21 and the fixing plate 23, thereby securing the pod 01 to the support frame 10. The quick-release fasteners 22 are optional fasteners well known to those skilled in the art, and ordinary bolts can also be used as an alternative.

[0067] The force adjustment device 30 is the core design of this detection tool. Figure 3-Figure 4 , used to apply stress load to the cabin 01 and realize the face-changing detection function, including a unidirectional stress applying structure 31, used to apply preset unidirectional stress to detect whether the deformation characteristics of the cabin 01 meet the requirements; a torsional stress applying structure 32, used to apply torsional stress to detect the strength characteristics of the cabin 01; a force transmission structure 33, as a transmission carrier for transmitting external stress to the cabin 01, is connected to the cabin connecting plate 21 through a quick locker 22, and cooperates with the unidirectional stress applying structure 31 and the torsional stress applying structure 32.

[0068] The unidirectional stress applying structure 31 is responsible for applying a controllable unidirectional load. Figure 4 , including: a first crossbeam frame 311, which serves as a support and installation carrier of this structure and can be detachably installed on the upper end of the supporting work frame 10; a display hanging scale 312, which is connected to the lower end of the first crossbeam frame 311 through a connecting block 314 and can display the applied stress value in real time; a stress adjustment structure 313, which cooperates with the display hanging scale 312 to adjust the stress size.

[0069] In order to achieve precise force control, the lower end of the display hanging scale 312 has a hook 3121 that cooperates with the force transmission structure 33; the stress adjustment structure 313 adopts a threaded structure, including an operating screw 3132, and the operating screw 3132 passes through the first crossbeam frame 311 and the threaded hole 3131 of the connecting block 314. Therefore, stress adjustment can be achieved by rotating the operating screw 3132 and adjusting the thread pre-tightening force until the value displayed on the display hanging scale 312 reaches the preset value.

[0070] The torsional stress applying structure 32 is specifically used to apply torsional loads. Figure 5-Figure 6 , including: a second crossbeam 321, which serves as a support and installation carrier for the torsional stress applying structure 32 and can be detachably installed on the upper end of the supporting work frame 10; a torque wrench 322, which is detachably connected to the force transmission structure 33 and can directly display the torsional stress value applied by it; a torque adjustment structure 323, which is connected to the lower end of the second crossbeam 321 and cooperates with the torque wrench 322 to stably and slightly drive the torque wrench to rotate to ensure the reliability of the detection.

[0071] The torque adjustment structure 323 adopts a screw structure, including a motor 3231, a screw 3232, an adjustment slider 3233, and an operating wheel 3234. The motor 3231 and the operating wheel 3234 are respectively connected to the upper and lower ends of the screw 3232. The adjustment slider 3233 is threadedly connected to the screw 3232. The adjustment slider 3233 is also provided with a movable push-rotating member 3235 with a limited space 3236, through which the torque wrench 322 passes. With this structural design, the screw 3232 can be driven to rotate by the motor 3231 or the operating wheel 3234, thereby driving the adjustment slider 3233 and the movable push-rotating member 3235 connected thereto to move up and down. The movable push-rotating member 3235 not only drives the torque wrench 322 to move up and down, but also causes it to move left and right along the limited space 3236, thereby achieving rotation of the torque wrench 322 and applying torsional stress to the cabin 01.

[0072] The design advantage of this torsional stress applying structure 32 is that it allows for smooth and stable torque changes, ensuring test reliability. Furthermore, for a single torsional stress test, manual control of the operating wheel 3234 is sufficient, saving time, effort, and resources. For repeated torsional stress tests, the motor 3231 can be activated for repeated testing, improving test efficiency while ensuring test results.

[0073] The force transfer structure 33 is the key link of load transfer, refer to Figure 6 , including: a special-shaped force-bearing plate 331 with a central axis, which is detachably connected to the cabin connecting plate 21 through a quick lock, and its central axis is collinear with the central axis of the cabin 01; a unidirectional stress transmission part 332, connected and cooperated with the unidirectional stress applying structure 31; a torsional stress transmission component 333, connected and cooperated with the torsional stress applying structure 32.

[0074] refer to Figure 4 The unidirectional stress transmission component 332 adopts a hanging ring 3321, which is arranged at the center of the special-shaped stress-bearing plate 331, for example, connected to the central axis of the special-shaped stress-bearing plate 331, and is used to realize hanging cooperation with the hook 3121 that can display the hanging scale 312, thereby realizing the stress transmission from the unidirectional stress applying structure 31 to the cabin 01.

[0075] The torsional stress transmission component 333 is responsible for the transmission function of the torsional load. Figure 6 、 Figure 8, which cooperates with the special-shaped force-bearing plate 331, includes: a connecting chuck 3331, which is detachably connected to the torque wrench 322; and two torque plugs 3332, formed at both ends of the diameter of the connecting chuck 3331 and arranged toward the cabin connection plate 21. The special-shaped force-bearing plate 331 has at least two opposing and outwardly convex arcuate side walls 3311. Each arcuate side wall 3311 is provided with a force-bearing surface 33111 at its head and tail. The two torque plugs 3332 can respectively abut against the two force-bearing surfaces 33111 to generate a push, thereby applying torsional stress to the cabin 01.

[0076] The working process of torsional stress transmission is as follows: rotate the torque wrench 322 so that it drives the two torque plug-ins 3332 to rotate through the connecting chuck 3331, and the torque plug-in 3332 rotates along the arc-shaped side wall 3311, pushing the force surface 33111 at the connection of the arc-shaped side wall 3311, so that the extrusion stress between the torque plug-in 3332 and the force surface 33111 gradually increases, and the gradually increasing thrust formed by the extrusion stress drives the special-shaped force plate 331 to generate a rotation trend, thereby generating a bending moment and transmitting it to the cabin 01.

[0077] To ensure stable and reliable torque transmission, refer to Figure 5 A supporting stabilizing plate 334 connected to the second crossbeam 321 is provided, which has a mounting hole that rotates closely with the central axis of the connecting chuck 3331 to support the connecting chuck 3331 and ensure the stable rotation of the connecting chuck 3331.

[0078] Multiple linkage test structure 34, reference Figure 6-Figure 8 , which cooperates with the torsional stress applying structure 32, including: a stress transfer column 341: arranged on the connecting chuck 3331 and facing the special-shaped force-bearing plate 331, for transmitting unidirectional torque; a stress adjustment plate 342: having an inclined surface with a specific angle, fixedly arranged on one end of the stress transfer column 341 close to the special-shaped force-bearing plate 331; a stress adjustment wheel 343: freely rotatable, axially fixedly connected to the edge of the special-shaped force-bearing plate 331, and its arc surface forms a tangential contact with the inclined surface of the stress adjustment plate 342.

[0079] The core technical principle of the multi-link test structure 34 is to convert the rotational torque of the connecting chuck 3331 into radial unidirectional pressure on the special-shaped load-bearing plate 331 through geometric constraints and contact mechanics principles:

[0080] 1. Initial contact state: The arc surface of the stress adjustment wheel 343 and the inclined surface of the stress adjustment plate 342 form tangential contact at a specific point, and the normal force at the contact point is perpendicular to the tangential direction.

[0081] 2. Force Decomposition and Transmission: When the connecting chuck 3331 generates a torsional torque, the torque is transmitted to the stress adjustment plate 342 via the stress transfer column 341. Due to the geometric constraints of the inclined surface, the force acting on the contact point can be decomposed into: a. a tangential component along the inclined surface (driving the wheel to roll); b. a normal component perpendicular to the inclined surface (generating a squeezing effect).

[0082] 3. Motion Conversion Process: Under the constraint of the inclined plane, the stress-adjusting wheel 343 rolls from the lower end to the upper end. During this rolling process, the vertical displacement of the wheel center is Δh = r·θ·sin(α) (where r is the wheel radius, θ is the rotation angle, and α is the inclined plane angle). Due to the rigid connection between the wheel and the shaped load-bearing plate 331, the plate undergoes a corresponding radial displacement. This displacement, under the constraint of the plate, is converted into a unidirectional compressive stress on the cabin 01.

[0083] The structure has a unique two-stage working mode:

[0084] Phase I Figure 9 As shown): The torque plug 3332 is located at the bottom end of the arc-shaped side wall 3311, and the stress adjustment plate 342 and the stress adjustment wheel 343 remain separated (gap δ > 0). At this stage, pure torsional torque is applied to the special-shaped load-bearing plate 331 only through the contact between the torque plug 3332 and the load-bearing surface 33111.

[0085] Phase II Figure 10 As shown in FIG3 ): The torque plug-in 3332 rotates in the opposite direction relative to the first stage, separating the torque plug-in 3332 from the force-bearing surface 33111. The lower end of the inclined surface of the stress adjustment plate 342 makes tangential contact with the stress adjustment wheel 343. When the rotation continues, the stress adjustment wheel 343 rolls upward along the inclined surface, generating a radial extrusion force: F = P·cos(α) (where P is the total force at the contact point and α is the inclined surface angle). This radial force is transmitted to the edge of the cabin 01 through the special-shaped force-bearing plate 331, forming a unidirectional compressive stress.

[0086] Reference Figure 11-14 , as shown in the figure, the multi-linkage test structure has the following technical advantages: Stress mode switching: through clever geometric design, a smooth conversion from torsional stress to unidirectional compressive stress is achieved to avoid stress mutation. Force amplification effect: by utilizing the wedge principle of the inclined plane, a smaller torsional torque can be converted into a larger radial pressure, thereby improving the detection sensitivity. Multi-directional detection: by adjusting the angular position of the connecting chuck 3331, unidirectional stress can be applied to different directions of the special-shaped force-bearing plate 331 to achieve all-round strength detection. Precise displacement control: by controlling the torsion angle, the displacement of the stress adjustment wheel 343 on the inclined plane can be precisely controlled, thereby precisely controlling the magnitude of the applied unidirectional stress. Combined with real-time monitoring of the deformation measurement structure 40, rapid detection based on displacement control can be achieved.

[0087] The design of the multi-link test structure fully considers the process requirements of face-changing detection:

[0088] Implementation of the displacement control mode: During the initial direction detection, the cabin deformation variable δa when the qualified stress is reached is recorded through the deformation measurement structure 40. During the face-changing detection, the deformation variable δa is used as the displacement control target. By precisely controlling the rolling distance of the stress adjustment wheel 343 on the inclined surface, the same deformation variable is quickly achieved. The displacement control relationship is: δ = f(θ, α, r) = r·θ·sin(α)·K (where K is the system transfer coefficient).

[0089] Fast positioning mechanism: Using the known qualified deformation value, the required torsion angle θ target can be directly calculated, avoiding the iterative process of re-loading force and deformation measurement, significantly improving detection efficiency and reducing test time.

[0090] Multi-directional consistency assurance: Through a unified displacement control algorithm, the detection conditions in each direction (0°, 90°, 180°, 270°) are consistent, eliminating the systematic errors caused by repeated clamping and recalibration, and ensuring the comparability of multi-directional detection results.

[0091] To ensure system performance, key design parameter requirements are as follows:

[0092] Inclined surface angle α: should be determined according to the required force amplification factor, rolling stability and displacement control accuracy requirements, generally 15°-30°; stress adjustment wheel radius r: should match the inclined surface length and the expected deformation range to ensure that the effective working stroke covers the qualified deformation range; system transfer coefficient K: needs to be determined through calibration tests to establish an accurate correspondence between the torsion angle and the cabin deformation; contact surface treatment: should have appropriate surface roughness (Ra 1.6-3.2μm) to ensure rolling rather than sliding, and ensure the accuracy of displacement transmission; material strength: should meet the safety factor requirements under the maximum design load (≥2.5), while considering fatigue strength to adapt to multiple testing needs.

[0093] Preferably, reference Figures 8-10 The special-shaped stress-bearing plate 331 is centrally symmetrically arranged, with multiple stress adjustment wheels 343 provided thereon. The arcuate sidewall 3311 is provided with multiple faces, each facing each other. In this embodiment, the arcuate sidewall 3311 has four faces, and four stress adjustment wheels 343 are provided, one located between each adjacent arcuate sidewall 3311. Accordingly, the torque wrench 322 is driven by a square head at each corner.

[0094] Based on the above-mentioned multi-linkage structure design, the multi-directional edge unidirectional stress test of the multi-linkage test structure 34 can be realized without adjusting the posture of the cabin 01, which not only further enriches the diversity of strength testing but also ensures the testing efficiency. Figure 5 As shown, the bolts fixing the second crossbeam 321 and the supporting work frame 10 are loosened, and the crossbeam 321 is rolled along the supporting work frame 10 to drive the torsional stress applying structure 32 to separate from the force transmitting structure 33. Figure 6 , and then rotate the connecting chuck 3331 to reverse the direction so that the stress adjustment plate 342 on it corresponds to the stress adjustment wheel 343 in other directions, and then move the second beam frame 321 to the appropriate position again, and repeat the above-mentioned detection operation.

[0095] In order to accurately monitor the deformation response of the cabin, refer to Figure 4 The deformation measurement structure 40 is used to detect the deformation amount of the surface of the cabin body 01. Multiple groups can be set (only one group is shown in the figure). Each group includes a universal adjustment bracket 41 and a runout dial indicator 42. The runout dial indicator 42 is tightly attached to the surface of the cabin body 01. Its detection accuracy can be accurate to 0.001mm. The runout dial indicator 42 is detachably connected to the universal adjustment bracket 41. The universal adjustment bracket 41 adopts existing technology products and can achieve multi-directional adjustment.

[0096] After completing the mechanical performance test, in order to fully evaluate the quality of the cabin, refer to Figure 6 、 Figure 11 After applying torsional stress or unidirectional stress to the cabin 01 using the above-mentioned torsional stress applying structure 32, force transmission structure 33, and multi-linkage test structure 34, in order to facilitate the observation of whether there are more obvious cracks in the cabin 01, this detection tool is also equipped with a sealing detection structure 50. It uses the characteristic that light can pass through the cabin 01 made of fiberglass. By setting a light source in the middle of the cabin 01, the brightness is observed to determine whether there are cracks. If there is any doubt about the bright part, further sealing detection can be carried out on that part using proprietary equipment.

[0097] like Figure 11 As shown, the sealing detection structure 50 includes a detection lamp 51 and an adjustment mounting bracket 52. The detection lamp 51 is connected to the fixed plate 23 through the adjustment mounting bracket 52, and passes through the first through hole 53 of the fixed plate 23 and the second through hole 54 of the cabin connecting plate 21, extending the detection lamp 51 to the center position inside the cabin 01.

Claims

1. A composite cabin strength testing tool for UAV, characterized by: include: A cabin connecting plate (21) is detachably connected to both ends of the composite cabin (01); the shape of the cabin connecting plate (21) corresponds to the shape of the port of the cabin (01), and a plurality of communication holes (211) are provided on the end surface; A supporting work frame (10) is placed on the ground; An end fixing device (20) is mounted on the supporting work frame (10) and is used to fix the cabin (01) on the supporting work frame (10); A force regulating device (30) is provided on the supporting work frame (10) and is used to apply a stress load to the cabin (01), comprising: a unidirectional stress applying structure (31) for applying a preset unidirectional stress; a torsional stress applying structure (32) for applying torsional stress; and a force transmitting structure (33) as a transmitting carrier for transmitting external stress to the cabin (01); A deformation measuring structure (40) for detecting the deformation amount of the surface of the cabin (01); The force transmission structure (33) includes: a special-shaped force-bearing plate (331) having a central axis or a hole, which is detachably connected to the cabin connecting plate (21), wherein the axis of the central axis or the hole is collinear with the central axis of the cabin (01); the special-shaped force-bearing plate (331) has at least two opposing and outwardly convex arc-shaped side walls (3311), and each arc-shaped side wall (3311) is provided with a force-bearing surface (33111) at its connection; a unidirectional stress transmission member (332) connected and matched with the unidirectional stress applying structure (31); and a torsional stress transmission assembly (333) connected and matched with the torsional stress applying structure (32); The torsional stress transmission component (333) comprises: a connecting chuck (3331) which is detachably plugged into the torque wrench (322); Two torque plug-ins (3332) are formed at both ends of the diameter of the connecting chuck (3331) and are arranged toward the cabin connecting plate (21); the two torque plug-ins (3332) can respectively abut against the two force-bearing surfaces (33111) to generate a push, thereby applying a torsional stress to the cabin (01); The detection fixture also includes a multi-linkage test structure (34) that cooperates with the torsional stress applying structure (32), including: a stress transfer column (341), which is arranged on the connecting chuck (3331) and faces the special-shaped stress-bearing plate (331) and is used to transfer the torsional moment; a stress adjustment plate (342), which has an inclined surface and is fixedly arranged at one end of the stress transfer column (341) close to the special-shaped stress-bearing plate (331); a stress adjustment wheel (343), which can rotate freely and is axially fixedly connected to the edge of the special-shaped stress-bearing plate (331), and its arc surface forms a tangential contact with the inclined surface of the stress adjustment plate (342); By selectively connecting and cooperating the force transmission structure (33) with the unidirectional stress applying structure (31) and the torsional stress applying structure (32), detection of different types of stress loads on the composite material cabin (01) is achieved.

2. The composite cabin strength testing tool for UAV according to claim 1 is characterized in that: The unidirectional stress applying structure (31) comprises: A first crossbeam frame (311) is detachably mounted on the upper end of the supporting work frame (10); A display hanging scale (312) is connected to the lower end of the first crossbeam (311) via a connecting block (314); The stress regulating structure (313) cooperates with the displayable hanging scale (312) to regulate the stress magnitude.

3. The composite cabin strength testing tool for UAV according to claim 1 is characterized in that: The torsional stress applying structure (32) comprises: A second crossbeam frame (321) is detachably mounted on the upper end of the supporting work frame (10); A torque wrench (322) is detachably connected to the force transmission structure (33) and can directly display the value of the torsional stress applied by it; The torque adjustment structure (323) is connected to the lower end of the second crossbeam (321) and cooperates with the torque wrench (322) to drive the torque wrench to rotate stably and in a small amplitude.

4. The composite cabin strength testing tool for UAV according to claim 1 is characterized in that: The special-shaped stress-bearing plate (331) is centrally symmetrically arranged, and the arc-shaped side walls (3311) are symmetrically arranged in pairs around the center of the stress-bearing plate (331). Four stress adjustment wheels (343) are provided and are respectively located between each adjacent arc-shaped side wall (3311).

5. A testing method using the composite cabin strength testing tool for unmanned aerial vehicle according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Cabin installation: The composite cabin (01) is fixed on the inspection fixture via the cabin connecting plate (21), and one end is fixed on the supporting work frame (10) via the end fixing device (20); S2. Initial inspection: a predetermined bending moment load is applied to the other end of the cabin (01) through the force adjustment device (30), and the deformation of the loaded end of the cabin (01) is monitored in real time through the deformation measurement structure (40) to ensure that the deformation is controlled within the qualified target range, and at the same time, the integrity of the inner and outer surfaces of the cabin (01) is visually inspected; S3, face-changing test: when the initial direction test is qualified, the execution part of the load fixture is rotated 90 degrees, and the qualified deformation value recorded in the previous test is used as the displacement control target, and a bending moment load is applied to the same end of the cabin (01) in the new direction; S4. Comprehensive multi-directional testing: Carry out 4 90° rotation tests in sequence according to the method of step S3 to achieve a comprehensive assessment of the bending moment strength of the cabin (01) in the four directions of 0°, 90°, 180°, and 270°.

6. The detection method according to claim 5, characterized in that The initial detection in step S2 specifically includes: S21, applying a unidirectional bending moment load to the cabin (01) through the unidirectional stress applying structure (31), and facilitating adjustment of the stress magnitude by displaying the stress value in real time; S22, monitoring the deformation of the cabin (01) through the deformation measurement structure (40), and recording the deformation value when the qualified stress is reached; S23. Visually inspect the surface of the hull (01) for cracks and / or delamination defects.

7. The detection method according to claim 5, characterized in that The face change detection in step S3 adopts a displacement control mode, specifically: The qualified deformation value recorded in step S2 is used as the displacement control target, and the same deformation value is quickly achieved by controlling the rotation angle of the force transmission structure (33), avoiding the iterative process of re-doing the force loading-deformation measurement.

8. The detection method according to claim 5, characterized in that In the multi-directional comprehensive detection, multi-directional stress testing is achieved by the following methods: Loosening the connection between the torsional stress applying structure (32) and the supporting work frame (10), and moving the torsional stress applying structure (32) along the supporting work frame (10) so as to drive the torsional stress applying structure (32) to separate from the force transmitting structure (33); After the special-shaped load-bearing plate (331) is rotated and reversed, the second crossbeam frame (321) is moved and installed again to a suitable position, and the detection operation is repeated.

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