Rotor hub system static strength loading mechanism

Abstract

The application relates to a rotor hub system static strength loading mechanism. A test piece clamping tool is fixed on a test bench base, the test piece clamping tool is provided with an inclined fitting surface matched with the installation inclination angle of a rotor hub support arm, and the test piece clamping tool is used for embracing and locking a rotor hub test piece; one end of a load transmission rod is hinged to a straight clamp plate of the rotor hub test piece; a multi-directional load adapter is connected to the other end of the load transmission rod, the multi-directional load adapter is respectively connected to a flapping driving element, a pendulum driving element and a centrifugal driving element, and is used for synchronously transmitting flapping load, pendulum load and centrifugal load to the load transmission rod; one end of a variable-pitch load loading assembly is connected to the rotor hub test piece, and the other end of the variable-pitch load loading assembly is hung with a counterweight bearing element, and is used for applying a variable-pitch pull rod load to the rotor hub test piece; one-time clamping can realize synchronous staged composite loading of four types of loads, i.e. flapping, pendulum, centrifugal and variable-pitch pull rod, the original inclination angle of the rotor hub support arm can be accurately matched, and the test load fidelity and test efficiency are improved.

Description

Technical Field

[0001] This application relates to the field of helicopter propeller testing fixtures, and in particular to a static strength loading mechanism for a rotor hub system. Background Technology

[0002] During the development phase of a certain type of propeller rotor hub, it is necessary to conduct static strength tests on the complete rotor hub support arm. The tests will verify the static strength performance of the rotor hub structure and provide experimental data support for the evaluation of the rotor hub structure and the calibration of its service life.

[0003] This test requires a specialized loading fixture. This fixture must simulate the actual blade installation state to clamp the rotor hub and simultaneously apply four types of loads during rotor operation: flapping load, oscillation load, centrifugal load, and pitch linkage load. Existing conventional static strength testing fixtures can only apply a single component and a single load independently, which has the following limitations: It is impossible to apply all the working loads of the rotor hub simultaneously and in combination. Multiple separate tests are required, which results in long test cycles, repeated clamping errors introduced by multiple clamping, and large deviations between test data and actual flight conditions. The rotor hub star-shaped support arm has a fixed tilt angle with the horizontal plane. The existing tooling does not have a matching tilt angle clamping structure, so the centrifugal load cannot be applied along the support arm axis. The loading process generates additional lateral force and additional bending moment, resulting in poor load fidelity. Summary of the Invention

[0004] This application provides a static strength loading mechanism for a rotor hub system, which solves the problems of multiple loads not being able to be applied synchronously and the poor tilt angle matching accuracy in the existing rotor hub static strength test fixtures.

[0005] On the one hand, this application provides a static strength loading mechanism for a rotor hub system, comprising: Test bench base; The specimen clamping fixture is fixed on the test bench base. The specimen clamping fixture has an inclined contact surface that matches the installation tilt angle of the rotor hub support arm. The specimen clamping fixture is used to hold and lock the rotor hub test specimen. The load transmission rod is hinged at one end to the straight clamping plate of the rotor hub test piece; The multi-directional load transfer fixture is connected to the other end of the load transmission rod. The multi-directional load transfer fixture is connected to the swing drive component, the swing drive component, and the centrifugal drive component respectively, and is used to synchronously transmit the swing load, the swing load, and the centrifugal load to the load transmission rod. The variable pitch load loading assembly is connected to the rotor hub test piece at one end and a counterweight bearing is suspended at the other end, which is used to apply variable pitch tie rod load to the rotor hub test piece. The waving drive, the swing drive, the centrifugal drive, and the counterweight bearing constitute four independent loading branches. The four loading branches can synchronously and gradedly output composite loads, and all loads act on the rotor hub test specimen along the force axis of the rotor hub support arm.

[0006] In one possible design, the specimen clamping fixture includes: The mounting base is U-shaped. The upper pressure support is set on the inner wall of one side of the fixed seat. The upper pressure support and the inner wall of the other side of the fixed seat form an inclined contact surface with the same inclination angle. The rotor hub test piece is clamped and confined between the two inclined contact surfaces.

[0007] In one possible design, the fixed base is connected to the test bench base by fastening bolts; the fixed base, rotor hub test piece, and upper pressure support are locked together by clamping bolts; the upper pressure support and the fixed base are also connected by reinforcing bolts.

[0008] In one possible design, strain acquisition elements are arranged on the load transmission rod, and the strain acquisition elements are electrically connected to a static strain testing device.

[0009] In one possible design, the multi-directional load transfer fixture includes a main force transmission rod, a oscillation adapter, a swinging connecting fork, a first-stage centrifugal adapter, and a second-stage centrifugal adapter. The main force transmission rod passes through a through-hole in the end of the centrifugal loading rod away from the rotor hub test piece. The oscillation adapter is fitted onto the outside of the main force transmission rod and connected to the oscillation drive. The outer end of the main force transmission rod is connected to the swinging drive via the swinging connecting fork. The first-stage centrifugal adapter is fitted onto the main force transmission rod and connected to the second-stage centrifugal adapter via a threaded rod. The end of the second-stage centrifugal adapter is connected to the centrifugal drive via a traction cable.

[0010] In one possible design, the variable pitch load loading assembly includes a flexible traction element and a fixed pulley. One end of the flexible traction element is connected to the variable pitch rocker arm of the rotor hub test specimen. After the flexible traction element passes around the fixed pulley on the test bench base, a counterweight bearing is suspended to apply a variable pitch tie rod load to the rotor hub test specimen.

[0011] In one possible design, a fixed base plate and a clamping support plate are also included. The fixed base plate is fixed to the test bench base, and the clamping support plate is fitted and wrapped around both sides of the load transmission rod to keep the load transmission rod at the same installation angle as the rotor hub arm.

[0012] In one possible design, a temporary support is also included, which is located below the hinge joint between the load transmission rod and the straight clamp of the rotor hub test piece, and is used to support the load transmission rod during the assembly stage.

[0013] In one possible design, an environmental temperature control chamber is also included. The environmental temperature control chamber is a sealable cavity that covers the rotor hub test specimen to provide a controllable temperature test environment. It also includes a temperature acquisition component, which includes a temperature sensor and a multi-channel temperature recorder. The temperature sensor is attached to the test area of ​​the rotor hub test piece and electrically connected to the corresponding temperature recorder.

[0014] In one possible design, the waving drive, the swing drive, and the centrifugal drive each integrate independent load sensing elements, and all load sensing elements are uniformly connected to the load data acquisition terminal.

[0015] The beneficial effects of this application are as follows: The static strength loading mechanism of the rotor hub system in this application can simultaneously apply flapping, oscillation, centrifugal, and variable pitch rod composite loads by setting four independent loading branches. The static strength test of the rotor hub under all working conditions can be completed in a single clamping, without the need for multiple disassembly and assembly of the test piece, which greatly shortens the test cycle and eliminates the test error caused by multiple clamping. The specimen clamping fixture is equipped with double inclined contact surfaces, which precisely match the original installation tilt angle of the rotor hub arm, ensuring that the centrifugal load is applied axially along the arm axis, without any extra lateral force or additional bending moment, and the test load is highly consistent with the actual flight conditions. The multi-directional load transfer fixture adopts a two-stage centrifugal transfer component, which achieves coaxial nesting of three types of loading structures: swinging, oscillating, and centrifugal, through a stepped segmented structure, completely solving the problem of spatial interference at multi-load joints; the two-stage transfer component has an adjustable threaded connection, which can compensate for tooling machining errors and high-temperature thermal deformation, while dispersing the ultra-large centrifugal tension, improving the structural strength and service life of the tooling; the modular structure makes it easy to replace the traction cable and drive components individually, and the debugging and disassembly are convenient; The matching fixed base plate and clamping support plate form an angle limiting structure, which rigidly constrains the attitude of the load transmission rod throughout the test, avoids the deflection of the rod during the loading process, and continuously ensures the stability of the load application direction. An independent temporary support is set up to support the weight of the load transmission rod during the assembly stage, protect the rotor hub specimen and the hinge pin, and can be detached from the rod during formal loading without introducing additional constraint stress. The integrated enclosed environment temperature control chamber and temperature acquisition components enable high-temperature environment simulation and simultaneous acquisition of specimen temperature data. It can complete static strength tests under multiple environments, including normal temperature and high temperature, and covers a wider range of working conditions. The load transmission rod is equipped with strain acquisition elements, and each drive component is equipped with an independent load sensing element. Stress, load, and temperature data are collected synchronously from multiple dimensions, resulting in complete and highly accurate test data. Attached Figure Description

[0016] Figure 1This is a front view of the static strength loading mechanism of the rotor hub system provided in an embodiment of this application; Figure 2 A top view of the static strength loading mechanism of the rotor hub system provided in the embodiments of this application; Figure 3 This is a schematic diagram of the overall structure of the static strength loading mechanism of the rotor hub system provided in the embodiments of this application.

[0017] Figure label: 1. Test bench base; 21. Fixed seat; 22. Upper pressure support; 31. Star-shaped component body; 32. Straight clamp plate; 33. Variable pitch rocker arm; 4. Load transmission rod; 51. Main transmission rod; 52. Swinging vibration adapter; 53. Swinging connecting fork lug; 54. First-stage centrifugal adapter; 55. Second-stage centrifugal adapter; 56. Threaded rod; 57. Swinging drive component; 58. Swinging vibration drive component; 59. Traction cable; 61. Flexible traction component; 62. Fixed pulley; 63. Counterweight bearing component; 71. Fixed base plate; 72. Clamping support plate; 8. Temporary support component; 9. Environmental temperature control chamber. Detailed Implementation

[0018] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The following is combined with Figures 1-3 This describes the static strength loading mechanism for the rotor hub system provided in the embodiments of this application.

[0020] The static strength loading mechanism for the rotor hub system provided in this embodiment includes a test bench base 1, a specimen clamping fixture, a load transmission rod 4, a multi-directional load transfer fixture, and a variable-pitch load loading assembly. The specimen clamping fixture is fixed on the test bench base 1 and has an inclined contact surface that matches the mounting angle of the rotor hub support arm. The specimen clamping fixture is used to hold and lock the rotor hub test specimen. The rotor hub test specimen includes a star-shaped body 31, a straight clamping plate 32, and a variable-pitch rocker arm 33. One end of the load transmission rod 4 is hinged to the straight clamping plate 32 of the rotor hub test piece, and the other end is connected to the multi-directional load transfer fixture. The other end of the multi-directional load transfer fixture is respectively connected to the flapping drive component 57, the oscillation drive component 58, and the centrifugal drive component, which are used to synchronously transmit flapping load, oscillation load, and centrifugal load to the load transmission rod 4. One end of the variable pitch load loading component is connected to the variable pitch rocker arm 33, and the other end is suspended by the counterweight bearing component 63, which is used to apply variable pitch tie rod load to the rotor hub test piece. The flapping drive component 57, the oscillation drive component 58, the centrifugal drive component, and the counterweight bearing component 63 constitute four independent loading branches. The four loading branches can synchronously and gradedly output composite loads, and all loads act on the rotor hub test piece along the force axis of the rotor hub support arm.

[0021] Utilizing the technical solution provided in the above embodiments, a four-way synchronous loading branch is integrated, with the load transmission rod 4 uniformly bearing all loads. A single clamping operation can simultaneously apply four types of composite loads: flapping, oscillation, centrifugal, and pitch-variable tie rod loads, replicating the real-world composite stress state of the rotor hub during flight. This eliminates the need for multiple specimen disassembly and assembly, significantly shortening the test cycle and avoiding repetitive testing errors introduced by multiple clamping operations. The four-way load is applied synchronously and in stages, with the load application method consistent with the actual rotor operation stress law. This allows for a complete assessment of the static strength of all stressed components of the rotor hub's entire support arm in a single operation, providing superior test coverage compared to traditional single-load fixtures. The specimen clamping fixture features a dedicated inclined contact surface that matches the original installation angle of the rotor hub support arm, ensuring that the centrifugal load is output purely axially along the support arm's force axis, eliminating lateral components and additional bending moments, and significantly improving the fidelity of the test load.

[0022] In some embodiments provided in this application, the specimen clamping fixture includes a fixed base 21 and an upper pressure support 22, with the fixed base 21 being U-shaped. The upper pressure support 22 is disposed on one inner wall of the fixed base 21, and both the upper pressure support 22 and the other inner wall of the fixed base 21 form inclined contact surfaces with the same inclination angle. The star-shaped component of the rotor hub test specimen is clamped and confined between the two inclined contact surfaces. Specifically, since there is a 4.5° angle between the support arm of the star-shaped component body 31 of the rotor hub test specimen and the vertical plane, and the centrifugal loading is along the axis of the support arm, in order to simulate the installation state, the fixed surface of the upper pressure support 22 and the other inner wall of the fixed base 21 are designed as 4.5° inclined surfaces. The upper and lower inclined surfaces are simultaneously confined, completely replicating the tilted posture of the rotor hub installation. The forces on both sides are balanced, ensuring that the centrifugal force is applied to both sides of the star-shaped component simultaneously when the centrifugal force is applied, avoiding local stress distortion of the specimen caused by unilateral clamping, and making the test boundary conditions more consistent with the actual installation conditions. Furthermore, the split clamping structure allows for direct hoisting and removal of rotor hub specimens from above without the need for complete disassembly of the base fixture. This makes specimen assembly and disassembly convenient and suitable for hoisting large-size, heavy-duty rotor hub specimens.

[0023] In some embodiments provided in this application, the fixed seat 21 is connected to the test bench base 1 by fastening bolts. The fixed seat 21, the rotor hub test piece, and the upper pressure support 22 are locked together by clamping bolts. The upper pressure support 22 is also connected to the fixed seat 21 by reinforcing bolts. The fixed seat 21, the rotor hub test piece, and the upper pressure support 22 are locked together by a shared clamping bolt, with no gaps between the three mating surfaces. During the loading process, there will be no interlayer separation or slight displacement, ensuring a constant tilt angle. The additional reinforcing bolts connecting the upper pressure support 22 and the fixed seat 21 form a double locking structure, which can cope with the huge overturning moment under ultra-large centrifugal tension and composite load. The overall rigidity of the tooling is stronger and it is not easy to deform or loosen. The graded bolt fastening structure allows for orderly assembly and disassembly. The bolt force is distributed in layers, avoiding overload shear damage to a single bolt, extending the service life of the tooling, and making it suitable for long-term batch static strength testing.

[0024] The load transmission rod 4 is also equipped with strain acquisition elements, which are electrically connected to a static strain testing device. These strain acquisition elements are directly mounted on the load transmission rod 4 body, enabling real-time acquisition of the overall composite stress of the rod and providing direct feedback on the total stress level after the superposition of four types of loads. This achieves synchronous data acquisition of load and stress; no additional external force measuring fixtures are required, as load verification can be completed based on the rod's own strain, simplifying the layout of external measurement and control equipment and reducing the cost of supporting testing equipment. Furthermore, the strain testing device can be zeroed during the assembly no-load stage, eliminating measurement baseline deviations caused by the weight of the load transmission rod 4, resulting in higher accuracy of stress acquisition data.

[0025] In some embodiments provided in this application, the multi-directional load transfer fixture includes a main force transmission rod 51, a oscillation adapter 52, a swinging connecting fork 53, a first-stage centrifugal adapter 54, and a second-stage centrifugal adapter 55. The main force transmission rod 51 passes through a through-hole in the end of the centrifugal loading rod away from the rotor hub test piece. The oscillation adapter 52 is sleeved on the outside of the main force transmission rod 51 and connected to the oscillation drive 58. The outer end of the main force transmission rod 51 is connected to the swinging drive 57 through the swinging connecting fork 53. The first-stage centrifugal adapter 54 is sleeved on the main force transmission rod 51 and is connected end-to-end with the second-stage centrifugal adapter 55. The end of the second-stage centrifugal adapter 55 is connected to the centrifugal drive through a traction cable 59. By integrating the main force transmission rod 51, the oscillating adapter 52, the swinging connecting fork lug 53, the first-stage centrifugal adapter 54, and the second-stage centrifugal adapter 55, the three-dimensional loads are concentrated at the end of the same rod, completely solving the spatial interference problem of the joints for swinging, oscillating, and centrifugal loading. Furthermore, the first-stage and second-stage centrifugal adapters 54 and 55 transmit force in segments, distributing the ultra-large centrifugal tension across segments, reducing the compressive and shear stress on individual adapters, preventing cracking and deformation at the adapter holes, and increasing the tooling's load-bearing capacity. The two-stage adapters are connected by a threaded rod 56, allowing for fine-tuning of the overall assembly length, compensating for tooling machining errors, and offsetting the thermal expansion and contraction of metal under heating conditions, preventing additional preload and load drift during high-temperature loading. Only the second-stage centrifugal adapter 55 needs to be replaced to adapt to different specifications of centrifugal drive components and traction cables, without disassembling the entire swinging and oscillating adapter structure, making debugging, maintenance, and parts replacement more convenient.

[0026] In some embodiments provided in this application, the variable-pitch load loading assembly includes a flexible traction member 61 and a fixed pulley 62. One end of the flexible traction member 61 is connected to the variable-pitch rocker arm 33 of the rotor hub test piece. After the flexible traction member 61 passes around the fixed pulley 62 on the test bench base 1, a counterweight bearing member 63 is suspended to apply a variable-pitch tie rod load to the rotor hub test piece. The counterweight load output is stable without hydraulic fluctuations, accurately simulating the continuous static tension of the variable-pitch tie rod, without load errors caused by hydraulic cylinder drift. The fixed pulley 62 changes the direction of force transmission, and the counterweight is completely suspended, applying only a pure downward force to the variable-pitch rocker arm 33, without introducing additional lateral constraints to the rotor hub, and without interfering with the force transmission of the other three loads. The variable-pitch tie rod load can be steplessly adjusted simply by adding or removing counterweights. The staged loading operation is simple, requires no adjustment of the hydraulic control system, and the load stability is not affected by the hydraulic medium under high and low temperature environments.

[0027] In some embodiments provided in this application, a fixed base plate 71 and a clamping support plate 72 are also included. The fixed base plate 71 is fixedly mounted on the test bench base 1, and the clamping support plate 72 is fitted and covered on both sides of the load transmission rod 4 to keep the load transmission rod 4 at the same installation angle as the rotor hub support arm. The fixed base plate 71 serves as a rigid reference seat, and the clamping support plate 72 covers and fits on both sides of the load transmission rod 4, rigidly constraining the rod's posture throughout the entire process, offsetting the downward deflection tendency caused by centrifugal load and the rod's own weight, and stably maintaining the matching tilt angle of the support arm throughout the test. The support plate covers the rod on both sides, with a large contact area and small local compressive stress, preventing indentations and local plastic deformation on the surface of the load transmission rod 4, thus protecting the accuracy of the force transmission tooling. The base plate can be finely adjusted on the test bench base 1 to adapt to load transmission rods 4 of different lengths and specifications, making the tooling more versatile.

[0028] In some embodiments provided in this application, a temporary support 8 is also included. The temporary support 8 is arranged below the hinge node between the load transmission rod 4 and the rotor hub test piece straight clamp 32, and is used to support the load transmission rod 4 during the assembly stage. During the assembly stage, the temporary support 8 supports the weight of the load transmission rod 4, avoiding the blade pin and rotor hub straight clamp 32 from bearing the bending moment of the rod's own weight for a long time, protecting the expensive rotor hub test piece and hinge pin, and preventing deformation and damage to the test piece during the assembly stage. When assembling the adapter tooling and traction cable, the temporary support 8 lifts the rod, allowing a single person to complete the alignment and assembly of multiple sets of adapter parts, reducing the difficulty of assembly operations. During the formal full-load test, it can be lowered to detach from the rod without introducing additional support constraints and additional stress, ensuring that the test load is applied independently by only four loading branches, and the test data is free from interference. At the same time, it serves as a failure protection redundancy to prevent the rod from falling significantly and impacting the equipment after the tilt angle limiting structure loosens.

[0029] In some embodiments provided in this application, an environmental temperature control chamber 9 and a temperature acquisition component are also included. The environmental temperature control chamber 9 is a sealable cavity that covers the rotor hub test specimen and is used to provide a controllable temperature test environment. The temperature acquisition component includes a temperature sensor and a multi-channel temperature recorder. The temperature sensor is attached to the test area of ​​the rotor hub test specimen and electrically connected to the corresponding temperature recorder. The sealed and detachable temperature control chamber completely covers the rotor hub test specimen, enabling high-temperature environment simulation, expanding the test condition range, and completing static strength tests in multiple environments including normal temperature and high temperature, which is more in line with the full temperature range operating conditions of aircraft. The multi-point temperature sensor is attached to the key test area of ​​the specimen, and the multi-channel temperature recorder collects temperature data in real time, realizing multi-dimensional synchronous monitoring of load, stress, and temperature.

[0030] In some embodiments provided in this application, the waving drive component 57, the oscillation drive component 58, and the centrifugal drive component each integrate independent load sensing elements, and all load sensing elements are uniformly connected to the load data acquisition terminal. By equipping each of the waving drive component 57, the oscillation drive component 58, and the centrifugal drive component with independent load sensing elements, the real-time values ​​of each load can be collected independently, accurately distinguishing the contribution of the four types of loads, which facilitates the analysis of the impact of a single load on the hub structure; all sensors are uniformly connected to the same load acquisition terminal, and the four load data are recorded synchronously, realizing accurate classification and synchronous control of composite loads, avoiding overload of a single load; together with the strain acquisition of the load transmission rod 4, a dual load verification system is formed, which can verify the matching degree between the applied load and the stress of the rod in real time, promptly detect abnormalities such as tool slippage and loading eccentricity, and improve the reliability of the test.

[0031] Assembly and testing procedures for the static strength loading mechanism of the rotor hub system in this application: Step 1: Assemble the test bench base 1 with the specimen clamping fixture. The fixed seat 21 is rigidly connected to the flange of the test bench base 1 by multiple fastening bolts. After leveling the reference surface of the fixed seat 21 with a digital display inclinometer, all bolts are tightened. The hoisted rotor hub test piece is placed on the inclined contact surface inside the fixed base 21. The rotor hub test piece includes a star-shaped body 31, a straight clamping plate 32, a frequency matching device, and a pitch rocker arm 33. The upper pressure support 22 is fastened to the top of the rotor hub test piece, so that the inclined contact surface of the upper pressure support 22 is completely in contact with the upper surface of the test piece; multiple clamping bolts are inserted and simultaneously pass through the fixing seat 21, the rotor hub test piece, and the upper pressure support 22 and locked; additional reinforcement bolts are used to rigidly connect the upper pressure support 22 and the fixing seat 21 for a secondary connection to prevent the test piece from tilting or slipping during the loading process.

[0032] Step 2: Pre-treatment and docking assembly of load transmission rod 4 Attach strain acquisition elements to key areas of load transmission rod 4 and connect the strain acquisition element cables to static strain testing equipment; place load transmission rod 4 flat on a flat platform and zero out the strain values ​​under no-load conditions to eliminate measurement zero-point errors caused by the weight of the rod. The front end of the load transmission rod 4 is hinged to the straight clamp 32 of the rotor hub test piece by the blade pin, thus completing the mechanical connection between the load transmission rod and the test piece.

[0033] Step 3: Assembly of multi-directional load transfer fixture The main force transmission rod 51 is inserted through the end assembly hole of the load transmission rod 4, and the swinging adapter 52 is fitted on the outside of the main force transmission rod 51. The first-stage centrifugal adapter 54 is fitted onto the main force transmission rod 51, and the rear end of the first-stage centrifugal adapter 54 is connected to the second-stage centrifugal adapter 55 end to end through the threaded rod 56. The outer end of the main transmission rod 51 is equipped with a swinging connecting fork lug 53, which is connected to the swinging drive component 57; the oscillation adapter 52 is connected to the oscillation drive component 58 by a lateral threaded rod 56; the end of the secondary centrifugal adapter 55 is connected to the traction cable, and the other end of the traction cable is connected to the centrifugal drive component.

[0034] Step 4: Assembly of the variable pitch load loading assembly Use connecting bolts to fix one end of the flexible traction member 61 to the variable pitch rocker arm 33 of the rotor hub test piece; The flexible traction component 61 is moved upwards around the fixed pulley 62 installed on the test bench base 1, and the lower end of the flexible traction component 61 is suspended by the counterweight bearing component 63, ensuring that the counterweight bearing component 63 is completely suspended and has no ground support contact.

[0035] Step 5: Assemble the tilt angle limiting support structure The base plate 71 is fastened to the corresponding position on the test bench base 1 with bolts; The clamping support plate 72 is wrapped and attached to both sides of the load transmission rod 4; the fixed base plate 71 is pre-installed with a limiting right angle plate, the height of the right angle plate is adjusted to push the clamping support plate 72 upward and then locked, the load transmission rod 4 is constrained by the clamping support plate 72, and a fixed tilt angle of 4.5° is maintained. Assemble temporary support 8 and place it directly below the hinge node between load transmission rod 4 and straight clamp 32 to support the weight of load transmission rod 4 during the assembly stage.

[0036] Step 6: Temperature Control System Layout Temperature sensors were attached to key testing areas such as the star-shaped component of the rotor hub test piece, the straight clamp 32, and the variable pitch rocker arm 33, and the sensor cables were uniformly connected to a multi-channel temperature recorder. The hoisting environmental temperature control chamber 9 completely covers the entire rotor hub test piece. The chamber is fastened with buckles to form a sealed heating chamber. The chamber integrates heating elements, which can raise the temperature of the entire test piece.

[0037] Step 7: Equipment circuit debugging The load sensing elements of the waving drive component 57, the swing drive component 58, and the centrifugal drive component are uniformly wired and connected to the load data acquisition terminal. Check that the static strain testing equipment, multi-channel temperature recorder, and load acquisition terminal have stable circuit connections and that the equipment has no faults during power-on self-tests. Manually jog each drive component to extend and retract slightly to confirm that there is no motion interference or jamming in any of the various adapters or traction cables.

[0038] Step 8: Heating Pretreatment Set the target test temperature on the temperature control instrument and turn on the heating element inside the ambient temperature control chamber 9; observe the readings of the multi-channel temperature recorder in real time. After all measuring points of the specimen reach the test temperature and the temperature stabilizes, continue to keep it warm for the preset time. During the heat preservation period, inspect all tooling connection structures again to confirm that there is no loosening or deformation under high temperature conditions.

[0039] Step 9: Synchronous graded composite loading test Confirm that all four loading branches are zeroed, and record the strain, load, and initial zero-point temperature data. Synchronous loading is applied in stages according to rated loads of 20%, 40%, 60%, 80%, and 100%. The swing drive component 57, the pendulum drive component 58, and the centrifugal drive component output corresponding proportional loads simultaneously, while adding matching grade counterweights to the counterweight bearing component 63. Each load level is stabilized for a preset time, and stress, load, and temperature data are collected synchronously. The test pieces and tooling are visually inspected for deformation, cracks, and abnormal noises. After reaching 100% of the rated test load, the test specimen was kept under load for an extended period of time in accordance with the test outline requirements, and the data from each acquisition device was continuously monitored throughout the process to observe the specimen status in real time.

[0040] Step 10: Staged unloading and post-test processing After the load protection period ends, the four loads are unloaded synchronously in stages. First, the counterweight bearing component 63 is removed, and then the three sets of drive components are retracted to zero stroke in stages. Maintain the ambient temperature control chamber temperature by 9% and leave it unloaded for a preset time. Record the residual strain and residual deformation after unloading. Turn off the heating element in the chamber and wait for the test pieces and fixtures to cool down to room temperature naturally before removing the ambient temperature control chamber 9; In the reverse order of assembly, dismantle all kinds of transition tools, drive components, load transmission rod 4, and specimen clamping tools in sequence, and lift out the rotor hub test specimen to carry out non-destructive testing. Summarize all load, strain, and temperature test data, archive tooling and specimen inspection records, and complete the test.

[0041] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0044] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A static strength loading mechanism for a rotor hub system, characterized in that, include: Test bench base; The specimen clamping fixture is fixed on the test bench base. The specimen clamping fixture has an inclined contact surface that matches the installation tilt angle of the rotor hub test specimen. The specimen clamping fixture is used to hold and lock the rotor hub test specimen. The load transmission rod is hinged at one end to the straight clamping plate of the rotor hub test piece; A multi-directional load transfer fixture is connected to the other end of the load transmission rod. The multi-directional load transfer fixture is respectively connected to the swing drive component, the swing drive component, and the centrifugal drive component, and is used to synchronously transmit the swing load, the swing load, and the centrifugal load to the load transmission rod. The variable pitch load loading assembly is connected at one end to the rotor hub test piece, and at the other end is used to apply the variable pitch tie rod load to the rotor hub test piece. The waving drive, the swing drive, the centrifugal drive, and the counterweight bearing constitute four independent loading branches. The four loading branches can synchronously and gradedly output composite loads, and all loads act on the rotor hub test piece along the force axis of the rotor hub support arm.

2. The static strength loading mechanism for the rotor hub system according to claim 1, characterized in that, The specimen clamping fixture includes: The fixing seat is U-shaped; An upper pressure support is provided on one side of the inner wall of the fixed base. The upper pressure support and the other side of the inner wall of the fixed base form an inclined contact surface with the same inclination angle. The rotor hub test piece is clamped and confined between the two inclined contact surfaces.

3. The static strength loading mechanism for the rotor hub system according to claim 2, characterized in that, The fixed base is connected to the test bench base by fastening bolts; the fixed base, rotor hub test piece, and upper pressure support are locked together by clamping bolts; the upper pressure support and the fixed base are also connected by reinforcing bolts.

4. The static strength loading mechanism for the rotor hub system according to claim 1, characterized in that, The load transmission rod is equipped with strain acquisition elements, which are electrically connected to a static strain testing device.

5. The static strength loading mechanism for the rotor hub system according to claim 1, characterized in that, The multi-directional load transfer fixture includes a main force transmission rod, a swinging adapter, a swinging connecting fork lug, a primary centrifugal adapter, and a secondary centrifugal adapter; The main force transmission rod passes through the through assembly hole at the end of the centrifugal loading rod away from the rotor hub test piece; The oscillation adapter is sleeved on the outside of the main force transmission rod and connected to the oscillation drive component; The outer end of the main force transmission rod is connected to the waving drive component via the waving connecting fork lug; The primary centrifugal adapter is mounted on the main force transmission rod and connected to the secondary centrifugal adapter via a threaded rod. The end of the secondary centrifugal adapter is connected to the centrifugal drive via a traction cable.

6. The static strength loading mechanism for the rotor hub system according to claim 1, characterized in that, The variable pitch load loading assembly includes a flexible traction component, a fixed pulley, and a counterweight bearing component. One end of the flexible traction component is connected to the variable pitch rocker arm of the rotor hub test piece. After the flexible traction component passes around the fixed pulley on the test bench base, it suspends the counterweight bearing component to apply a variable pitch tie rod load to the rotor hub test piece.

7. The static strength loading mechanism for the rotor hub system according to claim 1, characterized in that, It also includes a fixed base plate and a clamping support plate. The fixed base plate is fixedly mounted on the test bench base, and the clamping support plate is fitted and covered on both sides of the load transmission rod to keep the load transmission rod at the same installation angle as the rotor hub arm.

8. The static strength loading mechanism for the rotor hub system according to claim 1, characterized in that, It also includes a temporary support, which is arranged below the hinge node between the load transmission rod and the straight clamp plate of the rotor hub test piece, and is used to support the load transmission rod during the assembly stage.

9. The static strength loading mechanism for the rotor hub system according to claim 1, characterized in that, It also includes an environmental temperature control chamber, which is a sealable cavity that covers the rotor hub test piece to provide a controllable temperature test environment; It also includes a temperature acquisition component, which includes a temperature sensor and a multi-channel temperature recorder. The temperature sensor is attached to the test area of ​​the rotor hub test piece and electrically connected to the corresponding temperature recorder.

10. The static strength loading mechanism for the rotor hub system according to claim 1, characterized in that, The waving drive, the swing drive, and the centrifugal drive each integrate an independent load sensing element, and all load sensing elements are uniformly connected to the load data acquisition terminal.

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