A Loading Method for Fatigue Reliability Test Loads of Aircraft Movable Surfaces

Abstract

The present invention belongs to the technical field of aircraft wing surface fatigue testing, and discloses a method for loading test loads for the fatigue reliability of an aircraft movable wing surface. Obtain all the nodes of the movable wing surface at the current deflection angle and the corresponding aerodynamic loads for each node, the position of the center of pressure of the movable wing surface, as well as the resultant force error range and resultant moment error range of the loads; calculate the ratio of the total chordwise and vertical loads of the wing surface at the current deflection angle of the movable wing surface; select n proposed loading nodes at the suitable loading parts of the movable wing surface to simplify all N nodes; calculate the vertical load components and chordwise load components of all the proposed loading nodes; determine the resultant moment of all the proposed loading nodes in each direction; calculate the resultant force and resultant moment error after node simplification; if the errors are all within the error range, output the test load spectrum; solve the problem of difficult load simulation caused by the coupling of the load magnitude and the change of the loading point due to the movement of the movable wing surface.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft wing surface fatigue tests, and particularly relates to a method for loading test loads for the fatigue reliability of aircraft movable wing surfaces. Background Art

[0002] During use, movable wing surfaces are in a state of unfixed attitude, and often have movement modes such as retracting and extending along a fixed trajectory and multi-axis rotation. While they are moving, the aerodynamic loads on their surfaces are also changing accordingly. Therefore, when conducting fatigue reliability tests on the structures / machineries of aircraft movable wing surfaces, the test loads simulating aerodynamic forces applied to the wing surfaces are also constantly changing, and this change includes the load direction and the acting position. This change brings many difficulties to test loading.

[0003] Existing loading technologies for the fatigue reliability tests of movable wing surface structures and machineries usually simulate the dominant vertical aerodynamic load while ignoring the tangential aerodynamic load, and the load simulation is not accurate enough; a small number use independent loading devices to apply the tangential aerodynamic load, increasing the design, use costs and resources. Summary of the Invention

[0004] The technical problem solved by the present invention: The technical solution of the present invention proposes a method for loading test loads for the fatigue reliability of aircraft movable wing surfaces, which solves the problem of difficult load simulation caused by the coupling of the load magnitude and the change of the loading point brought about by the movement of the movable wing surface, can realize the simulation of test loads for single-point multi-axis, improves the accuracy of test loading, and is convenient for the design of test loading devices.

[0005] The technical solution of the present invention:

[0006] A method for loading test loads for the fatigue reliability of aircraft movable wing surfaces, the method comprising:

[0007] Step 1: Obtain all the nodes of the movable wing surface at the current deflection angle and the aerodynamic load corresponding to each node, the position of the center of pressure of the movable wing surface, as well as the resultant force error range and the resultant moment error range of the load; the total number of all the nodes is N;

[0008] Step 2: Calculate the ratio of the total chordwise and vertical loads of the wing surface of the movable wing surface at the current deflection angle;

[0009] Step 3: Select n proposed loading nodes P1...P at the suitable loading part of the movable wing surface n Simplify all the N nodes; n is much smaller than N;

[0010] Step 4: Calculate the vertical load components and chordwise load components of all the proposed loading nodes;

[0011] Step 5: Determine the resultant moment in each direction of all proposed loading nodes according to the sum of the chordwise load components and the sum of the vertical load components of all proposed loading nodes;

[0012] Step 6: Calculate the resultant force and the error of the resultant moment after node simplification;

[0013] Step 7: If both the resultant force and the error of the resultant moment in Step 6 are within the error range, output the test load spectrum;

[0014] Step 8: If either the resultant force or the error of the resultant moment in Step 6 is not within the error range, adjust the positions and quantities of the proposed loading nodes; repeat Steps 3 to 6 until the resultant force and the error of the resultant moment meet the requirements of the error range.

[0015] Furthermore, Step 2 is specifically as follows:

[0016] Obtain the sum of the chordwise and vertical components of the aerodynamic loads of all nodes of the movable wing surface, F X 、F Y ;

[0017] Establish a reference coordinate system S P0 parallel to the flap local coordinate system with the centroid position of the movable wing surface as the origin, and calculate the resultant moments M X 、M Y 、M Z ;

[0018] Calculate the ratio f = F X / F Y of the total chordwise and vertical loads of the movable wing surface at the current deflection angle.

[0019] Furthermore, in Step 3, the specific parts suitable for loading are:

[0020] The ribs inside the movable wing surface and the wing surface parts corresponding to the front and rear beams.

[0021] Furthermore, Step 4 is specifically as follows:

[0022] According to the principle of proximity, equivalent the aerodynamic loads of all nodes of the movable wing surface at the current deflection angle to the selected n proposed loading points P1...P n , to obtain the vertical load components F n ...F 1Y ...F nY on the n proposed loading points P1...P 1Y ...F nY , multiply the vertical load components F n ...F 1X ...F nX by f to obtain the chordwise load components F

[0023] Further, calculate the sum F' of the chordwise load components of all the proposed loading nodes X , and the sum F' of the vertical load components Y ;

[0024] According to the sum F' of the chordwise load components of all the proposed loading nodes X , and the sum F' of the vertical load components Y , determine the resultant moments M', P0 M', X M', Y M' Z on each axis of all the proposed loading nodes in the reference coordinate system S

[0025] Further, calculate the load error after node simplification, specifically:

[0026] The resultant force error in the X direction is: δ FX =(F X -F' X ) / F X

[0027] The moment error in the X direction is: δ MX =(M X -M' X ) / M X

[0028] The moment error in the Y direction is: δ MY =(M Y -M' Y ) / M Y

[0029] The moment error in the Z direction is: δ MZ =(M Z -M' Z ) / M Z .

[0030] Further, step 7 is specifically:

[0031] Combine the chordwise components and vertical components of each proposed loading node into a resultant force, and calculate the angle θ between the chordwise component of each proposed loading node and the resultant force, θ = arctan(1 / f);

[0032] Output the coordinates of each proposed loading node, as well as the chordwise component, resultant force and angle θ of each proposed loading node at the current deflection angle of the movable wing surface, to form a load spectrum file

[0033] Further, the method further includes:

[0034] Change the deflection angle of the movable wing surface in step 1 to obtain the test load spectra at different deflection angles

[0035] Further, a test loading device is designed according to the test load spectra at different deflection angles. The test loading device consists of an actuator adjusting device and a loading actuator. The loading actuator is used to perform load spectrum loading on the movable wing surface test piece according to the test load spectra at different deflection angles.

[0036] The technical solution of the present invention is to simulate the periodic and repetitive aerodynamic loads on the wing surface. The distributed aerodynamic loads are processed into multiple concentrated loads that can be tested and simulated. While meeting the requirements of load magnitude changes, it can also meet the requirements of loading point changes, achieve follow-up loading, and the load processing process is simple. This technology can be widely applied to structural mechanisms such as aircraft flaps, slats, and control surfaces. Description of the Drawings

[0037] Figure 1 It is a schematic flow chart of a method for loading test loads of the fatigue reliability of a movable wing surface of an aircraft provided by an embodiment of the present invention;

[0038] Figure 2 It is a schematic diagram of the test loading device provided by an embodiment of the present invention. Detailed Embodiments

[0039] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] According to the loads in three directions at each node of the movable wing surface of the aircraft, the technical solution of the present invention first assumes that the lateral load is relatively small compared to other directions and is ignored. Then, the chordwise load and the vertical load are processed to the selected loading points, and these loading points are preferably collinear. Calculate the ratio of the total chordwise load of the wing surface to the total vertical load, and use this ratio as the fixed coefficient for wing surface load processing. During processing, keep the vertical load at each loading point unchanged, and multiply it by the aforementioned fixed ratio coefficient respectively to obtain the chordwise load value, thereby completing the test load processing. The simultaneous simulation of the vertical load and the chordwise load at each loading point can be achieved by the rotation of a single actuator around the loading point.

[0041] The following further details the present invention. A method for loading test loads of the fatigue reliability of a movable wing surface of an aircraft provided by an embodiment of the present invention, as Figure 1 shown, includes:

[0042] Step 1: Input the aerodynamic loads at the wing surface nodes, the position of the center of pressure, and the load processing error limit;

[0043] Input the load components in three directions at each node of the wing surface, the center of pressure coordinates P0, and the allowable range of the resultant force of the load processing error δ F 、δ M .

[0044] Step 2: Calculate the ratio of the total chordwise and vertical loads of the wing surface;

[0045] Obtain the sum F X 、F Y of the aerodynamic loads of the wing surface nodes in the chordwise and vertical components; calculate the ratio f = F X / F Y . Establish a reference coordinate system S P0 (or a parallel reference coordinate system for other assessment parts) parallel to the local coordinate system of the flap with the center of pressure as the origin, and calculate the resultant moments M P0 、M X 、M Y 、M Z of each axis in this coordinate system.

[0046] Step 3: Select the nodes to be loaded;

[0047] Select n loading points P1...P n at the suitable loading parts of the wing surface.

[0048] Step 4: Calculate the vertical loads of all the proposed loading nodes according to the ratio in Step 2;

[0049] Equivalently distribute the aerodynamic loads of the wing surface nodes to the selected n loading points P1...P n according to the principle of proximity, and multiply their vertical load components F 1Y ...F nY by f to obtain the chordwise load components F 1X ...F nX .

[0050] Step 5: Calculate the resultant force and resultant moment of the center of pressure of the simplified wing surface in the chordwise and vertical directions;

[0051] Calculate the sum F′ X of the chordwise components of each simplified loading point; calculate the resultant moments M′ P0 、M′ X 、M′ Y 、M′ Z of each axis in the coordinate system S

[0052] Step 6: Calculate the error after load simplification;

[0053] Taking the result in Step 2 as a reference, calculate the error after load simplification according to the following formula,

[0054] δ FX =(F X -F′ X ) / F X

[0055] δ MX =(MX -M′ X ) / M X

[0056] δ MY =(M Y -M′ Y ) / M Y

[0057] δ MZ =(M Z -M′ Z ) / M Z

[0058] Step 7: Optimize the position and number of loading points;

[0059] If the simplified errors δ FX , δ MX , δ MY , δ MZ exceed the target value, then optimize the position or number of loading points.

[0060] Step 8: Repeat Steps 3 to 7 until the resultant force and resultant moment errors meet the target requirements;

[0061] After optimizing the position or number of loading points, repeat Steps 3 to 7 until the errors meet the target test requirements, and compensate for the moment if necessary.

[0062] Step 9: Combine the test loads;

[0063] After processing the optimized loads, combine the chordwise and vertical components of each loading point into a resultant force, and calculate the angle θ between the chordwise load component of each loading point and the resultant force, θ = arctan(1 / f).

[0064] Step 10: Output the test load spectrum.

[0065] Output the simplified loads and their parameters, including the coordinates of the selected loading points, and the loading components, resultant force, and angle θ, etc. of each loading point at different deflection angles of the movable wing surface, and form a load spectrum file, and design the servo loading device based on this.

[0066] Step 11: Design the test loading device.

[0067] Design the test loading device according to the test load spectrum, as Figure 2 shown, mainly including selecting or manufacturing appropriate loading actuators, loading actuator adjustment devices, etc.

[0068] Take the ratio of the total chordwise and vertical loads of the wing surface as the ratio of the chordwise and vertical loads of each loading point, and require the ratio of the chordwise and vertical loads of each loading point to be the same, which is conducive to the design and loading control of the loading device;

[0069] The chordwise load is processed with the ratio of the chordwise and vertical total loads of the wing surface as the ratio of the chordwise and vertical loads at each loading point, while keeping the vertical load unchanged, which is convenient for test load processing;

[0070] The chordwise load is processed with the ratio of the chordwise and vertical total loads of the wing surface as the ratio of the chordwise and vertical loads at each loading point, while keeping the vertical load unchanged, so that the test load is more accurate in the lift direction and reduces the influence brought by load processing in the main load direction.

[0071] The technical solution of the present invention solves the problem of the coupling between the loading points and the change of load magnitude during the loading process of the movable wing surface of the aircraft; the "method for processing test loads for the fatigue reliability test of the movable wing surface of the aircraft" only appropriately simplifies the drag and ensures the magnitude of the most important lift force of the movable wing surface; the "method for processing and loading test loads for the fatigue reliability test of the movable wing surface of the aircraft" considers the loads in two directions at the same time, improving the test loading accuracy and accuracy; the "method for loading the fatigue reliability test of the movable wing surface of the aircraft" realizes single-point bi-axial loading, solves the difficulties brought by the separate loading of bi-axial loads, and makes the design and implementation of the test device simple; for the "method for processing and loading test loads for the fatigue reliability test of the movable wing surface of the aircraft", the load ratios of the two axes are the same, which is convenient for load processing and test loading control; the "method for processing and loading test loads for the fatigue reliability test of the movable wing surface of the aircraft" has strong designability, universality, a wide application range, and forms the technical ability of follow-up loading for movable structural mechanisms.

Claims

1. A method for loading test loads of fatigue reliability of an aircraft movable wing surface, characterized in that, The method includes the following steps: Step 1: Obtain all the nodes of the movable wing surface at the current deflection angle, the aerodynamic load corresponding to each node, the position of the center of pressure of the movable wing surface, as well as the resultant force error range and resultant moment error range of the load; the total number of all the nodes is N; Step 2: Calculate the ratio of the total chordwise load to the total vertical load of the wing surface at the current deflection angle of the movable wing surface; Step 3: Select n proposed loading nodes P1...P at the parts of the movable airfoil suitable for loading n Simplify all N nodes; n is much smaller than N; Step 4: Calculate the vertical load components and chordwise load components of all the proposed loading nodes; Step 5: Determine the resultant moment of all the proposed loading nodes in each direction according to the sum of the chordwise load components and the sum of the vertical load components of all the proposed loading nodes; Step 6: Calculate the resultant force and resultant moment error after node simplification; Step 7: If both the resultant force and resultant moment errors in Step 6 are within the error range, output the test load spectrum; Step 8: If either the resultant force or the resultant moment error in Step 6 is not within the error range, adjust the positions and quantities of the proposed loading nodes; repeat Steps 3 to 6 until the resultant force and resultant moment errors meet the requirements of the error range.

2. A fatigue reliability test load loading method for an aircraft movable wing surface according to claim 1, characterized in that Step 2 specifically is: Obtain the sum of the chordwise and vertical components of the aerodynamic loads on all the nodes of the movable wing surface, \(F\)\( \) X , \(F\)\( \) Y ; A reference coordinate system S parallel to the local coordinate system of the flap is established with the centroid position of the movable wing surface as the origin P0 , and the resultant moments M X , M Y , and M Z about each axis in this coordinate system are calculated; Calculate the ratio f = F of the chordwise and vertical total loads of the movable wing surface at the current deflection angle X / F Y .

3. A method for loading test loads of fatigue reliability of an aircraft movable wing surface according to claim 1, characterized in that, In Step 3, the specifically suitable loading parts are: The ribs inside the movable wing surface, and the wing surface parts corresponding to the front and rear beams.

4. A fatigue reliability test load loading method for an aircraft movable wing surface according to claim 2, characterized in that Step 4 specifically is: According to the principle of proximity, the aerodynamic loads of all nodes of the movable wing surface at the current deflection angle are equivalent to the selected n proposed loading points P1...P n , obtaining n proposed loading points P1...P n with the vertical load components F 1Y ...F nY . Multiply the vertical load components F 1Y ...F nY by f to obtain the chordwise load components F n ...F 1X ...F nX on the n proposed loading points P1...P 5. A method for loading test loads for fatigue reliability of an aircraft movable wing surface according to claim 2, wherein Calculate the sum F X ' of the chordwise load components and the sum F Y ' of the vertical load components for all the proposed loading nodes; Determine the resultant moments M′ X ′, M′ Y ′ of all the proposed loading nodes about each axis in the reference coordinate system S P0 according to the sum F X ′ of the chordwise load components and the sum F Y ′ of the vertical load components of all the proposed loading nodes Z .​ 6. A fatigue reliability test load loading method for an aircraft movable wing surface according to claim 5, characterized in that, Calculating the load error after node simplification specifically is: The resultant force error in the X direction is: δ FX =(F X -F X ') / F X The moment error in the X direction is: δ MX =(M X - M' X ) / M X The moment error in the Y direction is: δ MY =(M Y - M' Y ) / M Y The moment error in the Z direction is: δ MZ =(M Z - M' Z ) / M Z .

7. A fatigue reliability test load loading method for an aircraft movable wing surface according to claim 2, characterized in that Step 7 specifically is: Combine the chordwise components and vertical components of each proposed loading node into a resultant force, and calculate the angle θ between the chordwise component of each proposed loading node and the resultant force, θ = arctan(1 / f); Output the coordinates of each proposed loading node, and the chordwise component, resultant force and angle θ of each proposed loading node at the current deflection angle of the movable wing surface to form a load spectrum file.

8. A method for loading test loads of fatigue reliability of an aircraft movable wing surface according to claim 1, characterized in that, The method further includes: Change the deflection angle of the movable wing surface in Step 1 to obtain test load spectra at different deflection angles.

9. A fatigue reliability test load loading method for an aircraft movable wing surface according to claim 8, characterized in that, Design a test loading device according to the test load spectra at different deflection angles. The test loading device consists of an actuator adjustment device and a loading actuator. The loading actuator is used to perform load spectrum loading on the movable wing surface test piece according to the test load spectra at different deflection angles.

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