Ear tab connecting rotary structure simulation fatigue performance testing device and method

Abstract

The present application belongs to the technical field of helicopter fatigue design, and discloses a lug connecting rotating structure simulation fatigue performance testing device and method. The device comprises: a rotating angle loading frame assembly, a connecting bolt test piece, a double-lug structure simulation piece, an axial force loading assembly and a mounting and fixing support. The mounting and fixing support is fixed on a test bench, and is provided with two groups of double-lug structures. The rotating angle loading frame assembly is in a U shape, and the two ends of the rotating angle loading frame assembly are hinged to the two groups of double-lug structures through rotating bearings and cylindrical pins. The double-lug structure simulation piece is provided with a rectangular block at one end and a fixing hole in the middle, serving as a fixed end. A U-shaped symmetrical double lug is symmetrically arranged above the fixed end about the fixing hole, and the U-shaped symmetrical double lug is provided with a coaxial hole. The fixed end of the double-lug structure simulation piece is fixedly connected with the rotating angle loading frame assembly, and the loading end is connected with the axial force loading assembly through the connecting bolt test piece. A single lug is arranged in the middle of the side edge of the rotating angle loading frame, and a rotating loading bearing is arranged in the single lug.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of helicopter fatigue design, and particularly relates to an ear piece connecting rotating structure simulation fatigue performance testing device and method. BACKGROUND

[0002] Ear piece connecting structure is often used to transmit axial force in helicopter rotor system and other structures, and a single ear piece is connected with a double ear piece through a joint bearing and a bolt and rotates in use. For such a structure simulation, the traditional fatigue performance test only considers the axial force of the ear piece and ignores the influence of rotation in use, and the fatigue performance test result will be much higher than the actual use performance. SUMMARY

[0003] The application aims to provide an ear piece connecting rotating structure simulation fatigue performance testing device and method, which can obtain more accurate fatigue performance of the ear piece connecting rotating structure by using the method and device, and provide test basis for fatigue design and verification.

[0004] TECHNICAL SCHEME

[0005] An ear piece connecting rotating structure simulation fatigue performance testing device comprises a rotation angle loading frame assembly, a connecting bolt test piece, a double ear piece structure simulation piece, an axial force loading assembly and a mounting and fixing support.

[0006] The mounting and fixing support is fixed on a test bench, and the mounting and fixing support is provided with two groups of double ear structures. The rotation angle loading frame assembly is in a U shape as a whole, and the two ends of the rotation angle loading frame assembly are hinged to the two groups of double ear structures through rotating bearings and cylindrical pins.

[0007] The double ear piece structure simulation piece has a rectangular block at one end, and a fixing hole is arranged in the middle as a fixed end. A U-shaped symmetrical double ear is symmetrically arranged above the fixed end about the fixing hole, and the U-shaped symmetrical double ear is provided with a coaxial hole.

[0008] The fixed end of the double ear piece structure simulation piece is fixedly connected with the rotation angle loading frame assembly, and the loading end is connected with the axial force loading assembly through the connecting bolt test piece.

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

[0010] Further, the two groups of double ear structures of the mounting and fixing support are each provided with a mounting hole matched with the cylindrical pin.

[0011] The U-shaped two ends of the rotation angle loading frame assembly are provided with bearing holes, and rotating bearings are arranged in the bearing holes.

[0012] The cylindrical pin passes through the mounting holes of the two groups of double ear structures and the rotating bearings, so as to realize the hinging of the mounting and fixing support and the rotation angle loading frame assembly.

[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 part and an axial force loading bearing. The axial force loading bearing is arranged in the single-ear structure simulation part, and the axial force loading bearing and the U-shaped symmetrical double ears of the double-ear structure simulation part are connected by connecting bolts.

[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, comprising the following steps:

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

[0018] Step 2: From the fatigue limit-life curve of 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 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 coefficient, 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 experimental rotation angle amplitude is as follows:

[0026] The angle spectrum of each rotation angle β, γ, θ is cut off at 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 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 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 between the experimental 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 amplitude of the test rotation angle is Take the experimental phase difference

[0035] When β0 and γ0 are smaller than θ0, the amplitude of the test rotation angle is Take the experimental 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 Seeking 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, the first angle is considered to be relatively small when the first angle does not exceed 20% of the second angle.

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

[0040] The method and device of the present application combine the earpiece connecting rotating structure and load characteristics in the helicopter rotor system and other structures to perform the test boundary connection conditions and load loading design of load and rotating coupling. The test performed by using the method and device of the present application can accurately simulate the load and rotating 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 to provide test basis for structural fatigue design and verification evaluation. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 Overall schematic view of the test device for simultaneously applying axial force P and rotating angle β;

[0042] Figure 2 Front view of the test device for simultaneously applying axial force P and rotating angle β;

[0043] Figure 3 Cross-sectional view of the test device for simultaneously applying axial force P and rotating angle β;

[0044] Figure 4 Overall schematic view of the test device for simultaneously applying axial force P and rotating angle θ;

[0045] Figure 5 Front view of the test device for simultaneously applying axial force P and rotating angle θ;

[0046] Figure 6 Cross-sectional view of the test device for simultaneously applying axial force P and rotating angle θ;

[0047] Figure 7 Overall schematic view of the test device for simultaneously applying axial force P and rotating angles β, θ;

[0048] Figure 8 Front view of the test device for simultaneously applying axial force P and rotating angles β, θ;

[0049] Figure 9 Cross-sectional view of the test device for simultaneously applying axial force P and rotating angles β, θ;

[0050] Figure 10 Schematic view of the axial force and fatigue life curve. DETAILED DESCRIPTION

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

[0052] Further, the double ear piece structure simulation piece 3 is a testing piece, one end of which is connected to the axial force loading assembly 5 through the connecting bolt testing piece 2, and the other end is connected to the rotating angle loading frame assembly 1 through the fixing bolt 4; the connecting relationship and assembly relationship of the connecting bolt testing piece 2, the axial force loading assembly 5 and the connecting part of the double ear piece structure simulation piece 3 are consistent with the real structure state, the axial force is applied through the axial force loading assembly 5, and the rotating angle is applied through the rotating loading assembly 1, so as to simulate the real connection assembly and load transmission relationship of the real structure state.

[0053] Further, the double ear piece structure simulation piece 3 is made of the same material as the testing and evaluation structure, one end of which is a loading end and a testing and evaluation end, and is designed as a U-shaped symmetrical ear piece, a coaxial hole is arranged on the symmetrical ear piece, and a wear protection bushing is assembled in the symmetrical hole, the other end is a fixing end, which is a rectangle, and a fixing hole symmetrical to the double ear piece axis is arranged on the fixing end; in order to fully verify the performance of the evaluation end, the design strength of the fixing end should be higher than that of the evaluation end.

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

[0055] Further, 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 slot and two holes are arranged on the bottom of the U-shaped structure and are adapted to the fixing end of the double ear piece structure simulation piece 3, a single ear piece is led out on the symmetrical position of the two holes on one side of the bottom of the U-shaped structure, the single ear piece is provided with a hole and is adapted to the rotating loading bearing 1-2, axis-symmetrical holes are arranged on the symmetrical ear pieces of the side surface of the U-shaped structure and are adapted to the two rotating bearings 1-3, and the center positions of the holes are coaxial with the holes on the double ear pieces of the double ear piece structure simulation piece 3.

[0056] Further, one end of the cylindrical pin 6 is a cylinder and is adapted to the holes on the rotating bearing 1-3 and the mounting fixing support 8, so as to connect the rotating loading frame assembly 1 and the mounting fixing support 8 together, the other end is a circular end cover, four holes are arranged on the end cover and are adapted to the threaded holes on the mounting fixing support 8, the mounting fixing support 8 is fixed on the mounting fixing support 8 through the fixing screw 7, and the axial movement and relative rotation of the cylindrical pin 6 can be prevented.

[0057] Furthermore, the bottom plate of the mounting and fixing support 8 is provided with 8 holes and fixed to the test bench by bolts, and two symmetrical U-shaped double-ear pieces are led out from the bottom plate. The U-shaped double-ear pieces are provided with holes 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 bearings 1-3, and the outer ear pieces of the U-shaped double-ear pieces are provided with 4 threaded holes 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 part; 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 part 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 and calibrated 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 hole 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 lug-connected rotating structure simulation component is provided, wherein the steps are as follows:

[0061] [1] The target structure of the fatigue performance test is determined as the test piece, and the test piece includes one or more of the following: 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 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 coefficient, 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 of designing the test rotation angle amplitude in step [4] is as follows: the angle spectrum of each rotation angle β, γ, θ is cut off from 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 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, 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] In order 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: using the same low-load flight state truncation method and weighted average method as step [4], 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 are obtained respectively.

[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 experimental phase difference

[0073] When β0 and γ0 are smaller than θ0, the amplitude of the test rotation angle is Take the experimental phase difference

[0074] When γ0 is smaller than β0 and θ0, the amplitude of the test rotation angle is β OT =β0, When β OT ,θ OT Seeking power The weighted average of the experimental phase difference

[0075] When data is missing, take the phase difference between the test axial force P and the rotation angle as π / 2.

[0076] Example

[0077] A fatigue performance testing method for a lug-connected rotating structure simulation component, comprising the following steps:

[0078] [1] If the target structures for fatigue performance testing are connecting bolts, single-ear plate simulation parts and double-ear plate simulation parts, then the test pieces are connecting bolts, single-ear plate simulation parts and double-ear plate simulation parts;

[0079] [2] From the fatigue limit-life curve of axial force P (see Figure 10 ), find out 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;

[0080] [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;

[0081] [4] Design the test rotation angle amplitude: for the angle spectrum of each rotation angle β, γ, θ, delete the flight state where the axial force P is not greater than 2868N; for the angle spectrum of β, γ, θ after low load truncation, use the flight state time ratio as the weight to calculate the weighted average values ​​of each angle amplitude β0, γ0, 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°;

[0082] [5] Design the phase difference between the axial force P and the rotation angle of the test: 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 according to the proportion of the flight state time. As the phase difference between the test axial force P and the rotation angle.

Claims

1. A device for testing the fatigue performance of a flap jointed rotary structure mockup, 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 a mounting and fixing support; The mounting and fixing support is fixed on a test bench, and the mounting and fixing support is provided with two groups of double-ear structures; the corner loading frame assembly is in a U shape as a whole, and the two ends of the corner loading frame assembly are hinged to the two groups of double-ear structures through rotating bearings and cylindrical pins; The double-ear structure simulation piece is provided with a rectangular block at one end and a fixing hole in the middle, serving as a fixed end; a U-shaped symmetrical double-ear is symmetrically arranged above the fixing hole; and the U-shaped symmetrical double-ear is provided with a coaxial hole; The fixed end of the double-ear structure simulation piece is fixedly connected to the corner loading frame assembly, and the loading end is connected to the axial force loading assembly through the connecting bolt test piece; A single ear is arranged in the middle of the side edge of the corner loading frame assembly, and a rotating loading bearing is arranged in the single ear.

2. The apparatus of claim 1, wherein: The two groups of double-ear structures of the mounting and fixing support are each provided with a mounting hole matched with the cylindrical pin; The two ends of the U-shaped corner loading frame assembly are provided with bearing holes, and rotating bearings are arranged in the bearing holes; The cylindrical pin passes through the mounting holes of the two groups of double-ear structures and the rotating bearings, thereby realizing the hinging of the mounting and fixing support and the corner loading frame assembly.

3. The apparatus of claim 2, wherein: One end of the cylindrical pin is an end cover, one ear piece outside the two groups of double-ear structures of the mounting and fixing support is provided with a bolt hole, and the end cover and the one ear piece outside are fixed through a bolt.

4. The apparatus of claim 3, wherein: The axial force loading assembly is composed of a single-ear structure simulation piece and an axial force loading bearing; the axial force loading bearing is arranged in the single-ear structure simulation piece; and the axial force loading bearing and the U-shaped symmetrical double-ear of the double-ear structure simulation piece are connected through the connecting bolt test piece.

5. The apparatus of claim 4, wherein: The fixed end of the double-ear structure simulation piece is fixedly connected to the rotating loading frame assembly through a fixing bolt.

6. A method of testing the fatigue performance of a tab-connecting rotary structure mockup, implemented on the basis of the device according to any one of the preceding claims, characterized in that: The steps are as follows: Step one: determining a target structure for fatigue performance test as a test piece, the test piece including one or several of a connecting bolt test piece, a single-ear structure simulation piece and a double-ear structure simulation piece; Step two: from the fatigue limit-life curve of axial force P, the fatigue limit P corresponding to the target life of each failure mode is obtained ∞i ; Step three: according to the fatigue limit P ∞i Design test load amplitude P of axial force P 0T ; Step four: designing a test rotating angle amplitude; Step five: designing a phase difference between a test axial force P and a rotating angle.

7. The method of claim 6, wherein: In step three, 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 coefficient, N is the target number of tests, and α is the fatigue curve shape parameter; Test load amplitude P OT Take the maximum value in the test load P i required for each failure mode.

8. The method of claim 7, wherein: In step four, the process of designing the test rotating angle amplitude is as follows: The angle spectrum of each rotation angle β, γ, θ is truncated for low load flight state, and the minimum value P ∞i of each failure mode fatigue limit P ∞min is taken, and the flight state with axial force P not greater than P ∞min is deleted, β is defined as a rotation along the axial direction of the connecting bolt test piece, γ is defined as a rotation along the axial direction of the single-ear structure simulation piece, and θ is defined as a rotation in a direction perpendicular to β and γ; For the β, γ and θ angle spectrum after cutting, the weighted average values β0, γ0 and θ0 of the respective angle amplitudes are respectively calculated according to the flight state time ratio as the weight; When γ0, θ0are smaller than β0, take the test rotation angle amplitude When β0, γ0are smaller than θ0, take the test rotation angle amplitude When γ0is smaller than β0, θ0, take the test rotation angle amplitude β OT = β0, 9. The method of claim 8, wherein: In step five, the process of designing the phase difference between the test axial force P and the rotating angle is as follows: Using the same low-load flight state cut-off method and weighted average method as in Step Four, the phase difference spectrum of each of the phase of the cut-off axial force P and the phase of the rotation angles β, γ, θ, and the weighted average value of the phase difference are obtained, respectively When γ0, θ0 are smaller than β0, the test rotation angle amplitude is taken as the test phase difference When β0, γ0are smaller than θ0, the test rotation angle amplitude is taken as the test phase difference When γ0is smaller than β0, θ0, the test rotation angle amplitude is taken as β OT = β0, = β0, OT , θ OT , and the weighted average value of β , θ When the data is missing, the phase difference between the test axial force P and the rotating angle is taken as π / 2.

10. The method of claim 9, wherein: When the first angle is not more than 20% of the second angle, the first angle is considered to be relatively small relative to the second angle.

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