Anti-torsion bar rocker fatigue test device and test method

Abstract

The invention belongs to the technical field of helicopter fatigue tests, and discloses an anti-torsion bar rocker fatigue test device and test method. The device comprises a dowel bar, a sliding pair mechanism, an axial anti-torsion load transmission mechanism, a double load transmission mechanism, a torque loading mechanism, an anti-torsion bar, a rocker, a constraint connecting rod and a rack. An axial load F is vertically loaded to the axial anti-twist load transmission mechanism by the dowel bar through the sliding pair mechanism and then is transmitted to the double-load transmission mechanism; the torque M is transmitted to the double-load transmission mechanism through the torque loading mechanism; the double-load-transfer mechanism is connected with one end of the rocker, the other end of the rocker is connected with one end of the constraint connecting rod, and the other end of the constraint connecting rod is fixed to the rack. And the other end of the anti-torsion bar is fixed on the rack.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopter fatigue testing, and in particular relates to an anti-torsion bar rocker fatigue testing device and a testing method. Background Art

[0002] There are currently no relevant fatigue test devices and test methods for anti-torsion bar rockers in China. Similar loading fixtures can only meet the control of a single loading point and cannot simultaneously meet the structural needs of the anti-torsion bar rocker's tension and torsion. At the same time, there is no test plan that conforms to the actual flight conditions of the anti-torsion bar rocker to assess and verify the fatigue performance of the anti-torsion bar rocker.

[0003] In order to explore the fatigue performance of the helicopter anti-torsion bar rocker, it is necessary to carry out fatigue tests on the anti-torsion bar rocker on the ground to determine the fatigue failure mode and dangerous parts of the anti-torsion bar rocker. Summary of the invention

[0004] Purpose of the invention: To provide a fatigue test device and test method for a torsion bar rocker, in order to fully verify the fatigue performance and failure mode of a helicopter torsion bar rocker, and to provide data support for evaluating its fatigue life and structural development and design.

[0005] Technical Solution

[0006] An anti-torsion bar rocker fatigue test device, comprising: a force transmission rod, a sliding pair mechanism, an axial anti-torsion transmission mechanism, a double transmission mechanism, a torque loading mechanism, an anti-torsion bar, a rocker, a constraint link, and a test stand;

[0007] The axial load F is vertically loaded from the force transmission rod to the axial anti-torsion transmission mechanism through the sliding pair mechanism, and then transmitted to the double transmission mechanism;

[0008] The torque M is transmitted to the dual transmission mechanism through the torque loading mechanism;

[0009] The double transmission mechanism is connected to one end of the rocker, the other end of the rocker is connected to one end of the constraint link, and the other end of the constraint link is fixed to the platform;

[0010] One end of the anti-twist bar is connected to the middle part of the rocker, and the other end is fixed to the stand.

[0011] Furthermore, one end of the force transmission rod is connected to the output mechanism of the axial load F, and the other end is connected to the axial anti-torsion transmission mechanism, and the middle part is in frictional contact with the sliding pair mechanism.

[0012] Further, the sliding pair mechanism is fixed to the stand, and the sliding pair mechanism is coaxial with the torque loading mechanism;

[0013] The sliding pair mechanism has a sliding freedom in the Z direction and a rotation freedom around the Z direction;

[0014] The sliding pair mechanism also constrains the sliding freedom of the axial anti-torsion transmission mechanism along the X and Y directions and the rotational freedom around the X and Y directions.

[0015] Furthermore, one end of the axial anti-torsion transmission mechanism is connected to the force transmission rod, and the other end is coaxially connected to the double transmission mechanism;

[0016] The connecting end of the axial anti-torsion transmission mechanism and the double transmission mechanism has a rotational freedom around the Z direction.

[0017] Furthermore, the upper end of the double transmission mechanism is connected to the torque loading mechanism, the lower end is connected to the axial anti-twist transmission mechanism, and the middle is connected to the rocker on both sides along the Y direction;

[0018] The double transmission mechanism is connected with the torque loading mechanism and the axial anti-twist transmission mechanism by fixed supports, and the middle two sides are connected with the rocker by hinge supports which only retain the rotational freedom around the Y direction.

[0019] Furthermore, the torque loading mechanism is fixed to the platform and has sliding freedom along the Z direction.

[0020] Furthermore, the anti-twist bar is a V-shaped rod-shaped member with through holes at both ends, the lower end of which is connected to the rocker and the upper end of which is connected to the stand;

[0021] The end connected to the gantry only retains the degree of freedom of rotation around the Y direction;

[0022] The end connected to the rocker retains the rotational freedom around the Y direction and the sliding freedom along the X and Y directions.

[0023] Furthermore, the rocker is an A-shaped rod-shaped component with through holes at both ends and in the middle. The lower end is connected to the double transmission mechanism, the upper end is connected to the constraint link, and the middle is connected to the anti-twist bar. The three connection points only limit the rotational freedom around the X and Z directions.

[0024] Furthermore, the constraint link is a rod-shaped structure with through holes at both ends, one end is connected to the rocker, and the other end is connected to the frame; the end connected to the frame only retains the rotational freedom around the Y direction, and the end connected to the rocker only limits the rotational freedom around the X and Z directions.

[0025] A method for fatigue testing of a torsion bar rocker is implemented based on the device and comprises the following steps:

[0026] 1. Determine the source of the anti-torsion bar rocker load through the measured flight load of the rocker under the helicopter level flight condition; the rocker load includes: the torque load M generated by the thrust propeller rotation load at the lower end of the rocker, and the axial load F generated by the thrust propeller rotating blades at the lower end of the rocker acting on the rocker;

[0027] 2. Determine the boundary conditions of the anti-torsion bar and rocker through load source analysis, and test the anti-torsion bar and rocker together to achieve equal stiffness simulation and installation condition requirements of degree of freedom constraints, and achieve the best boundary simulation requirements;

[0028] 3. The torque load M and the axial load F need to be loaded without interference and in the same phase, and only the rotational freedom of the anti-torsion bar around one end in the Y direction and only the sliding freedom of the rocker along the X and Z directions are retained;

[0029] 4. Paste an axial force sheet in the middle of the anti-torsion bar to monitor the axial load, paste a torque sheet and a bending moment sheet in the middle of the side to monitor the torque load and lateral bending moment load, and use a strain detector to collect the axial load, torque load, and lateral bending moment load in real time during the test;

[0030] 5. The termination condition of the anti-torsion bar rocker fatigue test is that when one or more of the torque load M or axial load F can no longer be loaded normally within the allowable error range of 3%, the test is deemed to have reached the failure condition and the test needs to be terminated.

[0031] In summary, the beneficial effects of the present invention are as follows:

[0032] The invention proposes a torsion bar rocker fatigue test device and test method, which can truly and accurately simulate the boundary conditions and load characteristics of the helicopter torsion bar rocker, and realize the assessment of the fatigue performance test of the torsion bar rocker. The fatigue test device is used to perform the torsion bar rocker fatigue test, and the test accuracy is high, the total error can be controlled within 3%, and the test results are true and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figure is a schematic diagram of a torsion bar rocker fatigue test device.

[0034] Figure 2 Schematic diagram of the rocker structure.

[0035] Figure 3 This is a schematic diagram of the anti-twist rod structure.

[0036] Figure 4 The present invention is a flow chart of a fatigue test method for a torsion bar rocker. DETAILED DESCRIPTION

[0037] In the first aspect, the present invention designs a torsion bar rocker fatigue test loading device, which mainly includes: a force transmission rod 1, a sliding pair mechanism 2, an axial anti-torsion transmission mechanism 3, a double transmission mechanism 4, a torque loading mechanism 5, an anti-torsion bar 6, a rocker 7, a constraint link 8, and a test stand 9.

[0038] The anti-torsion bar and the rocker arm are test pieces.

[0039] Furthermore, the axial load F is vertically loaded from the force transmission rod 1 to the axial anti-torsion transmission mechanism 3 through the sliding pair mechanism 2, and then transmitted to the double transmission mechanism 4, and then the double transmission mechanism 4 is connected to the rocker 7, and the rocker 7 is respectively connected to the anti-torsion bar 6 and the constraint link 8, and the other ends of the anti-torsion bar 6 and the constraint link 8 are respectively fixed to the stand 9, so that the axial load F is smoothly transmitted to the anti-torsion bar 6 and the rocker 7. Furthermore, the axial anti-torsion transmission mechanism 3 does not have the function of transmitting torque, so the torque M is transmitted to the double transmission mechanism 4 through the torque loading mechanism 5, so that the torque M is smoothly transmitted to the anti-torsion bar 6 and the rocker 7.

[0040] The coordinate system of the technical solution of the present invention is described in detail in Figure 1 .

[0041] One end of the force transmission rod 1 is connected to the output mechanism of the axial load F, and the other end is connected to the axial anti-torsion load transmission mechanism 3, and the middle part is in contact with the sliding pair mechanism 2. The force transmission rod 1 has high surface finish, high surface hardness, and strong contact fatigue resistance, which ensures low friction and high contact fatigue resistance with the sliding pair mechanism 2, and realizes no jamming and smooth load transmission during the test process.

[0042] The sliding mechanism 2 has the sliding freedom along the Z direction and the rotational freedom around the Z direction, and simultaneously constrains the sliding freedom in the X and Y directions and the rotational freedom around the X and Y directions.

[0043] Among them, the sliding pair mechanism 2 is integrally constrained and fixed to the stand 9 to ensure that the sliding pair mechanism 2 is coaxial with the torque loading mechanism 5. At the same time, the axial load F is vertically loaded to the axial anti-torsion transmission mechanism 3 through the sliding pair mechanism 2. During the loading process of the axial load F, there is no jamming and the loss does not exceed 3%.

[0044] One end of the axial anti-torsion transmission mechanism 3 is connected to the force transmission rod 1 , and the other end is coaxially connected to the double transmission mechanism 4 .

[0045] The connection end of the axial anti-torsion transmission mechanism 3 and the dual transmission mechanism 4 has the freedom of rotation about the Z direction. At the same time, the sliding pair mechanism 2 constrains the sliding freedom of the axial anti-torsion transmission mechanism 3 along the X and Y directions and the freedom of rotation about the X and Y directions, so that the axial load F can be transmitted to the rocker 7 without transmitting the torque load.

[0046] The upper end of the double transmission mechanism 4 is connected to the torque loading mechanism 5, the lower end is connected to the axial anti-torsion transmission mechanism 3, and the middle is connected to the rocker 7 on both sides along the Y direction. The double transmission mechanism 4 is connected to the torque loading mechanism 5 and the axial anti-torsion transmission mechanism 3 by fixed support, and the middle two sides are connected to the rocker 7 by hinge support that only retains the rotational freedom around the Y direction.

[0047] The torque loading mechanism 5 is fixed to the stand 9 and is coaxially installed with the sliding pair mechanism 2 to ensure that the torque load M is smoothly transmitted to the double transmission mechanism 4. It has sliding freedom along the Z direction and cannot transmit axial load.

[0048] The anti-twist bar 6 is a rod-shaped member similar to a V-shape with through holes at both ends, the lower end of which is connected to the rocker 7, and the upper end is connected to the frame-type stand 9. The connection with the frame-type stand 9 adopts an installation method that only retains the rotational freedom around the Y direction, and the connection with the rocker 7 adopts an installation method that retains the rotational freedom around the Y direction and the sliding freedom along the X and Y directions.

[0049] The rocker 7 is a rod-shaped member similar to the A-type with through holes at both ends and in the middle, the lower end is connected to the double transmission mechanism 4, the upper end is connected to the constraint link 8, and the middle is connected to the anti-twist bar 6. Among them, the three points only limit the rotational freedom around the X and Z directions.

[0050] The constraint link 8 is a rod-shaped structure with through holes at both ends, one end of which is connected to the rocker 7 and the other end is connected to the frame 9. The connection with the frame 9 adopts an installation method that only retains the rotational freedom around the Y direction, and the connection with the rocker 7 adopts an installation method that only restricts the rotational freedom around the X and Z directions.

[0051] The stand 9 is a stable and reliable supporting structure, which can stably constrain the sliding pair mechanism 2, the torque loading mechanism 5, the anti-torsion rod 6, and the constraining connecting rod 8.

[0052] In a second aspect, the present invention designs a fatigue test method for an anti-torsion bar rocker, the test method comprising determining a load source of the anti-torsion bar rocker, a boundary condition of the anti-torsion bar rocker, and a load monitoring method for the anti-torsion bar.

[0053] 1. The source of the anti-torsion bar rocker load is determined by measuring the flight load of the rocker under the helicopter's level flight condition. In the anti-torsion bar rocker, the center position of the lower end of the rocker 7 is a rolling bearing, and a main shaft is installed in the middle of the rolling bearing, and the main shaft is connected to the thrust propeller. Under flight conditions, due to the high-speed rotation of the thrust propeller, the thrust along the air is generated by the thrust propeller blades and transmitted to the rocker 7. At the same time, the high-speed rotation causes the main shaft to generate radial friction at the bearing connection, and the axial load of the main shaft under the thrust propeller is monitored by strain technology and transmitted to the rocker 7 synchronously. The actual source of the rocker 7 load is determined by monitoring the thrust propeller through strain technology. The rocker 7 load includes both the torque load M generated by the thrust propeller rotation load at the lower end of the rocker 7 and the axial load F generated by the thrust propeller rotating blades at the lower end of the rocker 7. Since the torque load M and the axial load F are both generated simultaneously due to rotation, they have the same loading phase relationship.

[0054] 2. Combined with the above-mentioned determination of the load source of the anti-torsion bar rocker, the boundary conditions of the anti-torsion bar rocker are analyzed through the load source. The rocker 7 needs to meet the installation conditions of only limiting the rotational freedom around the X and Z directions. At the same time, the stiffness simulation of the rocker constraint state needs to be consistent with the actual connection state. Combined with the need to carry out fatigue tests on the anti-torsion bar 6 simultaneously, it is judged that the anti-torsion bar rocker can be evaluated together to achieve the equal stiffness simulation and freedom constraint installation condition requirements, thereby achieving the best boundary simulation requirements.

[0055] 3. Combined with the load relationship of the anti-torsion bar and rocker, since the torque load M and the axial load F are simultaneously loaded to the lower end of the rocker 7 and pass through the center of the lower end, in order to ensure the accuracy of load application, the torque load M and the axial load F must satisfy the requirements of non-interference loading and loading in the same phase, and only the rotational freedom of the anti-torsion bar 6 around one end in the Y direction and only the sliding freedom of the rocker 7 along the X and Z directions are retained.

[0056] 4. Combined with the anti-torsion bar rocker assessment method, in order to clarify the specific load size borne during the test, the anti-torsion bar 6 monitors the axial load, torque load, and lateral bending moment load of the anti-torsion bar 6 through strain monitoring technology. Therefore, an axial force sheet is pasted in the middle position of the rod body of the anti-torsion bar 6 to monitor the axial load, and a torque sheet and a bending moment sheet are pasted in the middle position of the side to monitor the torque load and lateral bending moment load. The axial load, torque load, and lateral bending moment load of the anti-torsion bar 6 are accurately collected in real time during the test through the strain detector, so as to effectively obtain the various loads borne by the anti-torsion bar 6.

[0057] 5. The termination condition of the anti-torsion bar rocker fatigue test is that when one or more of the torque load M or the axial load F cannot continue to be loaded normally within the allowable error range of 3%, the test is deemed to have reached the failure condition and the test needs to be terminated.

[0058] When testing, the present invention can accurately simulate the boundary conditions of the test piece, the test bench is stable, the test environment is good, and the load fluctuation is small. By using the device of the present invention to conduct tests, the total test error can be controlled within 3%. The test data obtained by the device of the present invention is used for life analysis, which can fully verify its performance.

Claims

1. A torsion bar rocker fatigue test device, characterized in that: The device includes: Force transmission rod, sliding pair mechanism, axial anti-torsion transmission mechanism, double transmission mechanism, torque loading mechanism, anti-torsion rod, rocker, restraint link, test bench; The axial load F is vertically loaded from the force transmission rod to the axial anti-torsion transmission mechanism through the sliding pair mechanism, and then transmitted to the double transmission mechanism; The torque M is transmitted to the dual transmission mechanism through the torque loading mechanism; The double transmission mechanism is connected to one end of the rocker, the other end of the rocker is connected to one end of the constraint link, and the other end of the constraint link is fixed to the platform; One end of the anti-twist bar is connected to the middle part of the rocker, and the other end is fixed to the stand.

2. The device according to claim 1, characterized in that: One end of the force transmission rod is connected to the output mechanism of the axial load F, and the other end is connected to the axial anti-torsion transmission mechanism, and the middle part is in friction contact with the sliding pair mechanism.

3. The device according to claim 2, characterized in that: The sliding pair mechanism is fixed to the platform, and the sliding pair mechanism is coaxial with the torque loading mechanism; The sliding pair mechanism has a sliding freedom in the Z direction and a rotation freedom around the Z direction; The sliding pair mechanism also constrains the sliding freedom of the axial anti-torsion transmission mechanism along the X and Y directions and the rotational freedom around the X and Y directions.

4. The device according to claim 3, characterized in that: One end of the axial anti-torsion transmission mechanism is connected to the force transmission rod, and the other end is coaxially connected to the double transmission mechanism; The connecting end of the axial anti-torsion transmission mechanism and the double transmission mechanism has a rotational freedom around the Z direction.

5. The device according to claim 4, characterized in that: The upper end of the double transmission mechanism is connected to the torque loading mechanism, the lower end is connected to the axial anti-twist transmission mechanism, and the middle is connected to the rocker on both sides along the Y direction; The double transmission mechanism is connected with the torque loading mechanism and the axial anti-twist transmission mechanism by fixed supports, and the middle two sides are connected with the rocker by hinge supports which only retain the rotational freedom around the Y direction.

6. The device according to claim 5, characterized in that: The torque loading mechanism is fixed to the stage and has sliding freedom along the Z direction.

7. The device according to claim 6, characterized in that: The anti-twist bar is a V-shaped rod-shaped member with through holes at both ends, the lower end is connected to the rocker, and the upper end is connected to the stand; The end connected to the gantry only retains the degree of freedom of rotation around the Y direction; The end connected to the rocker retains the rotational freedom around the Y direction and the sliding freedom along the X and Y directions.

8. The device according to claim 7, characterized in that: The rocker is an A-shaped rod-shaped component with through holes at both ends and in the middle. The lower end is connected to the double transmission mechanism, the upper end is connected to the constraint link, and the middle is connected to the anti-twist bar. The three connection points only limit the rotational freedom around the X and Z directions.

9. The device according to claim 8, characterized in that: The constraint link is a rod-shaped structure with through holes at both ends, one end of which is connected to the rocker and the other end is connected to the gantry; the end connected to the gantry only retains the rotational freedom around the Y direction, and the end connected to the rocker only limits the rotational freedom around the X and Z directions.

10. A method for fatigue testing of a torsion bar rocker, the method being implemented based on any of the above-mentioned devices, characterized in that: The following steps are involved:

1. Determine the source of the anti-torsion bar rocker load through the measured flight load of the rocker under the helicopter level flight condition; the rocker load includes: the torque load M generated by the thrust propeller rotation load at the lower end of the rocker, and the axial load F generated by the thrust propeller rotating blades at the lower end of the rocker acting on the rocker; 2. Determine the boundary conditions of the anti-torsion bar and rocker through load source analysis, and test the anti-torsion bar and rocker together to achieve equal stiffness simulation and installation condition requirements of degree of freedom constraints, and achieve the best boundary simulation requirements; 3. The torque load M and the axial load F need to be loaded without interference and in the same phase, and only the rotational freedom of the anti-torsion bar around one end in the Y direction and only the sliding freedom of the rocker along the X and Z directions are retained; 4. Paste an axial force sheet in the middle of the anti-torsion bar to monitor the axial load, paste a torque sheet and a bending moment sheet in the middle of the side to monitor the torque load and lateral bending moment load, and use a strain detector to collect the axial load, torque load, and lateral bending moment load in real time during the test; 5. The termination condition of the anti-torsion bar rocker fatigue test is that when one or more of the torque load M or axial load F can no longer be loaded normally within the allowable error range of 3%, the test is deemed to have reached the failure condition and the test needs to be terminated.

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