Strength detection tool and detection method of composite cabin for unmanned aerial vehicle

Abstract

The invention discloses a strength detection tool and method for a composite cabin for an unmanned aerial vehicle. The detection tool comprises a cabin connecting plate, an end fixing device, a force application adjusting device and a deformation measuring structure. The force application adjusting device comprises a one-way stress application structure, a torsional stress application structure and a stress transmission structure. The stress transmission structure is provided with a special-shaped stress plate, a one-way stress transmission piece and a torsional stress transmission assembly. Particularly, a multi-linkage test structure is arranged, and conversion from torsional moment to radial one-way pressure is realized through geometric constraint and contact mechanics principles. According to the detection method, a step-by-step loading and multi-direction detection mode is adopted, initial detection, surface change detection and multi-direction comprehensive detection are achieved, and the preset deformation quantity is rapidly achieved through a displacement control mode by means of the qualified deformation quantity value detected last time. According to the invention, bending moment and torque load detection in four directions of 0 degree, 90 degrees, 180 degrees and 270 degrees can be completed through one-time clamping.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material detection, and particularly to a strength detection tooling and detection method for a composite material cabin body of an unmanned aerial vehicle (UAV). Background Art

[0002] UAVs need to be more lightweight, have high strength and good fatigue resistance. Therefore, composite materials, especially carbon fiber composite materials and glass fiber reinforced plastics (FRP), are widely used in manufacturing key components such as the fuselage, wings and cabin bodies of UAVs.

[0003] To ensure the quality and use safety of UAVs before leaving the factory, strength detection of composite material components is an essential step. However, existing detection technologies and equipment have many deficiencies in practical applications: For example, the detection method is single and the comprehensiveness is insufficient. Most existing detection equipment adopts a single-direction load application method. For example, the "Strength Inspection Equipment and Its Use Method for a UAV Carbon Fiber Outer Shell" disclosed in Chinese Patent CN119023415A can detect the overall strength and local area strength of the UAV outer shell, but mainly conducts vertical pressing detection through a lower pressing head and a jack rod, and has limited detection ability for lateral and torsional loads. This single-direction detection cannot comprehensively evaluate the performance of composite material components under complex stress states.

[0004] Similarly, the "UAV Skeleton Compressive Strength Detection Device" disclosed in Chinese Patent CN210626222U is provided with three hydraulic mechanisms, which can apply pressure to both sides and the top of the UAV skeleton and can detect in three directions simultaneously, but it is still limited to compressive loads and lacks the detection ability for bending moment loads and torsional loads.

[0005] In addition, the detection efficiency is low and the problem of repeated clamping is prominent. Traditional detection methods usually require multiple re-clamping and positioning of the components to be detected to complete load detection in different directions or of different types. This repeated clamping not only consumes a large amount of time and reduces the detection efficiency, but also may introduce new errors each time of re-clamping, affecting the consistency and accuracy of the detection results. Especially for complex-shaped cabin body components, the difficulty of repeated clamping is greater and the positioning accuracy is more difficult to guarantee.

[0006] In addition, there is a lack of comprehensive detection ability for multiple load types. The composite material cabin body will bear various types of loads in actual use, including unidirectional bending moment loads, torsional loads, etc. Most existing technologies can only detect a single type of load and lack the ability to detect multiple load types on the same set of equipment. This not only increases the equipment investment cost, but also cannot effectively evaluate the strength characteristics of the components under combined loads.

[0007] Therefore, it is necessary to develop a bending load detection tooling for composite material cabin bodies that can achieve one-time clamping, multi-directional detection, multiple load types, high efficiency, and high precision to meet the increasing detection requirements of UAV composite material components. Summary of the Invention

[0008] The purpose of the present invention is to solve the deficiencies of the prior art and provide a strength detection tooling and detection method for composite material cabin bodies of UAVs, which can achieve strength detection of one-time clamping, multi-directional and multiple loads, and significantly improve the detection efficiency and precision.

[0009] To solve the above problems, the present invention adopts the following solutions: A strength detection tooling for composite material cabin bodies of UAVs, comprising: Cabin connection plates, detachably connected to both ends of the composite material cabin body. The shape of the cabin connection plates corresponds to the shape of the ports of the cabin body, and a plurality of communication holes are provided on the end faces. Support working frame, standing on the ground; End fixing device, installed on the support working frame for fixedly installing the cabin body on the support working frame; Force application and adjustment device, arranged on the support working frame for applying stress loads to the cabin body, including: unidirectional stress application structure for applying a preset unidirectional stress; torsional stress application structure for applying torsional stress; force transmission structure as a transmission carrier for transmitting external stress to the cabin body; Deformation measurement structure for detecting the amount of deformation on the surface of the cabin body; Wherein, the force transmission structure includes: a special-shaped force-bearing plate with a central axis or hole, detachably connected to the cabin connection plate, and the axis of its central axis or hole is collinear with the central axis of the cabin body; unidirectional stress transmission member, connected and cooperated with the unidirectional stress application structure; torsional stress transmission assembly, connected and cooperated with the torsional stress application structure; By selectively connecting and cooperating the force transmission structure with the unidirectional stress application structure and the torsional stress application structure, the detection of different types of stress loads on the composite material cabin body is realized.

[0010] Furthermore, the unidirectional stress application structure includes: a first crossbeam frame, detachably installed on the upper end of the support working frame; a visible hanging scale, connected to the lower end of the first crossbeam frame through a connecting block and capable of displaying the applied stress value in real time; a stress adjustment structure, cooperating with the visible hanging scale for adjusting the stress magnitude.

[0011] Furthermore, the torsional stress applying structure includes: a second cross beam frame detachably installed at the upper end of the support working frame; a torque wrench detachably connected to the force transmission structure and capable of directly displaying the value of the torsional stress it applies; a torque adjusting structure connected to the lower end of the second cross beam frame and cooperating with the torque wrench for stably driving the torque wrench to rotate in a small amplitude.

[0012] Furthermore, the torsional stress transmission assembly includes: a connecting chuck detachably inserted into the torque wrench; two torque inserts formed at both ends of the diameter of the connecting chuck and facing the cabin connecting plate; the special-shaped stress plate has at least two relatively facing and outwardly convex arc-shaped side walls, and each arc-shaped side wall is provided with a stress surface at its connection. The two torque inserts can respectively abut against the two stress surfaces to generate a push, thereby applying torsional stress to the cabin.

[0013] Furthermore, it further includes a multiple linkage testing structure cooperating with the torsional stress applying structure, including: a stress transmission column provided on the connecting chuck and facing the special-shaped stress plate for transmitting the torsional moment; a stress adjusting plate having an inclined surface at a specific angle, fixedly arranged at one end of the stress transmission column close to the special-shaped stress plate; a stress adjusting wheel capable of freely rotating, axially fixedly connected to the edge of the special-shaped stress plate, and its arc surface forms a tangential contact with the inclined surface of the stress adjusting plate.

[0014] Furthermore, the special-shaped stress plate is arranged in central symmetry, the arc-shaped side walls are provided with four sides, and four stress adjusting wheels are provided and are respectively located between every two adjacent arc-shaped side walls.

[0015] The present invention also provides a method for detecting the strength of a composite material cabin using the above detection tooling, including the following steps: S1. Cabin installation: Install and fix the composite material cabin on the detection tooling through the cabin connecting plate, and fix one end on the support working frame through the end fixing device; S2. Initial detection: Apply a predetermined bending moment load at the other end of the cabin through the force application adjusting device, and use the deformation measuring structure to monitor the deformation amount of the loaded end of the cabin in real time to ensure that the deformation amount is controlled within the qualified target range, and at the same time visually inspect the integrity of the inner and outer surfaces of the cabin; S3. Surface-changing detection: When the initial direction detection is qualified, rotate the execution part of the load tooling by 90°, and use the qualified deformation amount value recorded during the previous detection as the displacement control target to apply a bending moment load to the same end of the cabin in the new direction; S4. Multi-direction comprehensive detection: Perform 4 times of 90° rotation detections in sequence according to the method of step S3 to achieve a comprehensive evaluation of the bending moment strength of the cabin in four directions of 0°, 90°, 180°, and 270°.

[0016] Further, the initial detection in step S2 specifically includes: S21. Apply a unidirectional bending moment load to the cabin through a unidirectional stress application structure, and facilitate adjusting the stress magnitude by displaying the stress value in real time; S22. Monitor the deformation amount of the cabin through a deformation measurement structure, and record the deformation amount value when the qualified stress is reached; S23. Visually inspect whether there are defects such as cracking and delamination on the surface of the cabin.

[0017] Further, the surface-changing detection in step S3 adopts a displacement control mode, specifically: taking the qualified deformation amount value recorded in step S2 as the displacement control target, and quickly reaching the same deformation amount by controlling the rotation angle of the force transmission structure, avoiding the iterative process of re-performing force loading - deformation measurement.

[0018] Further, in the multi-direction comprehensive detection, the multi-direction stress test is realized in the following way: Loosen the connection between the second crossbeam frame and the support working frame, and move along the support working frame to drive the torsional stress application structure to disengage from the force transmission structure; Rotate and reverse the connection chuck so that the stress adjustment plate on it corresponds to the stress adjustment wheels in other orientations; Re-move and install the second crossbeam frame to a suitable position and repeat the detection operation.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The detection efficiency is significantly improved: The composite material cabin only needs to be installed and fixed once, and the bending moment load detection in multiple directions can be completed, greatly improving the detection efficiency and reducing the errors and time costs brought by repeated clamping.

[0020] Multi-direction comprehensive detection: Through a multiple linkage test structure, it is possible to comprehensively evaluate the bending moment strength of the cabin in four directions of 0°, 90°, 180°, and 270°, ensuring the comprehensiveness and reliability of the detection.

[0021] Displacement control mode: Adopt the displacement control mode for surface-changing detection, and use the qualified deformation amount value recorded in the previous detection as the control target, which can quickly reach the preset deformation amount and significantly improve the detection efficiency.

[0022] High detection accuracy: The stress value is displayed in real time through a displayable hanging scale, and the deformation amount is accurately monitored through a deformation measurement structure, ensuring the accuracy and reliability of the detection results.

[0023] Strong applicability: The detection tooling can be applied to composite material cabins of different shapes, including special-shaped cylindrical structures and cylindrical structures, with good versatility.

[0024] Rich stress types: It can simultaneously perform unidirectional stress and torsional stress detections, comprehensively evaluate the mechanical properties of the cabin, and meet different detection requirements. Description of the Drawings

[0025] Figure 1 Structural schematic diagram of one kind of composite material cabin body of the present invention; Figure 2 Structural schematic diagram of another kind of composite material cabin body of the present invention; Figure 3 Partial structural schematic diagram of the present invention for detecting the cabin body; Figure 4 Partial structural schematic diagram of the present invention when the unidirectional stress application structure is installed on the support workbench; Figure 5 Partial structural schematic diagram of the present invention when the torsional stress application structure is installed on the support workbench; Figure 6 Structural schematic diagram of the torsional stress application structure of the present invention; Figure 7 is Figure 6 Local enlarged view of part Ⅰ in Figure 8 Structural schematic diagram of the force transmission structure of the present invention; Figure 9 Planar schematic diagram of the present invention where only the multiple linkage test structure generates unidirectional stress on the special-shaped stress-bearing plate; Figure 10 Planar schematic diagram of the present invention where only the torque plug transmits torsional stress to the special-shaped stress-bearing plate; Figure 11 Structural schematic diagram of the airtightness detection structure for the cross-section of the cabin body of the present invention; Figure 12 Structural schematic diagram of the present invention when the installation and fixing device is disassembled; Figure 13 Schematic diagram of the bending moment load detection process; Figure 14 Schematic diagram of the multiple linkage test process.

[0026] Reference numerals: cabin body 01, threaded through-hole 02, support working frame 10, installation and fixing device 20, force application and adjustment device 30, deformation measurement structure 40, sealing performance detection structure 50, cabin body connecting plate 21, quick lock 22, fixing plate 23, unidirectional stress application structure 31, torsional stress application structure 32, force transmission structure 33, multi-linkage test structure 34, universal adjustment bracket 41, dial indicator 42, detection lamp 51, adjustment mounting bracket 52, first through-hole 53, second through-hole 54, communication hole 211, first cross beam frame 311, displayable hanging scale 312, stress adjustment structure 313, connection block 314, second cross beam frame 321, torque wrench 322, torque adjustment structure 323, special-shaped stress-bearing plate 331, unidirectional stress transmission member 332, torsional stress transmission assembly 333, support and stabilizer plate 334, stress transmission column 341, stress adjustment plate 342, stress adjustment wheel 343, hook 3121, threaded hole 3131, operating screw 3132, motor 3231, lead screw 3232, adjustment slider 3233, operating wheel 3234, movable push-rotating member 3235, limiting space 3236, arc-shaped side wall 3311, stress-bearing surface 33111, hanging ring 3321, connection chuck 3331, torque plug-in 3332. Detailed implementation mode

[0027] Embodiment: This embodiment is used to detect the strength characteristics of the composite material cabin body 01 under stress.

[0028] The composite material cabin body 01 is made of glass fiber reinforced plastic (FRP), and metal parts are embedded in local areas to enhance the structural strength. According to the actual use requirements, the specific structural forms of the cabin body 01 mainly include the following several types: One. As Figure 1 shown in the special-shaped cylindrical structure: This structure is a symmetrical cylindrical body with both ends connected, and the overall shape is similar to a rectangle, and the shapes and sizes of the two end faces are different.

[0029] Two. As Figure 2 shown in the cylindrical structure: This structure is also a cylindrical body with both ends connected, but the shapes and sizes of the two end faces are the same, both being circular.

[0030] In order to realize the reliable connection between the cabin body and the detection equipment, regardless of the structural form adopted, a plurality of threaded through-holes 02 are provided on the outer peripheral wall of the end of the cabin body 01 for realizing the reliable connection and fixation with other components of the unmanned aerial vehicle.

[0031] Based on the above structural characteristics of the cabin body, this embodiment provides a strength detection tooling for detecting the above-mentioned composite material cabin body 01 of the unmanned aerial vehicle. This tooling adopts the method of step-by-step loading and multi-directional detection, and the specific detection process is as follows: Initial Detection: When conducting a bending moment load test on the composite material cabin 01, first fix one end of the cabin 01 reliably through a fixture, and then apply a predetermined bending moment load to the other end. The deformation detection device is used to monitor the deformation of the loaded end of the cabin 01 in real time to ensure that the deformation is controlled within the qualified target range. At the same time, visually inspect the integrity of the inner and outer surfaces of the cabin 01 to observe whether there are defects such as cracking and delamination.

[0032] Face-changing Detection: After the initial direction detection is qualified (i.e., the deformation is within the allowable range and there are no surface defects), face-changing detection is carried out. The specific operation is as follows: Rotate the execution part of the load tooling by 90°, and use the qualified deformation value recorded during the previous detection as the displacement control target to apply a bending moment load to the same end of the cabin 01 in the new direction. Since the displacement control mode is adopted, the preset deformation can be quickly reached, significantly improving the detection efficiency. After reaching the target deformation, check the surface integrity of the cabin again to determine whether the strength in this direction is qualified.

[0033] Multi-directional Comprehensive Detection: Perform 4 times of 90° rotation detections in sequence according to the above method to achieve a comprehensive evaluation of the bending moment strength of the cabin 01 in four directions of 0°, 90°, 180°, and 270°.

[0034] Detection Advantages: The advantage of adopting this detection method is that the composite material cabin 01 only needs to be installed and fixed once to complete the bending moment load detection in multiple directions, greatly improving the detection efficiency and reducing the errors and time costs caused by repeated clamping.

[0035] 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 support working frame 10 standing on the ground; an end fixing device 20 installed on the support working frame 10; a force application adjusting device 30 arranged on the support working frame 10; and an independently configured deformation measuring structure 40.

[0036] The cabin connecting plate 21, as the interface component between the tooling and the cabin, has a shape corresponding to the port shape of the cabin 01, with a plurality of screw holes on its circumferential surface and a plurality of through holes 211 on its end face. The screw holes are used to cooperate with the threaded through holes 02 at the end of the cabin 01 to achieve connection and fixation; the through holes 211 are used to achieve end face fixation or connection with the force application adjusting device 30.

[0037] The end fixing device 20 undertakes the function of installing and fixing the cabin. Refer to Figure 3, which is used to fixedly install the cabin 01 on the support working frame 10, includes a quick locking device 22 and a fixing plate 23 connected to the support working frame 10. A plurality of quick locking devices 22 realize the quick connection or quick disassembly of the cabin connecting plate 21 and the fixing plate 23, thereby completing the installation and fixation of the cabin 01 on the support working frame 10. The quick locking device 22 is an optional fastener well-known to those skilled in the art, and the quick locking device 22 can also use ordinary bolts as an alternative solution.

[0038] The force application and adjustment device 30 is the core design of this detection tooling. Refer to Figures 3 - 4 , which is used to apply stress loads to the cabin 01 and realize the function of changing the detection surface, includes a unidirectional stress application structure 31, which is used to apply a preset unidirectional stress to detect whether the deformation characteristics of the cabin 01 meet the requirements; a torsional stress application structure 32, which is used to apply torsional stress to detect the strength characteristics of the cabin 01; a force transmission structure 33, which serves as a transmission carrier for transmitting external stress to the cabin 01, is connected to the cabin connecting plate 21 through the quick locking device 22, and cooperates with the unidirectional stress application structure 31 and the torsional stress application structure 32.

[0039] The unidirectional stress application structure 31 is responsible for applying a controllable unidirectional load. Refer to Figure 4 , including: a first crossbeam frame 311, which serves as the support and installation carrier of this structure and can be detachably installed on the upper end of the support working frame 10; a displayable 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 displayable hanging scale 312 to adjust the stress magnitude.

[0040] In order to achieve precise force control, the lower end of the displayable hanging scale 312 has a hook 3121 that is hung and cooperated 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 threaded holes 3131 of the first crossbeam frame 311 and the connecting block 314. Therefore, by rotating the operating screw 3132, the thread pre-tightening force can be adjusted to achieve stress adjustment until the value displayed by the displayable hanging scale 312 reaches the preset value.

[0041] The torsional stress application structure 32 is specifically used to apply torsional loads. Refer to Figures 5 - 6 , including: a second crossbeam frame 321, which serves as the support and installation carrier of the torsional stress application structure 32 and can be detachably installed on the upper end of the support working frame 10; a torque wrench 322, which is detachably connected to the force transmission structure 33 and can directly display the torsional stress value it applies; a torque adjustment structure 323, which is connected to the lower end of the second crossbeam frame 321 and cooperates with the torque wrench 322 to stably drive the torque wrench to rotate slightly to ensure the reliability of the detection.

[0042] Among them, the torque adjustment structure 323 adopts a lead screw structure, including a motor 3231, a lead screw 3232, an adjustment slider 3233, and an operation wheel 3234. The motor 3231 and the operation wheel 3234 are respectively connected to the upper end and the lower end of the lead screw 3232. The adjustment slider 3233 is threadedly connected to the lead screw 3232. The adjustment slider 3233 is also provided with a movable pushing and rotating member 3235 having a limiting space 3236. The torque wrench 322 passes through the limiting space 3236. Through this structural design, the lead screw 3232 can be driven to rotate by the motor 3231 or the operation wheel 3234, thereby driving the adjustment slider 3233 and the movable pushing and rotating member 3235 connected thereto to move up and down. While the movable pushing and rotating member 3235 drives the torque wrench 322 to move up and down, it also makes it move left and right along the limiting space 3236, thereby realizing the rotation of the torque wrench 322 and applying a torsional stress to the cabin body 01.

[0043] The design advantage of the torsional stress application structure 32 is that the torque change can be kept gentle and stable, ensuring the reliability of the detection. Moreover, for a single torsional stress test, the operation wheel 3234 can be manually controlled, which saves time, effort and resources. For multiple repeated torsional stress tests, the motor 3231 can be enabled for repeated tests, which improves the test efficiency and also ensures the test effect.

[0044] The force transmission structure 33 is a key link for load transmission. 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 locking device, and its central axis is collinear with the central axis of the cabin body 01; a unidirectional stress transmission member 332, which is connected and matched with the unidirectional stress application structure 31; a torsional stress transmission assembly 333, which is connected and matched with the torsional stress application structure 32.

[0045] Refer to Figure 4 , the unidirectional stress transmission member 332 adopts a hanging ring 3321, which is arranged at the center of the special-shaped force-bearing plate 331, for example, connected to the central axis of the special-shaped force-bearing plate 331, and is used to realize the hanging cooperation with the hook 3121 of the visible hanging scale 312, so as to realize the stress transmission from the unidirectional stress application structure 31 to the cabin body 01.

[0046] The torsional stress transmission assembly 333 undertakes the function of transmitting torsional loads. Refer to Figure 6 、 Figure 8, cooperating with the special-shaped stress-bearing plate 331, includes: a connecting chuck 3331 detachably inserted into the torque wrench 322; two torque inserts 3332 formed at both ends of the diameter of the connecting chuck 3331 and facing the cabin connecting plate 21. The special-shaped stress-bearing plate 331 has at least two relatively facing and outwardly convex arc-shaped side walls 3311, and each arc-shaped side wall 3311 is provided with a stress-bearing surface 33111 at its head and tail. The two torque inserts 3332 can respectively abut against the two stress-bearing surfaces 33111 to generate a push force, thereby applying a torsional stress to the cabin 01.

[0047] The working process of torsional stress transmission is as follows: Rotate the torque wrench 322, so that it drives the two torque inserts 3332 to rotate through the connecting chuck 3331. The torque inserts 3332 rotate along the arc-shaped side wall 3311, pushing the stress-bearing surface 33111 at the junction of the arc-shaped side wall 3311, so that the extrusion stress between the torque insert 3332 and the stress-bearing surface 33111 gradually increases. The gradually increasing thrust force formed by the extrusion stress drives the special-shaped stress-bearing plate 331 to have a rotation tendency, thereby generating a bending moment and transmitting it to the cabin 01.

[0048] To ensure stable and reliable torque transmission, referring to Figure 5 , a support and stabilizer plate 334 connected to the second crossbeam frame 321 is provided. It is provided with a mounting hole that closely rotates in cooperation with the central axis of the connecting chuck 3331 to play a role in supporting the connecting chuck 3331 and ensuring the stable rotation of the connecting chuck 3331.

[0049] The multiple linkage test structure 34, referring to Figures 6 - 8 , cooperating with the torsional stress application structure 32, includes: a stress transmission column 341: arranged on the connecting chuck 3331 and facing the special-shaped stress-bearing plate 331, used to transmit a unidirectional torque; a stress adjustment plate 342: having a bevel surface at a specific angle, fixedly arranged at one end of the stress transmission column 341 close to the special-shaped stress-bearing plate 331; a stress adjustment wheel 343: rotatable freely, axially fixedly connected to the edge of the special-shaped stress-bearing plate 331, and its arc surface forms a tangential contact with the bevel surface of the stress adjustment plate 342.

[0050] The core technical principle of the multiple linkage test structure 34 is: through the principles of geometric constraint and contact mechanics, the rotational torque of the connecting chuck 3331 is converted into a radial unidirectional pressure on the special-shaped stress-bearing plate 331: 1. Initial contact state: The arc surface of the stress adjustment wheel 343 forms a tangential contact with the bevel surface of the stress adjustment plate 342 at a specific point, and the normal force at the contact point is perpendicular to the tangential direction.

[0051] 2. Decomposition and transmission of force: When the connecting chuck 3331 generates a torsional moment, the moment is transmitted to the stress adjustment plate 342 through the stress transmission column 341. Due to the geometric constraint of the inclined plane, the force acting on the contact point can be decomposed into: a. The tangential component force along the inclined plane (driving the wheel to roll); b. The normal component force perpendicular to the inclined plane (generating a squeezing effect).

[0052] 3. Motion conversion process: Under the constraint of the inclined plane, the stress adjustment wheel 343 rolls from the low end to the high end. During the rolling process: The vertical displacement of the wheel center 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 special-shaped force-bearing plate 331, the plate generates a corresponding radial displacement. This displacement is converted into a unidirectional compressive stress on the cabin body 01 under the constraint of the plate.

[0053] This structure has a unique two-stage working mode: The first stage ( 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 is separated from the stress adjustment wheel 343 (gap δ > 0). In this stage, only through the contact between the torque plug 3332 and the force-bearing surface 33111, a pure torsional moment is applied to the special-shaped force-bearing plate 331.

[0054] The second stage ( Figure 10 as shown): The torque plug 3332 rotates in the opposite direction relative to the first stage, separating the torque plug 3332 from the force-bearing surface 33111. The lower end of the inclined plane of the stress adjustment plate 342 makes a tangential contact with the stress adjustment wheel 343. When continuing to rotate, the stress adjustment wheel 343 rolls upward along the inclined plane, generating a radial extrusion force: F = P·cos(α) (where P is the total acting force at the contact point and α is the inclined plane angle). This radial force is transmitted to the edge of the cabin body 01 through the special-shaped force-bearing plate 331, forming a unidirectional compressive stress.

[0055] Referring to Figures 11 - 14 , as shown, this multiple-linkage test structure has the following technical advantages: Stress mode switching: Through a clever geometric design, a smooth conversion from torsional stress to unidirectional compressive stress is achieved, avoiding stress mutation. Force amplification effect: Using the wedge principle of the inclined plane, a smaller torsional moment can be converted into a larger radial pressure, 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 full-range strength detection. Precise displacement control: By controlling the torsional 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 the real-time monitoring of the deformation measurement structure 40, rapid detection based on displacement control can be achieved.

[0056] The design of this multi-linkage test structure fully considers the technological requirements of panel change detection: Implementation of displacement control mode: During the initial direction detection, the deformation measurement structure 40 records the deformation δa of the cabin body when the qualified stress is reached. During the panel change detection, this deformation δa is used as the displacement control target. By precisely controlling the rolling distance of the stress adjustment wheel 343 on the inclined plane, the same deformation can be quickly achieved. The displacement control relationship is: δ = f(θ, α, r) = r·θ·sin(α)·K (where K is the system transfer coefficient).

[0057] Fast positioning mechanism: Using the known value of the qualified deformation, the target torsion angle θ required can be directly calculated, avoiding the iterative process of reloading force - deformation measurement, significantly improving the detection efficiency, and reducing the test time.

[0058] Guarantee of multi-direction consistency: Through a unified displacement control algorithm, it ensures that the detection conditions in all directions (0°, 90°, 180°, 270°) are consistent, eliminates the systematic errors caused by repeated clamping and recalibration, and guarantees the comparability of multi-direction detection results.

[0059] To ensure the system performance, the key design parameters are required as follows: Inclined plane angle α: It should be determined according to the required force amplification factor, rolling stability, and displacement control accuracy requirements, generally taking 15° - 30°; Stress adjustment wheel radius r: It should match the inclined plane length and the expected deformation range to ensure that the effective working stroke covers the qualified deformation interval; System transfer coefficient K: It needs to be determined through calibration tests to establish an accurate correspondence between the torsion angle and the cabin body deformation; Contact surface treatment: It should have an appropriate surface roughness (Ra 1.6 - 3.2μm) to ensure rolling rather than sliding and ensure the accuracy of displacement transfer; Material strength: It should meet the safety factor requirements (≥2.5) under the maximum design load, and at the same time consider the fatigue strength to meet the requirements of multiple detections.

[0060] Preferably, referring to Figures 8 - 10 , the special-shaped force-bearing plate 331 is arranged in central symmetry, and there are multiple stress adjustment wheels 343 on it. The arc-shaped side wall 3311 has multiple faces and is pairwise opposite; In this embodiment, the arc-shaped side wall 3311 has four faces, and there are four stress adjustment wheels 343 which are respectively located between every two adjacent arc-shaped side walls 3311. Correspondingly, the torque wrench 322 uses a square head drive at the four corners.

[0061] Based on the above multi-linkage structure design, without adjusting the attitude of the cabin body 01, it is possible to realize the multi-directional edge unidirectional stress test of the multi-linkage test structure 34, which not only further enriches the diversity of strength detection but also ensures the detection efficiency. Specifically, as Figure 5As shown in the figure, loosen the bolts fixing the second crossbeam frame 321 to the support working frame 10 and roll it along the support working frame 10 to drive the torsional stress application structure 32 away from the force transmission structure 33. Refer to Figure 6 , then rotate the connection chuck 3331 to reverse its direction so that the stress adjustment plate 342 on it corresponds to the stress adjustment wheels 343 in other directions. Then, move and reinstall the second crossbeam frame 321 to a suitable position and repeat the above detection operations.

[0062] To accurately monitor the deformation response of the cabin, refer to Figure 4 , the deformation measurement structure 40 is used to detect the amount of deformation on the surface of the cabin 01. Multiple groups can be set (only one group is shown in the figure). Each group includes a universal adjustment bracket 41 and a dial indicator 42. The dial indicator 42 is closely attached to the surface of the cabin 01, and its detection accuracy can be accurate to 0.001 mm. The dial indicator 42 is detachably connected to the universal adjustment bracket 41. The universal adjustment bracket 41 uses an existing technology product and can achieve multi-directional adjustment.

[0063] After completing the mechanical property detection, to comprehensively evaluate the quality of the cabin, refer to Figure 6 , Figure 11 , after applying torsional stress or unidirectional stress to the cabin 01 by using the above torsional stress application structure 32, force transmission structure 33, and multiple linkage test structure 34, in order to facilitate observing whether there are obvious cracks in the cabin 01, this detection tooling is also equipped with a sealing detection structure 50. It utilizes the characteristic that light can penetrate the fiberglass cabin 01. By setting a light source inside the middle of the cabin 01 and observing the brightness to judge whether there are cracks. If there are doubts about the bright part, a special device can be used to further detect the sealing of this place.

[0064] As Figure 11 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, passes through the first through hole 53 of the fixed plate 23 and the second through hole 54 of the cabin connection plate 21, and extends the detection lamp 51 to the central position inside the cabin 01.

Claims

1. A strength detection tooling for a composite material cabin of an unmanned aerial vehicle, characterized in that, Comprising: A cabin connecting plate (21), detachably connected to both ends of a composite cabin (01), the shape of the cabin connecting plate (21) corresponding to the shape of the port of the cabin (01), and a plurality of communication holes (211) provided on the end face; A support working frame (10), standing on the ground; An end fixing device (20), installed on the support working frame (10) for fixedly installing the cabin (01) on the support working frame (10); A force application and adjustment device (30), arranged on the support working frame (10) for applying a stress load to the cabin (01), including: a unidirectional stress application structure (31) for applying a preset unidirectional stress; a torsional stress application structure (32) for applying a torsional stress; a force transmission structure (33) serving as a transmission carrier for transmitting external stress to the cabin (01); A deformation measurement structure (40) for detecting the amount of deformation on the surface of the cabin (01); Wherein, the force transmission structure (33) includes: a special-shaped force-bearing plate (331) having a central axis or hole, detachably connected to the cabin connecting plate (21), and the axis of its central axis or hole being collinear with the central axis of the cabin (01); a unidirectional stress transmission member (332), connected and cooperating with the unidirectional stress application structure (31); a torsional stress transmission assembly (333), connected and cooperating with the torsional stress application structure (32); By the selective connection and cooperation of the force transmission structure (33) with the unidirectional stress application structure (31) and the torsional stress application structure (32), the detection of different types of stress loads on the composite cabin (01) is realized.

2. The strength detection tooling for the composite material cabin of the unmanned aerial vehicle according to claim 1, wherein, The unidirectional stress application structure (31) includes: A first crossbeam frame (311), detachably installed at the upper end of the support working frame (10); A displayable hanging scale (312), connected to the lower end of the first crossbeam frame (311) through a connecting block (314); A stress adjustment structure (313), cooperating with the displayable hanging scale (312) for adjusting the stress magnitude.

3. The strength detection tooling for the composite material cabin of the unmanned aerial vehicle according to claim 1, wherein The torsional stress application structure (32) includes: A second crossbeam frame (321), detachably installed at the upper end of the support working frame (10); A torque wrench (322), detachably connected to the force transmission structure (33) and capable of directly displaying the value of the torsional stress applied by it; A torque adjustment structure (323), connected to the lower end of the second crossbeam frame (321) and cooperating with the torque wrench (322) for stably driving the torque wrench to rotate in a small amplitude.

4. The strength detection tooling for the composite material cabin of the unmanned aerial vehicle according to claim 1, wherein, The torsional stress transmission assembly (333) includes: A connecting chuck (3331), detachably inserted into the torque wrench (322); Two torque inserts (3332), formed at both ends of the diameter of the connecting chuck (3331) and arranged towards the cabin connecting plate (21); The special-shaped force-bearing plate (331) has at least two opposite and outwardly convex arc-shaped side walls (3311), and a force-bearing surface (33111) is provided at the junction of each arc-shaped side wall (3311). The two torque inserts (3332) can respectively abut against the two force-bearing surfaces (33111) to generate a push so as to apply a torsional stress to the cabin (01).

5. The strength detection tooling for the composite material cabin of the unmanned aerial vehicle according to claim 4, characterized in that, It further includes a multiple linkage test structure (34), which cooperates with the torsional stress application structure (32) and includes: A stress transmission column (341) is arranged on the connecting chuck (3331) and faces the special-shaped stress-bearing plate (331) for transmitting the torsional moment; A stress adjustment plate (342) with an inclined surface at a specific angle is fixedly arranged at one end of the stress transmission column (341) close to the special-shaped stress-bearing plate (331); A stress adjustment wheel (343) can rotate freely and is axially fixedly connected to the edge of the special-shaped stress-bearing plate (331), and its arc surface is in tangential contact with the inclined surface of the stress adjustment plate (342).

6. The strength detection tooling for the composite material cabin of the unmanned aerial vehicle according to claim 5, wherein, The special-shaped stress-bearing plate (331) is arranged in central symmetry, and four sides of the arc-shaped side walls (3311) are symmetrically arranged in pairs around the center of the special-shaped stress-bearing plate (331). Four stress adjustment wheels (343) are arranged and are respectively located between every two adjacent arc-shaped side walls (3311).

7. A detection method using the detection tool for the strength of the composite material cabin of the unmanned aerial vehicle according to any one of claims 1-6, characterized in that, It includes the following steps: S1. Cabin installation: Install and fix the composite cabin (01) on the test fixture through the cabin connecting plate (21), and fix one end on the support workbench (10) through the end fixing device (20); S2. Initial detection: Apply a predetermined bending moment load to the other end of the cabin (01) through the force application adjustment device (30), and use the deformation measurement structure (40) to monitor the deformation amount of the loaded end of the cabin (01) in real time to ensure that the deformation amount is controlled within the qualified target range, and at the same time visually inspect the integrity of the inner and outer surfaces of the cabin (01); S3. Surface change detection: When the initial direction detection is qualified, rotate the execution part of the load tooling by 90°, and use the qualified deformation amount value recorded during the previous detection as the displacement control target to apply a bending moment load to the same end of the cabin (01) in the new direction; S4. Comprehensive multi-directional detection: Perform 4 times of 90° rotation detections in sequence according to the method of step S3 to achieve a comprehensive evaluation of the bending moment strength of the cabin (01) in four directions of 0°, 90°, 180°, and 270°; 8. The detection method according to claim 7, wherein The initial detection in step S2 specifically includes: S21. Apply a unidirectional bending moment load to the cabin (01) through the unidirectional stress application structure (31), and display the stress value in real time to facilitate adjusting the stress magnitude; S22. Monitor the deformation amount of the cabin (01) through the deformation measurement structure (40) and record the deformation amount value when the qualified stress is reached; S23. Visually inspect whether there are cracking and delamination defects on the surface of the cabin (01).

9. The detection method according to claim 7, wherein The surface change detection in step S3 adopts a displacement control mode, specifically: Use the qualified deformation amount value recorded in step S2 as the displacement control target, and quickly reach the same deformation amount by controlling the rotation angle of the force transmission structure (33) to avoid repeating the iterative process of force loading - deformation measurement.

10. The detection method according to claim 7, characterized in that, In the comprehensive multi-directional detection, multi-directional stress tests are realized through the following methods: Loosen the connection between the torsional stress application structure (32) and the support workbench (10), and move along the support workbench (10) to drive the torsional stress application structure (32) to disengage from the force transmission structure (33); After the special-shaped stress plate (331) is rotated and reversed, reinstall the second crossbeam frame (321) by moving it to a suitable position, and repeat the detection operation.

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