Anti-torsion rod rocker fatigue test device and test method

Abstract

The present application belongs to the technical field of helicopter fatigue test, and discloses a torsion-proof rod rocker fatigue test device and test method. The device comprises a force transmission rod, a sliding pair mechanism, an axial torsion-proof load transmission mechanism, a double load transmission mechanism, a torque loading mechanism, a torsion-proof rod, a rocker, a constraint connecting rod and a rack. The axial load F is vertically loaded to the axial torsion-proof load transmission mechanism through the sliding pair mechanism by the force transmission rod, and then 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 transmission 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. One end of the torsion-proof rod is connected with the middle of the rocker, and the other end is fixed to the rack.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of helicopter fatigue test, and particularly relates to a torsion-proof rod rocker fatigue test device and a test method. BACKGROUND

[0002] There is no fatigue test device and test method for the torsion-proof rod rocker in China at present, and similar loading tooling can only meet the control of a single loading point and cannot meet the structure needs of the torsion-proof rod rocker at the same time. In addition, there is no test scheme conforming to the actual flight working condition characteristics of the torsion-proof rod rocker to check and verify the fatigue performance of the torsion-proof rod rocker.

[0003] In order to explore the fatigue performance of the helicopter torsion-proof rod rocker, the fatigue test of the torsion-proof rod rocker needs to be carried out on the ground, so as to determine the fatigue failure mode and dangerous position of the torsion-proof rod rocker. SUMMARY

[0004] The application aims to provide a torsion-proof rod rocker fatigue test device and a test method. In order to fully verify the fatigue performance and failure mode of the helicopter torsion-proof rod rocker, data support is provided for evaluating the fatigue life and structure development and design of the torsion-proof rod rocker.

[0005] TECHNICAL SCHEME

[0006] A torsion-proof rod rocker fatigue test device comprises a force transmission rod, a sliding pair mechanism, an axial anti-torsion transmission mechanism, a double transmission mechanism, a torque loading mechanism, a torsion-proof rod, a rocker, a constraint connecting rod and a rack.

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

[0008] The torque M is transmitted to the double transmission mechanism through the torque loading mechanism.

[0009] The double transmission 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.

[0010] One end of the torsion-proof rod is connected with the middle part of the rocker, and the other end is fixed to the rack.

[0011] Further, one end of the force transmission rod is connected to the output mechanism of the axial load F, 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 rack, and the sliding pair mechanism is coaxial with the torque loading mechanism.

[0013] The sliding pair mechanism has Z-direction sliding freedom and rotation freedom around the Z-direction.

[0014] The sliding pair mechanism also restricts the sliding freedom and rotation freedom of the axial anti-torsion transmission mechanism along the X and Y directions

[0015] Further, one end of the axial anti-torsion transmission mechanism is connected with the force transmission rod, and the other end is coaxially connected with the double transmission mechanism.

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

[0017] Further, the upper end of the double transmission mechanism is connected with the torque loading mechanism, the lower end is connected with the axial anti-torsion transmission mechanism, and the middle part is connected with 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-torsion transmission mechanism by fixed support, and is connected with the rocker by hinge support which only retains rotation freedom around the Y direction.

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

[0020] Further, the anti-torsion rod is a rod-shaped member with V-shaped ends and through holes at both ends, the lower end is connected with the rocker, and the upper end is connected with the rack.

[0021] The end connected with the rack only retains rotation freedom around the Y direction.

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

[0023] Further, the rocker is a rod-shaped member with A-shaped ends and through holes at both ends and in the middle, the lower end is connected with the double transmission mechanism, the upper end is connected with the constraint link, and the middle part is connected with the anti-torsion rod, and the three connection points only limit rotation freedom around the X and Z directions.

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

[0025] A method for anti-torsion rod rocker fatigue test, the method is based on the device implementation, comprising the following steps:

[0026] 1. Determine the load source of the anti-torsion rod rocker by measuring the rocker flight load 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 rotation blade acting on the rocker at the lower end of the rocker.

[0027] 2. The boundary conditions of the anti-torsion rod rocker are determined by load source analysis, the anti-torsion rod rocker is tested together to realize the equal stiffness simulation and the installation condition requirement of the freedom constraint, and the optimal boundary simulation requirement is achieved;

[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 rotation freedom of the anti-torsion rod around one end Y and the sliding freedom of the rocker along the X and Z directions are reserved;

[0029] 4. The axial force sheet is pasted in the middle position of the rod body of the anti-torsion rod to monitor the axial load, the torque sheet and the bending moment sheet are pasted in the middle position of the side to monitor the torque load and the lateral bending moment load, and the axial load, the torque load and the lateral bending moment load in the test process are collected in real time through the strain detector;

[0030] 5. The fatigue test termination condition of the anti-torsion rod rocker is that one or more of the torque load M or the axial load F cannot be normally loaded within the range of 3% error allowance, and the test needs to be terminated.

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

[0032] The anti-torsion rod rocker fatigue test device and test method provided by the present application can truly and accurately simulate the boundary conditions and load characteristics of the anti-torsion rod rocker of a helicopter, and realize the examination of the fatigue performance of the anti-torsion rod rocker. The fatigue test device is used for the fatigue test of the anti-torsion rod rocker, the test precision is high, the total error can be controlled within 3%, and the test result is true and accurate. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a schematic diagram of an anti-torsion rod rocker fatigue test device.

[0034] Figure 2 It is a schematic diagram of a rocker structure.

[0035] Figure 3 It is a schematic diagram of an anti-torsion rod structure.

[0036] Figure 4 It is a flow chart of an anti-torsion rod rocker fatigue test method. DETAILED DESCRIPTION

[0037] In the first aspect, the present application designs an anti-torsion rod rocker fatigue test loading device, and the device mainly comprises: a force transmission rod 1, a sliding pair mechanism 2, an axial anti-torsion load transmission mechanism 3, a double load transmission mechanism 4, a torque loading mechanism 5, an anti-torsion rod 6, a rocker 7, a constraint connecting rod 8 and a rack 9.

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

[0039] Further, the axial load F is loaded vertically by the force transmission rod 1 through the sliding pair mechanism 2 to the axial anti-torsion transmission mechanism 3, and then transmitted to the double transmission mechanism 4, and then the double transmission mechanism 4 is connected with the rocker 7, the rocker 7 is connected with the anti-torsion rod 6 and the constraint connecting rod 8 respectively, and the other end of the anti-torsion rod 6 and the constraint connecting rod 8 is fixed to the rack 9 respectively, so that the axial load F is smoothly transmitted to the anti-torsion rod 6 and the rocker 7. Further, 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 rod 6 and the rocker 7.

[0040] The coordinate system of the technical scheme of the application is shown in detail Figure 1 .

[0041] One end of the force transmission rod 1 is connected to the output mechanism of the axial load F, the other end is connected to the axial anti-torsion 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 when contacting with the sliding pair mechanism 2, so that the test process is not stuck and the load is smoothly transmitted.

[0042] The sliding pair mechanism 2 has the freedom of sliding along the Z direction and the freedom of rotating around the Z direction, while the freedom of sliding along the X and Y directions and the freedom of rotating around the X and Y directions are constrained.

[0043] The sliding pair mechanism 2 is fixed and constrained as a whole to the rack 9, so that the sliding pair mechanism 2 is coaxial with the torque loading mechanism 5, and at the same time, the axial load F is loaded vertically to the axial anti-torsion transmission mechanism 3 through the sliding pair mechanism 2, and during the loading process of the axial load F, there is no jamming and the loss is not more than 3%.

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

[0045] The connection end of the axial anti-torsion transmission mechanism 3 and the double transmission mechanism 4 has the freedom of rotating around the Z direction. At the same time, the sliding pair mechanism 2 constrains the axial anti-torsion transmission mechanism 3 along the X and Y directions and around the X and Y directions, so that the axial load F can be transmitted to the rocker 7 and the torque load cannot be transmitted.

[0046] The upper end of the double transmission mechanism 4 is connected with the torque loading mechanism 5, the lower end is connected with the axial anti-torsion transmission mechanism 3, and the middle part is connected with the rocker 7 along the Y direction. The double transmission mechanism 4 is connected with the torque loading mechanism 5 and the axial anti-torsion transmission mechanism 3 by fixed support, and the middle part is connected with the rocker 7 by hinge support which only retains the freedom of rotating around the Y direction.

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

[0048] The anti-torsion rod 6 is a rod-like member similar to a V shape with through holes at both ends, the lower end is connected with the rocker 7, and the upper end is connected with the frame 9. Among them, the connection with the frame 9 adopts an installation mode that only retains the rotational freedom around the Y direction, and the connection with the rocker 7 adopts an installation mode 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-like member similar to an A shape with through holes at both ends and in the middle, the lower end is connected with the double transmission mechanism 4, the upper end is connected with the constraint connecting rod 8, and the middle is connected with the anti-torsion rod 6. Among them, the three points only limit the rotational freedom around the X and Z directions.

[0050] The constraint connecting rod 8 is a rod-like structure with through holes at both ends, one end is connected with the rocker 7, and one end is connected with the frame 9. Among them, the connection with the frame 9 adopts an installation mode that only retains the rotational freedom around the Y direction, and the connection with the rocker 7 adopts an installation mode that only limits the rotational freedom around the X and Z directions.

[0051] The frame 9 is a stable and reliable support structure that can stably constrain the sliding pair mechanism 2, the torque loading mechanism 5, the anti-torsion rod 6, and the constraint connecting rod 8.

[0052] In the second aspect, the present application designs an anti-torsion rod rocker fatigue test method, the test method includes determining the anti-torsion rod rocker load source, the anti-torsion rod rocker boundary condition, and the anti-torsion rod load monitoring method.

[0053] 1. The determination of the anti-torsion rod rocker load source is through the actual flight load of the rocker under the helicopter level flight condition. In the anti-torsion rod rocker, the center position of the lower end of the rocker 7 is a rolling bearing, a main shaft is installed in the middle of the rolling bearing, and the main shaft is connected with the thrust propeller. Under the flight condition, due to the high-speed rotation of the thrust propeller, the air thrust generated by the propeller blades is transmitted to the rocker 7, and the high-speed rotation causes the radial friction force at the bearing connection of the main shaft to be transmitted to the rocker 7 through the strain technology. The actual rocker 7 load source is determined by monitoring the thrust propeller through strain technology, and the rocker 7 load has both the torque load M generated by the rotation load of the thrust propeller at the lower end of the rocker 7 and the axial load F generated by the thrust of the rotating propeller blades of the thrust propeller acting on the rocker. Since the torque load M and the axial load F are generated at the same time due to rotation, they have the same loading phase relationship.

[0054] 2. In combination with the determination of the load source of the anti-torsion rod rocker, the anti-torsion rod rocker boundary condition is analyzed by the load source, the rocker 7 needs to meet the installation condition of limiting rotation freedom degrees around X and Z directions only, and the stiffness simulation of the rocker constraint state needs to be consistent with the actual connection state, in combination with the need of synchronous fatigue test of the anti-torsion rod 6, it is judged that the installation condition requirement of the equal stiffness simulation and the freedom degree constraint can be realized by the joint examination of the anti-torsion rod rocker, and the best boundary simulation requirement is achieved.

[0055] 3. In combination with the load relationship of the anti-torsion rod rocker, since the torque load M and the axial load F are 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 the load application, the torque load M and the axial load F need to meet the non-interference and same-phase loading, and only the rotation freedom degree of the anti-torsion rod 6 around one end Y direction and the sliding freedom degree of the rocker 7 along X and Z directions are reserved.

[0056] 4. In combination with the examination method of the anti-torsion rod rocker, the specific load size borne by the anti-torsion rod 6 in the test process is determined, the axial load, the torque load and the lateral bending moment load of the anti-torsion rod 6 are monitored by the strain monitoring technology, therefore, the axial load is monitored by pasting the axial force sheet in the middle position of the rod body of the anti-torsion rod 6, the torque load and the lateral bending moment load are monitored by pasting the torque sheet and the bending moment sheet in the middle position of the side surface, the axial load, the torque load and the lateral bending moment load of the anti-torsion rod 6 are collected in real time by the strain detector during the test process, and the loads borne by the anti-torsion rod 6 are effectively obtained.

[0057] 5. The fatigue test termination condition of the anti-torsion rod rocker is that one or more loads of the torque load M or the axial load F cannot be normally loaded within the range of 3% error allowance, and the test is considered to have reached the damage condition and needs to be terminated.

[0058] When the anti-torsion rod rocker is tested, the boundary condition of the test piece can be accurately simulated, the test bed is stable, the test environment is good, the load fluctuation is small, the total error of the test can be controlled within 3% by using the device for testing, and the test data obtained by using the device can be used for life analysis, and the performance can be fully verified.

Claims

1. A torsion bar rocker fatigue test apparatus characterized by: The device comprises: 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 rod, a rocker, a constraint connecting rod, and a rack; an axial load F is vertically loaded to the axial anti-torsion transmission mechanism through the force transmission rod and the sliding pair mechanism, and then transmitted to the double transmission mechanism; the sliding pair mechanism has a Z-direction sliding degree of freedom and a Z-direction rotation degree of freedom; a torque M is transmitted to the double 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 connecting rod, and the other end of the constraint connecting rod is fixed to the rack; one end of the anti-torsion rod is connected to the middle of the rocker, and the other end is fixed to the rack; the anti-torsion rod is a V-shaped rod member with through holes at both ends, the lower end is connected to the rocker, and the upper end is connected to the rack; the end connected to the rack only has a Y-direction rotation degree of freedom; the end connected to the rocker only has a Y-direction rotation degree of freedom and an X-direction and Y-direction sliding degree of freedom; the rocker is an A-shaped rod member 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 connecting rod, and the middle is connected to the anti-torsion rod; all the three connection points only limit the X-direction and Z-direction rotation degrees of freedom; the constraint connecting rod is a rod structure with through holes at both ends, one end is connected to the rocker, and the other end is connected to the rack; the end connected to the rack only has a Y-direction rotation degree of freedom, and the end connected to the rocker only limits the X-direction and Z-direction rotation degrees of freedom.

2. The apparatus of claim 1, wherein: one end of the force transmission rod is connected to an output mechanism of the axial load F, 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.

3. The apparatus of claim 2, wherein: the sliding pair mechanism is fixed to the rack, and the sliding pair mechanism is coaxial with the torque loading mechanism; the sliding pair mechanism also restricts the X-direction and Y-direction sliding degrees of freedom and the X-direction and Y-direction rotation degrees of freedom of the axial anti-torsion transmission mechanism.

4. The apparatus of claim 3, wherein: 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 end of the axial anti-torsion transmission mechanism connected to the double transmission mechanism has a Z-direction rotation degree of freedom.

5. The apparatus of claim 4, wherein: the upper end of the double transmission mechanism is connected to the torque loading mechanism, the lower end is connected to the axial anti-torsion transmission mechanism, and the middle is connected to the rocker on both sides along the Y-direction; the double transmission mechanism is fixedly connected to the torque loading mechanism and the axial anti-torsion transmission mechanism, and the middle is hingedly connected to the rocker with only a Y-direction rotation degree of freedom.

6. The apparatus of claim 5, wherein: the torque loading mechanism is fixed to the rack and has a Z-direction sliding degree of freedom.

7. A method for anti-torsion bar rocker fatigue testing, said method being implemented on the basis of the device according to any one of claims 1-6, characterized in that: The method comprises the following steps:

1. determining the source of the rocker load of the anti-torsion rod through the actual measurement of the rocker flight load in the helicopter level flight condition; the rocker load comprises a torque load M generated by the thrust propeller rotation load at the lower end of the rocker and an axial load F generated by the thrust propeller blade acting on the rocker at the lower end of the rocker; 2. determining the boundary conditions of the anti-torsion rod rocker through load source analysis, testing the anti-torsion rod rocker together to realize the equal stiffness simulation and the installation condition requirement of the freedom constraint, and achieving the best boundary simulation requirement; 3. the torque load M and the axial load F need to be loaded without interference and in the same phase, and only the Y-direction rotation degree of freedom of the anti-torsion rod and the X-direction and Z-direction sliding degrees of freedom of the rocker are reserved.

4. Attach axial force plates to the middle position of the anti-torsion bar to monitor axial load, and attach torque and bending moment plates to the middle position of the side to monitor torque load and lateral bending moment load. Collect axial load, torque load, and lateral bending moment load in real time during the test using a strain gauge.

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

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