Device and method for testing fatigue performance of simulation part of lug connection rotation structure

Abstract

The invention belongs to the technical field of helicopter fatigue design, and discloses a device and method for testing the fatigue performance of a lug connection rotating structure simulation piece, and the device comprises a corner loading frame-shaped assembly, a connection bolt test piece, a double-lug structure simulation piece, an axial force loading assembly, and an installation fixing support. The mounting and fixing support is fixed on a test bed, the mounting and fixing support is provided with two groups of double-lug structures, the corner loading frame-shaped assembly is U-shaped, and two ends of the corner loading frame-shaped assembly are hinged with the two groups of double-lug structures through rotating bearings and cylindrical pins; one end of the double-lug structure simulation piece is a rectangular block, a fixing hole is formed in the middle of the double-lug structure simulation piece and serves as a fixing end, U-shaped symmetrical double lugs are symmetrically arranged above the fixing end relative to the fixing hole, and coaxial holes are formed in the U-shaped symmetrical double lugs; the fixed end of the double-lug structure simulation piece is fixedly connected with the corner loading frame-shaped assembly, and the loading end of the double-lug structure simulation piece is connected with the axial force loading assembly through a connecting bolt test piece; a single lug is arranged in the middle of the side edge of the corner loading frame, and a rotation loading bearing is arranged in the single lug.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopter fatigue design, and in particular relates to a fatigue performance testing device and method for a lug-connected rotating structure simulation part. Background Art

[0002] In helicopter rotor systems and other structures, ear connection structures are often used to transmit axial forces. The single ear is connected to the double ear through a spherical bearing and bolts and rotates during use. For such structural simulation parts, traditional fatigue performance tests only consider the axial force of the ear and ignore the influence of rotation during use. The fatigue performance results of the test will be much higher than the actual performance. Summary of the invention

[0003] Purpose of the invention: To provide a fatigue performance testing device and method for a simulated part of an ear-piece connection rotating structure. By using the method and device of the present invention to perform fatigue performance testing, a more accurate fatigue performance of the ear-piece connection rotating structure can be obtained, providing an experimental basis for its fatigue design and verification.

[0004] Technical Solution

[0005] A fatigue performance testing device for a lug-connected rotating structure simulation part, comprising: a rotation angle loading frame assembly, a connecting bolt test piece, a double lug structure simulation part, an axial force loading assembly, and an installation fixing support;

[0006] The mounting fixed support is fixed on the test bench. The mounting fixed support is provided with two sets of double-ear structures. The corner loading frame-shaped component is U-shaped as a whole. Both ends of the corner loading frame-shaped component are hinged with the two sets of double-ear structures through rotating bearings and cylindrical pins.

[0007] One end of the double-ear piece structure simulation part is a rectangular block with a fixing hole in the middle as the fixing end. U-shaped symmetrical double ears are symmetrically arranged above the fixing end about the fixing hole, and the U-shaped symmetrical double ears are provided with coaxial holes;

[0008] The fixed end of the double-ear structure simulation part is fixedly connected to the corner loading frame component, and the loading end is connected to the axial force loading component through the connecting bolt test piece;

[0009] A single ear is arranged in the middle of the corner loading frame side, and a rotation loading bearing is arranged in the single ear.

[0010] Furthermore, the two sets of double-ear structures for installing the fixed support are both provided with mounting holes adapted to the cylindrical pins;

[0011] The U-shaped ends of the corner loading frame assembly are provided with bearing holes, and rotating bearings are installed in the bearing holes;

[0012] The cylindrical pin passes through the mounting holes of the two groups of double-ear structures and the rotating bearing to realize the hinged connection between the mounting fixed support and the corner loading frame-shaped component.

[0013] Furthermore, one end of the cylindrical pin is an end cover, and a bolt hole is provided on an outer ear piece of the two sets of double-ear structures for installing and fixing the support, and the end cover and the outer ear piece are fixed by bolts.

[0014] Furthermore, the axial force loading assembly is composed of a single-ear structure simulation component and an axial force loading bearing. The axial force loading bearing is arranged in the single-ear structure simulation component. The axial force loading bearing and the U-shaped symmetrical double ears of the double-ear structure simulation component are connected by connecting bolt test pieces.

[0015] Furthermore, the fixed end of the double-ear structure simulation component is fixedly connected to the rotating loading frame assembly by means of fixing bolts.

[0016] A fatigue performance testing method for a lug-connected rotating structure simulation component, the steps are as follows:

[0017] Step 1: Determine the target structure of the fatigue performance test as a test piece, and the test piece includes one or more of a connecting bolt test piece, a single-ear piece structure simulation piece, and a double-ear piece structure simulation piece;

[0018] Step 2: From the fatigue limit-life curve of the axial force P, find the fatigue limit P corresponding to the target life of each failure mode ∞i ;

[0019] Step 3: According to the fatigue limit P ∞i The test load amplitude P of the design axial force P DT ;

[0020] Step 4: Design the test rotation angle amplitude;

[0021] Step 5: Design the phase difference between the test axial force P and the rotation angle.

[0022] Furthermore, in step 3, the test load amplitude P of the axial force P is designed. 0T The process is as follows:

[0023] According to the fatigue limit P ∞i , calculate the test load P required for each failure mode i =k×P ∞i / N α , k is the fatigue strength reduction factor, N is the target number of tests, and α is the fatigue curve shape parameter;

[0024] Test load amplitude P 0T Take the test load P required for each failure mode i The maximum value in .

[0025] Furthermore, in step 4, the process of designing the test rotation angle amplitude is as follows:

[0026] The angle spectrum of each rotation angle β, γ, θ is cut off from the low-load flight state, and the fatigue limit P of each failure mode is taken ∞i The minimum value P in ∞min , delete the axial force P not greater than P ∞min The flight status,

[0027] β is defined as the rotation along the axial direction of the connecting bolt test piece, γ is defined as the rotation along the axial direction of the single-ear structure simulation piece, and θ is defined as the rotation in the direction perpendicular to β and γ;

[0028] For the truncated β, γ, and θ angle spectra, the weighted average values ​​of the angle amplitudes β0, γ0, and θ0 are calculated respectively according to the proportion of flight time;

[0029] When γ0 and θ0 are smaller than β0, take the test rotation angle amplitude

[0030] When β0 and γ0 are smaller than θ0, take the test rotation angle amplitude

[0031] When γ0 is smaller than β0 and θ0, take the test rotation angle amplitude β OT =β0,

[0032] Furthermore, in step 5, the phase difference process of the test axial force P and the rotation angle is designed as follows:

[0033] The same low-load flight state truncation method and weighted average method as in step 4 are used to obtain the phase difference spectrum between the phase of the truncated axial force P and the phases of the three rotation angles β, γ, and θ, as well as the weighted average of the phase difference.

[0034] When γ0 and θ0 are smaller than β0, the test rotation angle amplitude is Take the test phase difference

[0035] When β0 and γ0 are smaller than θ0, the test rotation angle amplitude is Take the test phase difference

[0036] When γ0 is smaller than β0 and θ0, the amplitude of the test rotation angle is β OT =β0, When β OT ,θ OT Seek for power The weighted average of the experimental phase difference

[0037] When data is missing, take the phase difference between the test axial force P and the rotation angle as π / 2.

[0038] Further, when the first angle does not exceed 20% of the second angle, the first angle is considered to be smaller than the second angle.

[0039] In summary, the beneficial effects of the present invention are as follows:

[0040] The method and device of the present invention combine the rotation structure and load characteristics of the ear piece connection in the helicopter rotor system and other structures to perform the test boundary connection conditions and load loading design of the load and rotation coupling. The method and device of the present invention can accurately simulate the load and rotation boundary conditions of the test piece, the test bench is stable, the test environment is good, the load fluctuation is small, and the total test error can be controlled within 3%; accurate fatigue performance can be obtained, providing a test basis for structural fatigue design and verification evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a general schematic diagram of the test device for simultaneously applying the axial force P and the rotation angle β;

[0042] Figure 2 It is a front view of the test device for simultaneously applying the axial force P and the rotation angle β;

[0043] Figure 3 is a cross-sectional view of a test device for simultaneously applying an axial force P and a rotation angle β;

[0044] Figure 4 It is a general schematic diagram of the test device for simultaneously applying the axial force P and the rotation angle θ;

[0045] Figure 5 It is a front view of the test device for simultaneously applying the axial force P and the rotation angle θ;

[0046] Figure 6 is a cross-sectional view of a test device for simultaneously applying an axial force P and a rotation angle θ;

[0047] Figure 7 It is a general schematic diagram of the test device for simultaneously applying the axial force P and the rotation angles β and θ;

[0048] Figure 8 It is a front view of the test device for simultaneously applying the axial force P and the rotation angles β and θ;

[0049] Fig. 9 is a cross-sectional view of a test device for simultaneously applying an axial force P and rotation angles β and θ;

[0050] Fig.10 Schematic diagram of axial force and fatigue life curve. DETAILED DESCRIPTION

[0051] In the first aspect, a fatigue performance testing device for an ear-piece connected rotating structure simulation part is provided, and the testing device includes: an angle loading frame component 1, a connecting bolt test piece 2, a double ear-piece structure simulation part 3, a fixing bolt 4, an axial force loading component 5, a cylindrical pin 6, a fixing screw 7, and an installation fixing support 8.

[0052] Furthermore, the double-ear structure simulation component 3 is a test component, one loading end of which is connected to the axial force loading component 5 through the connecting bolt test component 2, and the other fixed end is connected to the angle loading frame component 1 through the fixing bolt 4; the interface design and assembly relationship of the connecting part among the connecting bolt test component 2, the axial force loading component 5 and the double-ear structure simulation component 3 are consistent with the actual structural state, the axial force is applied through the axial force loading component 5, and the rotation angle is applied through the rotation loading component 1, which truly simulates the connection assembly and load transfer relationship of the actual structural state.

[0053] Furthermore, the double-ear structure simulation part 3 is made of the same material as the test assessment structure, one end of which is the loading end and also the test assessment end, and is designed as a U-shaped symmetrical ear. The symmetrical ear is provided with a coaxial hole, and a wear protection bushing is installed in the symmetrical hole. The other end is a fixed end, which is rectangular and has a fixing hole symmetrical to the axis of the double ear. In order to fully verify the performance of the assessment end, the design strength of the fixed end should be higher than that of the assessment end.

[0054] Furthermore, the axial force loading component 5 is composed of a single ear structure simulation component 5-1 and an axial force loading bearing 5-2.

[0055] Furthermore, the rotating loading frame assembly 1 is composed of a loading frame 1-1, a rotating loading bearing 1-2, and a rotating bearing 1-3. The loading frame 1-1 is designed as a large U-shaped structure; a rectangular groove and two holes are opened on the bottom of the U-shaped structure to match the fixed end of the double-ear piece structure simulation component 3; a single ear piece is led out at a symmetrical position of the two holes on one side of the U-shaped bottom, and the single ear piece is provided with a hole to match the rotating loading bearing 1-2; the symmetrical ears on the side of the U-shaped structure are provided with axially symmetrical holes to match the two rotating bearings 1-3, and the center position of the hole is coaxial with the hole on the double ear piece of the double ear piece structure simulation component 3.

[0056] Furthermore, one end of the cylindrical pin 6 is cylindrical and adapted to the holes on the rotating bearing 1-3 and the mounting and fixing support 8, connecting the rotating loading frame component 1 and the mounting and fixing support 8 together; the other end is a circular end cover, which is provided with 4 holes that adapt to the threaded holes on the mounting and fixing support 8, and is fixed to the mounting and fixing support 8 by fixing screws 7, which can prevent the cylindrical pin 6 from axial movement and relative rotation.

[0057] Furthermore, the bottom plate of the mounting and fixing support 8 is provided with 8 holes which are fixed to the test bench by bolts, and two symmetrical U-shaped double-ear pieces are led out from the bottom plate, and the U-shaped double-ear pieces are provided with holes which are adapted to the cylindrical pins 6, and the groove in the middle of the U-shaped double-ear pieces is adapted to the width of the rotating bearing 1-3, and the outer ear pieces of the U-shaped double-ear pieces are provided with 4 threaded holes which are adapted to the cylindrical pins 6.

[0058] Furthermore, the test requires coordinated loading of two actuators. The axial force loading assembly 5 is connected to the horizontal actuator of the test bench to apply axial load to the structural simulation component. The upper ear of the rotation loading frame assembly 1 is connected to the vertical actuator of the test bench to push the double-ear structural simulation component 3 to rotate around the axis of the cylindrical pin 6 and the connecting bolt test piece 2. The rotation angle is controlled by the displacement of the vertical actuator. Before the formal test, the actuator displacement value corresponding to the calibrated rotation angle is measured by an inclinometer to determine the vertical actuator input displacement during the formal test.

[0059] Furthermore, the double-ear structure simulation component 3 is designed with different angles between the axis of the symmetrical ear holes and the axis of the fixing hole, so as to realize different test rotation angles required in the test method of the first aspect.

[0060] In a second aspect, a fatigue performance testing method for a simulated part of a lug-connected rotating structure is provided, and the steps are as follows:

[0061] [1] The target structure of the fatigue performance test is determined as a test piece, and the test piece includes one or more of a connecting bolt, a single-ear plate simulation piece, and a double-ear plate simulation piece;

[0062] [2] From the fatigue limit-life curve of the axial force P, find the fatigue limit P corresponding to the target life of each failure mode. ∞i ;

[0063] [3] Test load amplitude P of the design axial force P 0T ;

[0064] [4] Design the test rotation angle amplitude;

[0065] [5] Design the phase difference between the test axial force P and the rotation angle.

[0066] Furthermore, the step [3] designs the test load amplitude P of the axial force P 0T Method: According to step [2], the fatigue limit P ∞i , calculate the test load P required for each failure mode i =k×P ∞i / N α , k is the fatigue strength reduction factor, N is the target number of tests, α is the fatigue curve shape parameter; the test load amplitude P 0T Take the test load P required for each failure modei The maximum value in ;

[0067] Furthermore, the method for designing the test rotation angle amplitude in step [4] is as follows: the angle spectrum of each rotation angle β, γ, θ is truncated to the low-load flight state, that is, the fatigue limit P of each failure mode is taken ∞i The minimum value P in ∞min , delete the axial force P not greater than P ∞min The flight status,

[0068] β is defined as the rotation along the axial direction of the connecting bolt, γ is defined as the rotation along the axial direction of the single ear piece, and θ is defined as the rotation perpendicular to β and γ.

[0069] For the truncated β, γ, and θ angle spectra, the weighted average values ​​of the angle amplitudes β0, γ0, and θ0 are calculated respectively according to the proportion of flight time;

[0070] To reduce the difficulty of the test, the test rotation angle amplitude is taken when γ0 and θ0 are smaller than β0. When β0 and γ0 are smaller than θ0, take the test rotation angle amplitude When γ0 is smaller than β0 and θ0, the test rotation angle amplitude β 0T =β0,

[0071] Furthermore, the step [5] designs a method for testing the phase difference between the axial force P and the rotation angle: the same low-load flight state truncation method and weighted average method as step [4] are used to obtain the respective phase difference spectra between the phase of the truncated axial force P and the phases of the three rotation angles β, γ, and θ, as well as the weighted average of the phase difference.

[0072] In order to reduce the difficulty of the test, when γ0 and θ0 are smaller than β0, the amplitude of the test rotation angle is Take the test phase difference When β0 and γ0 are smaller than θ0, the test rotation angle amplitude is Take the test phase difference When γ0 is smaller than β0 and θ0, the amplitude of the test rotation angle is β OT =β0, When β OT ,θ OT Seek for power The weighted average of the experimental phase difference When data is missing, take the phase difference between the test axial force P and the rotation angle as π / 2.

[0073] Example

[0074] A fatigue performance testing method for a lug-connected rotating structure simulation component, the steps are as follows:

[0075] [1] If the target structure of the fatigue performance test is the connecting bolt, the single-ear simulation part and the double-ear simulation part, then the test pieces are the connecting bolt, the single-ear simulation part and the double-ear simulation part;

[0076] [2] From the fatigue limit-life curve of the axial force P (see Fig.10 ) and obtain the conditional fatigue limit P corresponding to the target life of 6000 hours for the two failure modes (aluminum alloy abrasion mode and alloy steel abrasion mode). ∞i They are 2868N and 3586N respectively;

[0077] [3] Test load amplitude P of the design axial force P 0T :k=2,N=0.001(×10 5 times), α is 0.0556 and 0.0370 respectively, then the test loads required for each failure mode are P1=8419.3N and P2=9264.0N; take the test load amplitude P 0T =9264.0N;

[0078] [4] Design the test rotation angle amplitude: For the angle spectrum of each rotation angle β, γ, and θ, delete the flight state where the axial force P is not greater than 2868N; for the β, γ, and θ angle spectrum after low load truncation, use the flight state time ratio as the weight to calculate the weighted average values ​​of the angle amplitudes β0, γ0, and θ0, which are 7.12°, 0.78°, and 0.36° respectively; γ0 and θ0 are smaller than β0, so the test rotation angle amplitude β 0T =7.17°;

[0079] [5] Design the phase difference between the test axial force P and the rotation angle: For the phase difference spectrum of the rotation angle β, delete the flight state where the axial force P is not greater than 2868N; for the phase difference spectrum of β after low load cutoff, calculate the weighted average value of the phase difference based on the proportion of flight state time. As the phase difference between the test axial force P and the rotation angle.

Claims

1. A fatigue performance testing device for a lug-connected rotating structure simulation component, characterized in that: The device comprises: a corner loading frame assembly, a connecting bolt test piece, a double-ear structure simulation piece, an axial force loading assembly, and an installation fixing support; The mounting fixed support is fixed on the test bench. The mounting fixed support is provided with two sets of double-ear structures. The corner loading frame-shaped component is U-shaped as a whole. Both ends of the corner loading frame-shaped component are hinged with the two sets of double-ear structures through rotating bearings and cylindrical pins. One end of the double-ear piece structure simulation part is a rectangular block with a fixing hole in the middle as the fixing end. U-shaped symmetrical double ears are symmetrically arranged above the fixing end about the fixing hole, and the U-shaped symmetrical double ears are provided with coaxial holes; The fixed end of the double-ear structure simulation part is fixedly connected to the corner loading frame component, and the loading end is connected to the axial force loading component through the connecting bolt test piece; A single ear is arranged in the middle of the corner loading frame side, and a rotation loading bearing is arranged in the single ear.

2. The device according to claim 1, characterized in that: The two sets of double-ear structures for installing the fixed support are both provided with mounting holes adapted to the cylindrical pins; The U-shaped ends of the corner loading frame assembly are provided with bearing holes, and rotating bearings are installed in the bearing holes; The cylindrical pin passes through the mounting holes of the two groups of double-ear structures and the rotating bearing to realize the hinged connection between the mounting fixed support and the corner loading frame-shaped component.

3. The device according to claim 2, characterized in that: One end of the cylindrical pin is an end cover, and a bolt hole is arranged on an outer ear piece of two sets of double-ear structures for installing and fixing the support, and the end cover and the outer ear piece are fixed by bolts.

4. The device according to claim 3, characterized in that: The axial force loading assembly consists of a single-ear structure simulation component and an axial force loading bearing. The axial force loading bearing is arranged in the single-ear structure simulation component. The axial force loading bearing and the U-shaped symmetrical double ears of the double-ear structure simulation component are connected by connecting bolt test pieces.

5. The device according to claim 4, characterized in that: The fixed end of the double-ear structure simulation component is fixedly connected to the rotating loading frame component by means of fixing bolts.

6. A fatigue performance testing method for a simulated part of a lug-connected rotating structure, implemented based on any of the above-mentioned devices, characterized in that: Here are the steps: Step 1: Determine the target structure of the fatigue performance test as a test piece, and the test piece includes one or more of a connecting bolt test piece, a single-ear piece structure simulation piece, and a double-ear piece structure simulation piece; Step 2: From the fatigue limit-life curve of the axial force P, find the fatigue limit P corresponding to the target life of each failure mode ∞i ; Step 3: According to the fatigue limit P ∞i The test load amplitude P of the design axial force P 0T ; Step 4: Design the test rotation angle amplitude; Step 5: Design the phase difference between the test axial force P and the rotation angle.

7. The method according to claim 6, characterized in that: In step 3, the test load amplitude P of the axial force P is designed. OT The process is as follows: According to the fatigue limit P ∞i , calculate the test load P required for each failure mode i =k×P ∞i / N α , k is the fatigue strength reduction factor, N is the target number of tests, and α is the fatigue curve shape parameter; Test load amplitude P OT Take the test load P required for each failure mode i The maximum value in .

8. The method according to claim 7, characterized in that: In step 4, the process of designing the test rotation angle amplitude is as follows: The angle spectrum of each rotation angle β, γ, θ is cut off from the low-load flight state, and the fatigue limit P of each failure mode is taken ∞i The minimum value P in ∞min , delete the axial force P not greater than P ∞min The flight status, β is defined as the rotation along the axial direction of the connecting bolt test piece, γ is defined as the rotation along the axial direction of the single-ear structure simulation piece, and θ is defined as the rotation in the direction perpendicular to β and γ; For the truncated β, γ, and θ angle spectra, the weighted average values ​​of the angle amplitudes β0, γ0, and θ0 are calculated respectively according to the proportion of flight time; When γ0 and θ0 are smaller than β0, take the test rotation angle amplitude When β0 and γ0 are smaller than θ0, take the test rotation angle amplitude When γ0 is smaller than β0 and θ0, take the test rotation angle amplitude β OT =β0, 9. The method according to claim 8, characterized in that: In step 5, the phase difference between the test axial force P and the rotation angle is designed as follows: The same low-load flight state truncation method and weighted average method as in step 4 are used to obtain the phase difference spectrum between the phase of the truncated axial force P and the phases of the three rotation angles β, γ, and θ, as well as the weighted average of the phase difference. When γ0 and θ0 are smaller than β0, the amplitude of the test rotation angle is The test phase difference When β0 and γ0 are smaller than θ0, the test rotation angle amplitude is The test phase difference When γ0 is smaller than β0 and θ0, the amplitude of the test rotation angle is β OT =β0, When β OT ,θ OT Seek for power The weighted average of the experimental phase difference When data is missing, take the phase difference between the test axial force P and the rotation angle as π / 2.

10. The method according to claim 9, characterized in that: When the first angle does not exceed 20% of the second angle, the first angle is considered to be smaller than the second angle.

Images