Tilt rotor static strength test device and method
By using angle-adjustable dummy components and genetic algorithms to optimize load combinations, the problem of load simulation for tiltrotor aircraft under different flight modes was solved, enabling reasonable load design and precise application, simplifying the testing process and reducing costs.
Patent Information
- Application Number
- CN202511907791.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies are insufficient to simulate the complex load conditions of tiltrotor aircraft in both helicopter and fixed-wing flight modes in the same test. Furthermore, traditional loading schemes require multiple adjustments, resulting in long test cycles and high costs.
An angle-adjustable dummy and optimization algorithm are used to simulate tilt angle changes, and a genetic algorithm is combined to optimize load combinations to achieve precise load application.
It enables the rational design and precise application of loads in tiltrotor aircraft, simplifies the testing process, and reduces testing costs and time.
Smart Images
Figure CN122009516A_ABST
Abstract
Description
[0001] Technical Field This invention belongs to the field of tilt rotor testing technology, specifically relating to a tilt rotor static strength testing device and method. Background Technology
[0002] A tiltrotor aircraft is a special type of aircraft that combines the vertical takeoff and landing capabilities of a helicopter with the high-speed flight of a fixed-wing aircraft. Its propulsion system typically consists of a tiltable rotor nacelle or spool, enabling switching between helicopter and fixed-wing flight modes. This unique operating method places complex and significantly different load environments on its structure, particularly the area where the tilting structure connects to its wings and fuselage, in both flight modes. This poses extremely high demands on the design and strength verification of the tiltrotor's tilting structure.
[0003] As the most direct and essential ground test method for verifying the structural load-bearing capacity of aircraft and ensuring flight safety, the rationality of the test method is directly related to the accuracy and reliability of the verification results. At present, the static strength test technology for conventional fixed-wing aircraft or helicopters is relatively mature. However, the static strength test of the tilt rotor structure faces challenges: (1) It is necessary to simulate two completely different load conditions, namely helicopter state and fixed-wing state, in the same test. The magnitude, direction and point of application of the load change greatly, and the coordination of application is difficult; (2) Simulating the boundary conditions of its in-flight load and achieving high-precision and synchronous application of complex loads (such as the combination of tension, torque, thrust and bending moment) on key components such as the rotor cabin is a difficult point in test design; (3) If the traditional single global loading scheme is adopted, in order to cover all critical conditions, it may be necessary to adjust the huge support and loading system multiple times, resulting in a long test cycle and high cost. Summary of the Invention
[0004] The purpose of this invention is to provide a tiltrotor static strength testing device and method. For the static strength test of the rotor cabin in a tiltrotor aircraft, an angle-adjustable dummy is used to meet the working condition assessment between helicopter mode and fixed-wing flight mode. At the same time, for the working condition load, an optimization algorithm is used to optimize the complex working condition load to achieve reasonable load design and facilitate accurate implementation of the test load.
[0005] The present invention provides a tilt rotor static strength testing device, comprising: an angle-adjustable dummy, the angle-adjustable dummy being used to simulate a tilt angle, wherein one end is loaded with a test load and the other end is connected to the test piece to be tested.
[0006] In one possible embodiment, the angle-adjustable dummy includes a tilt joint 11, a lead screw dummy 10, a universal joint assembly, a load loading platform 6, a left and right tilting structure fixing seat 1, and a lead screw structure fixing seat 2; the tilt joint 11 has a through hole in its center, the universal joint assembly is fixed in the through hole, and the lead screw dummy 10 passes through the threaded hole in the center of the universal joint assembly and is threadedly connected to the threaded hole; the tilt joint 11 has symmetrically fixed double-ear structures; the left and right tilting structure fixing seat 1 and the lead screw structure fixing seat 2 are respectively fixed to the bottom of the load loading platform 6 and are rotatably connected to the double-ear structure and the lug structure at one end of the lead screw dummy 10.
[0007] In one possible embodiment, the universal joint assembly includes a universal joint ring 3, a universal joint 4, and a flange 5; the flange 5 is fixed in the through hole by bolts, the universal joint ring 3 is concentrically arranged with the flange 5 and is rotatably connected by bolts; the universal joint 4 is concentrically arranged with the universal joint ring 3 and is rotatably connected by bolts; the universal joint 4 has a threaded through hole in its center, which is threadedly connected with the lead screw dummy 10.
[0008] In one possible embodiment, a loading connector 7 is also included, which is fixed in a loading hole on the surface of the load loading platform 6.
[0009] According to a second aspect of the present invention, a method for static strength testing of a tilting rotor is provided, employing the aforementioned tilting rotor static strength testing apparatus, comprising the following steps: Step 1: According to the dangerous load conditions, adjust the angle between the normal of the load loading platform 6 and the horizontal plane by rotating the lead screw dummy 10; Step 2: Predefine several load application points on the surface of the load loading platform 6; Step 3: Define the upper and lower boundaries of each load application point based on the preloaded tilt rotor load and the load magnitude at each load application point in Step 2; Step 4: Using the equilibrium equations, establish the objective function model within the bounded range of the upper and lower boundaries of each load application point determined in Step 2; Step 5: Using the objective function model established in Step 4, a genetic algorithm is used to calculate the combined load values applied at each load application point.
[0010] In one possible embodiment, the hazardous conditions include a helicopter mode, in which the angle between the normal of the load loading platform 6 and the horizontal plane is 90 degrees; a fixed-wing mode, in which the angle between the normal of the load loading platform 6 and the horizontal plane is 0 degrees; and a transition mode, in which the angle between the normal of the load loading platform 6 and the horizontal plane ranges from 0 degrees to 90 degrees.
[0011] In one possible embodiment, the specific process of determining a predefined number of load application points in step 2 includes: Select the projection point of the rotor center point on the load loading platform 6 as one of the load points. The positions of the remaining load points are determined according to the size of the loading hole. It is necessary to ensure that the distance between the loading hole and the edge of the load loading platform 6 is not less than 1.5 times the size of the hole to ensure that the loading hole will not be sheared.
[0012] In one possible embodiment, the specific process of defining the upper and lower boundaries of each load application point in step 3 includes: Lower boundary: The lower boundary of each load application point is determined by the minimum load that the load loading system of the laboratory can implement, i.e., F. min ≤F 系统min ; Upper Boundary: The upper boundary satisfies a principle: based on the hole diameter and edge distance of the loading holes on the load loading platform 6, the maximum shear stress and maximum normal stress of the local structure are calculated, considering at least a safety factor of 2. Then, the equivalent stress is calculated according to the fourth strength theory. The equivalent stress should be less than or equal to the material's ultimate strength. The calculation formula is as follows: , , ,in For shear stress, To load the load, For aperture, Maximum normal stress, To load platform thickness, The equivalent stress calculated based on the fourth strength theory, This represents the strength limit of the loading platform material.
[0013] In one possible embodiment, the specific process of establishing the objective function model in step 4 includes: Objective function model establishment: The first step is to establish the equivalent load balance equations for the load and moment at the rotor center based on the coordinates of the predefined load application points. The balance equations are as follows: ∑FXi =∑PX……………………………………………(1) ∑FYi =∑PY…………………………………………(2) ∑FZi =∑PZ…………………………………………(3) ∑Y1i ×FZi +∑Z1i ×FYi =∑MX………………………(4) ∑Z1i ×FXi +∑X1i ×FZi =∑MY………………………(5) ∑X1i ×FYi +∑Y1i ×FXi =∑MZ………………………(6) Where F Xi F Yi F Zi X is the load at the load application point; 1i Y 1i Z 1i Let be the coordinates of the dummy loading point, and i be the index of the loading point. ∑PX, ∑PY, ∑PZ, ∑MX, ∑MY, and ∑MZ represent the equivalent load and equivalent torque at the rotor center.
[0014] The second step is to express the established equivalent load balance equations in a matrix form. The equation set includes a coefficient matrix A and a constraint vector b, which provides the basis for subsequent calculations. The matrix form is as follows: A×Fi=b Where A is the coefficient matrix of the dummy loading point coordinates; Fi is the vector formed by the loads applied at each loading point; and b is the constraint vector formed by the equivalent load and equivalent torque at the rotor center.
[0015] The third step is to vectorize the upper and lower boundaries of each load application point. The upper and lower boundary vectors are as follows: Lb=[F1_min … Fi_min … Fn_min] Lu=[F1_max … Fi_ max … Fn_max] Where Lb is the vector of the lower limit of the load value at the load loading point, and Lu is the vector of the upper limit of the load value at the load loading point.
[0016] The fourth step is to determine the objective function, which is the residual of the equivalent load balance equation system. The objective function is as follows:
[0017] In one possible embodiment, step 5 specifically includes the following process: First, create a new script function in MATLAB, select the genetic algorithm as the optimization tool, use the fitness function of the algorithm as the objective function established in step four, use the constraint equation as the equivalent equilibrium equation established in step four, and use the boundary conditions as the upper and lower boundary vectors established in step four. Then, optimize the solution for the combined load values applied at each load application point.
[0018] The advantages of this invention are as follows: This method uses an angle-adjustable dummy for the static strength test of the rotor cabin in a tiltrotor aircraft, which allows the dummy to change any angle to meet the load loading angle requirements during the test conditions from helicopter mode to fixed-wing flight mode. At the same time, an optimization algorithm is used to optimize the complex test conditions for the load conditions, so as to achieve a reasonable design of the load direction and load magnitude, which facilitates the accurate and convenient implementation of the test load. Attached Figure Description
[0019] Figure 1A This is a top view of the helicopter mode angle adjustable dummy of the present invention; Figure 1B This is a front view of the helicopter mode angle-adjustable dummy of the present invention; Wherein: 1 is the left and right tilting structure fixing seat, 2 is the lead screw structure fixing seat 2, 3 is the universal joint ring, 4 is the universal joint, 5 is the flange, 6 is the load loading platform, 7 is the loading joint, 8 is the fixing bolt, 9 is the spherical bearing fixing bolt, 10 is the lead screw dummy, 11 is the tilting joint, 12 is the universal joint ring fixing bolt, and 13 is the universal joint fixing bolt. Figure 2 This is a schematic diagram of an adjustable-angle dummy for transition mode. Figure 3 This is a schematic diagram of an adjustable-angle dummy for fixed-wing configuration. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0021] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.
[0022] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0023] This invention provides a tilt rotor static strength testing device and method for static strength testing of various tilt rotor structures.
[0024] First, an adjustable dummy component is designed to address the characteristics of tilt rotors, such as... Figure 1A , Figure 1B As shown, the dummy component includes: left and right tilting structure fixing seat 1, lead screw structure fixing seat 2, universal joint ring 3, universal joint 4, flange 5, load loading platform 6, loading joint 7, fixing bolt 8, spherical bearing fixing bolt 9, lead screw dummy component 10, tilting joint 11, universal joint ring fixing bolt 12, and universal joint fixing bolt 13. The adjustable dummy is characterized by the following: the left and right tilting structure fixing seat 1 is hinged to the tilting joint by connecting bolts; the bottom surface of the left and right tilting structure fixing seat 1 is fixed to the loading installation platform 6 by fixing bolts; the lead screw structure fixing seat 2 is hinged to the joint bearing installed at the end of the lead screw dummy by the joint bearing fixing bolt 9; the bottom surface of the lead screw structure fixing seat 2 is fixed to the loading installation platform 6 by fixing bolts; one end of the lead screw dummy is connected to the lead screw structure fixing seat 2 by the joint bearing, and the other end is connected to the universal joint 4 by bolts; the universal joint is connected to the universal joint ring 3 by two bolts; the universal joint ring 3 is connected to the flange by two bolts; the flange is fixed to the tilting joint 11 by bolts; the entire system forms a statically determinate structure.
[0025] like Figure 2 , Figure 3 As shown, the adjustable-angle dummy component has the following motion characteristics: First, the universal joint can rotate freely relative to the universal joint ring around its connecting bolt; the universal joint ring can rotate freely relative to the flange around its connecting bolt; simultaneously, the motion axes between the universal joint-universal joint ring and the universal joint ring-flange are perpendicular to each other. The three components move in relation to each other, achieving 360-degree motion. By rotating the dummy screw component, the connection length between the universal joint and the screw structure fixing seat can be changed, thereby changing the tilt angle of the load loading platform. The rotating screw dummy component of the load loading platform can achieve arbitrary angle changes, ensuring the load loading angle requirements under different flight conditions.
[0026] To address the complex loads on the rotor, several load application points are predefined. The aim is to convert all rotor loads (forces and moments) to equivalent values at these predefined load application points on the load loading platform. Simultaneously, considering the feasibility of load application and the reasonableness of load magnitude, the load direction is set, and the upper and lower boundaries of the load magnitude are limited. This ensures that the load direction facilitates load application, and that the load magnitude, within the defined range, can not only be precisely applied through a coordinated loading system but also does not exceed the local energy limit of the structure at the load application point. Based on the predefined load application points, load direction, and upper and lower load limits, the following equilibrium equations are established between the loads applied at each loading point on the load loading platform and the equivalent load and equivalent moment at the rotor center: ∑FXi =∑PX……………………………………………(1) ∑FYi =∑PY…………………………………………(2) ∑FZi =∑PZ…………………………………………(3) ∑Yi ×FZi +∑Zi ×FYi =∑MX………………………(4) ∑Zi ×FXi +∑Xi ×FZi =∑MY………………………(5) ∑Xi ×FYi +∑Yi ×FXi =∑MZ………………………(6) Fxi_min≤FXi≤Fxi_max………………………………(7) Fyi_min≤FYi≤Fyi_max………………………………(8) Fzi_min≤FZi≤Fzi_max…………………………(9) Where F Xi F Yi F Zi X is the load at the load application point; i Y i Z i Let be the coordinates of the dummy loading point, and i be the index of the loading point. ∑PX, ∑PY, ∑PZ, ∑MX, ∑MY, and ∑MZ represent the equivalent load and equivalent torque at the rotor center. Fxi_min, Fyi_min, and Fzi_min are the upper limits of the load at the loading point, and Fxi_max, Fyi_max, and Fzi_max are the lower limits of the load at the loading point.
[0027] Based on the equilibrium equations (1) to (9), the expression form of the equality constraint matrix can be determined as follows: A×Fi=b………………………………(10) Lb=[F1_min…Fi_min…Fn_min]………………(11) Lu=[F1_max … Fi_ max … Fn_max] ………………(12) Where A is the coordinate matrix of the dummy loading point coordinates; Fi is the vector formed by the loads applied at each loading point; b is the vector formed by the equivalent load and equivalent torque at the rotor center. Lb is the vector of the upper limit of the load value at the loading point, and Lu is the vector of the lower limit of the load value at the loading point.
[0028] A mathematical model is established based on (10), (11), and (12), and the objective function is set to minimize the residual. Then, the optimization algorithm is performed to calculate and the solution with the minimum residual is selected from the Pareto solution set as the solution output.
[0029] Calculation example: The test conditions were in helicopter mode, with rotor center loads of: PX=373, PY=0, PZ=5245, MX=602500, MY=828750, and MZ=-1032500.
[0030] Predefined load points are 1, 2, and 3, with each load point having a bore diameter of Φ10. The minimum load that our laboratory can implement while ensuring a loading error of no less than 3% is 200N. In addition, based on the local strength calculation of the loading platform's loading holes, the maximum implementable load is 8000N while meeting a safety factor of no less than 2. The parameters of each loading point are shown in Table 1.
[0031] Table 1 Load Point Parameter List
[0032] The equilibrium equation is:
[0033] Coefficient matrix:
[0034] Constraint vector:
[0035] System of equations: A × x = b Lower bound vector:
[0036] Upper limit vector:
[0037] Fitness function:
[0038] After 51 iterations of the genetic algorithm, the optimal solution vector is: 。
Claims
1. A tilting rotor static strength testing device, characterized in that, include: An angle-adjustable dummy is used to simulate tilt angle, with one end loaded with a test load and the other end connected to the test piece to be tested.
2. The tilting rotor static strength testing device according to claim 1, characterized in that, The angle-adjustable dummy includes a tilt joint 11, a lead screw dummy 10, a universal joint assembly, a load loading platform 6, a left and right tilting structure fixing seat 1, and a lead screw structure fixing seat 2. The tilt joint 11 has a through hole in its center, and the universal joint assembly is fixed in the through hole. The lead screw dummy 10 passes through the threaded hole in the center of the universal joint assembly and is threadedly connected to the threaded hole. The tilt joint 11 has symmetrically fixed double-ear structures. The left and right tilting structure fixing seat 1 and the lead screw structure fixing seat 2 are respectively fixed to the bottom of the load loading platform 6 and are rotatably connected to the double-ear structure and the lug structure at one end of the lead screw dummy 10.
3. The tilting rotor static strength testing device according to claim 1, characterized in that, The universal joint assembly includes a universal joint ring 3, a universal joint 4, and a flange 5; the flange 5 is fixed in the through hole by bolts, the universal joint ring 3 is concentrically arranged with the flange 5 and is rotatably connected by bolts; the universal joint 4 is concentrically arranged with the universal joint ring 3 and is rotatably connected by bolts; the universal joint 4 has a threaded through hole in its center, which is threadedly connected with the lead screw dummy 10.
4. The tilting rotor static strength testing device according to claim 1, characterized in that, It also includes a loading connector 7, which is fixed in the loading hole on the surface of the load loading platform 6.
5. A method for static strength testing of a tilting rotor, characterized in that, The tilting rotor static strength testing device according to any one of claims 1-4 includes the following steps: Step 1: According to the dangerous load conditions, adjust the angle between the normal of the load loading platform 6 and the horizontal plane by rotating the lead screw dummy 10; Step 2: Predefine several load application points on the surface of the load loading platform 6; Step 3: Define the upper and lower boundaries of each load application point based on the preloaded tilt rotor load and the load magnitude at each load application point in Step 2; Step 4: Using the equilibrium equations, establish the objective function model within the bounded range of the upper and lower boundaries of each load application point determined in Step 2; Step 5: Using the objective function model established in Step 4, calculate the combined load values applied at each load application point using a genetic algorithm.
6. The method for static strength testing of a tilting rotor according to claim 5, characterized in that, The hazardous operating conditions include helicopter mode, where the angle between the normal of the load loading platform 6 and the horizontal plane is 90 degrees; fixed-wing mode, where the angle between the normal of the load loading platform 6 and the horizontal plane is 0 degrees; and transition mode, where the angle between the normal of the load loading platform 6 and the horizontal plane ranges from 0 degrees to 90 degrees.
7. The method for static strength testing of a tilting rotor according to claim 5, characterized in that, In step 2, the specific process of determining several predefined load application points includes: Select the projection point of the rotor center point on the load loading platform 6 as one of the load points. The positions of the remaining load points are determined according to the size of the loading hole. It is necessary to ensure that the distance between the loading hole and the edge of the load loading platform 6 is not less than 1.5 times the size of the hole to ensure that the loading hole will not be sheared.
8. The method for static strength testing of a tilting rotor according to claim 5, characterized in that, In step 3, the specific process of defining the upper and lower boundaries of each load application point includes: Lower boundary: The lower boundary of each load application point is determined by the minimum load that the load loading system of the laboratory can implement, i.e., F. min ≤F 系统min ; Upper Boundary: The upper boundary satisfies a principle: based on the hole diameter and edge distance of the loading holes on the load loading platform 6, the maximum shear stress and maximum normal stress of the local structure are calculated, considering at least a safety factor of 2. Then, the equivalent stress is calculated according to the fourth strength theory. The equivalent stress should be less than or equal to the material's ultimate strength. The calculation formula is as follows: , , ,in For shear stress, To load the load, For aperture, Maximum normal stress, To load platform thickness, The equivalent stress calculated based on the fourth strength theory, This represents the strength limit of the loading platform material.
9. The method for static strength testing of a tilting rotor according to claim 5, characterized in that, In step 4, the specific process of establishing the objective function model includes: Objective function model establishment: The first step is to establish the equivalent load balance equations for the load and moment at the rotor center based on the coordinates of the predefined load application points. The balance equations are as follows: ∑FXi =∑PX…………………………………………………(1) ∑FYi =∑PY………………………………………………(2) ∑FZi =∑PZ…………………………………………………(3) ∑Y1i ×FZi +∑Z1i ×FYi =∑MX…………………………(4) ∑Z1i ×FXi +∑X1i ×FZi =∑MY…………………………(5) ∑X1i ×FYi +∑Y1i ×FXi =∑MZ…………………………(6) Where F Xi F Yi F Zi X is the load at the load application point; 1i Y 1i Z 1i Let i be the coordinates of the loading point of the dummy component, and i be the index of the loading point; ∑PX, ∑PY, ∑PZ, ∑MX, ∑MY, and ∑MZ are the equivalent load and equivalent torque at the rotor center; The second step is to express the established equivalent load balance equations in a matrix form. The equation set includes a coefficient matrix A and a constraint vector b, which provides the basis for subsequent calculations. The matrix form is as follows: A×Fi=b Where A is the coefficient matrix of the coordinate values of the dummy loading point; Fi is the vector formed by the loads applied at each loading point; b is the constraint vector formed by the equivalent load and equivalent moment at the rotor center; The third step is to vectorize the upper and lower boundaries of each load application point. The upper and lower boundary vectors are as follows: Lb=[F1_min … Fi_min … Fn_min] Lu=[F1_max … Fi_ max … Fn_max] Where Lb is the vector of the lower limit of the load value at the load loading point, and Lu is the vector of the upper limit of the load value at the load loading point; The fourth step is to determine the objective function, which is the residual of the equivalent load balance equation system. The objective function is as follows: 。 10. The method for static strength testing of a tilting rotor according to claim 5, characterized in that, Step 5 specifically includes the following process: First, create a new script function in MATLAB, select the genetic algorithm as the optimization tool, use the fitness function of the algorithm as the objective function established in step four, use the constraint equation as the equivalent equilibrium equation established in step four, and use the boundary conditions as the upper and lower boundary vectors established in step four. Then, optimize the solution for the combined load values applied at each load application point.