Airplane airfoil torque high-precision measurement method
By arranging strain sensors and designing torque calibration test conditions on the aircraft wing surface, a high-precision torque measurement load equation is established using bonded load pads and hydraulic servo actuators, which solves the problem of large error in the aircraft wing surface torque load measurement, and achieves high-precision measurement, with the error reduced from 20% to 7%.
Patent Information
- Application Number
- CN202411951702.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-04-15
AI Technical Summary
The prior art has large errors in the measurement of torque loads on the aircraft wing surface, making it difficult to achieve high-precision measurements. Especially on large wingspan flexible wings, torque loads are of great significance to structural load verification and aircraft rudder surface control characteristics.
By arranging strain sensors on the aircraft wing torque load bearing path, designing the airfoil torque calibration test conditions, and connecting the loading pad with the loading equipment through bonding at the lower airfoil loading point, the pulling/pressure loading of the vertical airfoil is carried out using a hydraulic servo actuator to establish a high-precision torque measurement load equation.
The torque calibration load order is significantly improved, the bearing requirements of test-constrained equipment are reduced, and the problem of poor accuracy of airfoil torque measurement is solved. The error is reduced from 20% to 7%, meeting the needs of high-precision measurement.
Smart Images
Figure CN119827028A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of structural load measurement in aircraft flight tests, and in particular relates to a high-precision measurement method for aircraft wing surface torque. Background Art
[0002] Aircraft flight load measurement is an important test item for military aircraft design finalization or civil aircraft qualification certification. Generally, the accuracy of the design load calculation and analysis method is verified by measuring the total load of bending moment, shear force and torque outside the specified section of the wing. In China, the strain method is usually used for load measurement, among which the load calibration test is the most critical link. Whether the calibration load is consistent or close to the actual load on the wing directly affects the accuracy of load measurement. Through years of technological development in China, the calibration test is carried out by applying multi-point vertical unidirectional loads to the lower wing of the aircraft. The measurement error of the wing bending moment and shear force can be basically controlled within 5%, meeting the load verification requirements; however, due to the small magnitude of the torque calibration load, severe coupling, and single direction when using this calibration test method, the torque load measurement error often exceeds 10%. It is only used as reference data during load verification. Therefore, the measurement of wing torque load has also become a difficult problem in the flight load measurement industry. At the same time, with the large-span flexible wings in China being widely used in military and civilian aircraft, the wing torque load is of great significance to the structural load verification and the aircraft rudder control characteristics. Therefore, there is an urgent need to study a method for high-precision measurement of wing torque load. Summary of the invention
[0003] The purpose of the present invention is to provide a method for measuring the torque of an aircraft wing with high precision, so as to directly perform a load calibration test on the aircraft wing in the original state, and solve the problem of measuring the torque load of the wing.
[0004] Technical solution:
[0005] A high-precision measurement method for aircraft wing torque, comprising:
[0006] Step 1: Arrange strain sensors on the torque load bearing path of the aircraft wing;
[0007] Step 2: Determine the airfoil torque calibration test conditions;
[0008] Step 3: Connect a single or multiple combined loading pads to the loading device at the lower wing surface loading point by bonding; perform tension / compression loading on the vertical wing surface through a hydraulic servo actuator, and establish a high-precision torque measurement load equation.
[0009] Furthermore, in step 1, the aircraft wing torque load bearing path includes a beam web, upper and lower skins, and strain sensors are bridge-arranged on the beam web and upper and lower skins in a temperature compensation manner to eliminate the influence of structural temperature on torque load measurement.
[0010] Furthermore, in step 2, the wing torque calibration test condition includes three aspects: torque calibration load size, type and quantity.
[0011] Furthermore, the torque calibration load of each section should not be less than 40% of the torque limit load of the section.
[0012] Furthermore, the types of calibrated load conditions include pure torque and shear-bending-torsion combination conditions in both leading edge downward and leading edge upward directions.
[0013] Furthermore, the wing torque calibration test conditions include modeling conditions and model verification conditions. The number of modeling conditions shall not be less than the number of torque bridges, and the model verification conditions shall at least include the maximum pure torque conditions in the two directions of leading edge downward and leading edge upward.
[0014] Furthermore, in step 3, the places where the local strength of the wing structure is relatively large are selected, including the intersection of the wing spar and the wing rib.
[0015] Furthermore, in step 3, in the case of two loading pads, the two loading pads are spliced and the central loading points of the two loading pads are connected through the same loading beam, and the wing load is loaded by applying a load to the loading beam.
[0016] Beneficial effects:
[0017] (1) The magnitude of the wing torque loading condition has increased significantly
[0018] By using adhesive multi-area wing loading pads, when the local strength of the wing is limited, the loading area is increased (double pads, four pads lever combination), which increases the torque calibration load by multiples compared with conventional loading methods, significantly improving the torque calibration load magnitude and solving the problem that conventional methods cannot achieve. Thus, the calibration load is not less than 40% of the torque limit load of the section.
[0019] (2) Rich torque load test conditions
[0020] Adhesive loading pads are used to apply tensile / compressive loads to the wing surface simultaneously, realizing torque load calibration test conditions such as large torque, positive and negative torque, and pure torque. The pure torque test condition is used for torque load model verification, which is conducive to the decoupling of bending moment, shear force, and torque loads.
[0021] (3) Reduced the load requirements of test restraint equipment
[0022] By applying tensile / compressive loads to the front and rear beams simultaneously, the vertical loads can offset themselves, which can reduce the restraint capacity requirements for the test restraint equipment compared to conventional methods.
[0023] (4) Solved the problem of poor measurement accuracy of wing torque
[0024] Under the condition that the local pressure on the wing surface remains unchanged, the torque measurement technology proposed in this paper has been applied in a certain type of aircraft. The wing surface torque measurement error has been improved from 20% to 7%, thus solving the problem of poor accuracy in measuring wing surface torque load in the past. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 Schematic diagram of the loading device;
[0026] Figure 2 (a) shows a single loading pad, Figure 2 (b) shows a combination of two loading pads, and Figure 2 (c) shows a combination of four loading pads;
[0027] Figure 3 Schematic diagram of loading position for wing torque load calibration;
[0028] Among them, there are a loading pad 1, a load sensor 2, a hydraulic actuator 3, a hinge support 4, a wing rib 5, a wing beam 6, a first load measuring section 7, a first load measuring section 8, and a reference torque axis 9. DETAILED DESCRIPTION
[0029] The present application provides a method for high-precision measurement of aircraft wing torque load. It mainly includes:
[0030] Step 1: Arrange strain sensors on the torque load bearing path of the aircraft wing;
[0031] Step 2: Design the wing torque calibration test conditions;
[0032] Step 3: Connect the loading pad 1 (single or multiple combinations) to the loading device at the lower wing surface loading point by bonding; perform tension / compression loading on the vertical wing surface through the hydraulic servo actuator, and establish a high-precision torque measurement load equation.
[0033] In step 1: the aircraft wing torque load bearing path includes a beam web, upper and lower skins, and strain sensors are bridge-arranged on the beam web and upper and lower skins respectively by using temperature compensation to eliminate the influence of structural temperature on torque load measurement.
[0034] Step 2, specifically: the wing torque calibration test condition includes three aspects: torque calibration load size, type and quantity.
[0035] Since the actual flight measurement of structural loads is generally carried out by measuring the concentrated loads outside the section according to different sections, the torque calibration load of each section should not be less than 40% of the torque limit load of the section; the types of wing torque calibration test conditions include pure torque in the leading edge downward and leading edge upward directions, and shear-bending-torsion combination conditions; the wing torque calibration test conditions include modeling conditions and model verification conditions. The number of modeling conditions shall not be less than the number of torque bridges, and the model verification conditions shall at least include the maximum pure torque conditions in the leading edge downward and leading edge upward directions.
[0036] In step 3, the lower wing surface loading point is generally selected where the local strength of the wing surface structure is relatively large, such as the intersection of the rib and the spar. Some aircraft structures adopt the structural form of upper and lower thick wall panels, and loading can also be performed on the wall panels. The location of the wing surface loading point and the size of the loading pad are determined according to the local strength limit of the wing surface structure and the calibration load size requirements.
[0037] The purpose of bonding the loading pad to the lower wing surface is to achieve tension and compression / bidirectional loading, and then to achieve loading of the torque calibration test condition. Compared with a single loading direction vertically upward, the torque can be doubled while the local strength and pad area conditions remain unchanged; the tension and compression bidirectional loading pads can be selected in a combination of one, two or four pieces (superimposed and combined in the form of a lever) according to the conditions of the test machine, so as to achieve the requirement that the calibration load is not less than 40% of the torque limit load of the section.
[0038] In the case of two loading pads, the two loading pads are spliced and the central loading points of the two loading pads are connected through the same loading beam, and the wing load is loaded by applying a load to the loading beam;
[0039] In the case of four loading pads, the four loading pads are spliced together and the central loading points of the four loading pads are connected in pairs through two loading beams respectively. The two beams are connected through another beam, and the wing load is loaded by applying a load to the other beam.
[0040] The high-precision torque measurement load equation is modeled using a shear-bending-torsion combined working condition, and the accuracy of the torque load measurement is tested through positive pure torque conditions and negative pure torque conditions to evaluate whether the flight test mission requirements for torque load measurement are met.
[0041] This embodiment provides a high-precision measurement method for aircraft wing torque load, which can be widely used for aircraft wing load measurement. The method includes the following contents:
[0042] According to the force transmission characteristics of the aircraft wing structure, torque load test strain gauge bridges are installed at beam webs, wing box skins and other locations, and bridges are assembled using temperature compensation technology to eliminate the influence of structural temperature on torque load measurement;
[0043] The principles to be followed when designing the torque load calibration test conditions are as follows: cover all force transmission paths of the wing structure, distribute the loading points as evenly as possible on the wing surface, the number of modeling conditions should not be less than the number of strain bridges of the load-testing section, and the calibration load should be greater than 40% of the section limit load. The load condition format is shown in Table 1.
[0044] Push the aircraft into the determined position and lift it up with a jack (just lift the wheels off the ground); use a level to level the aircraft front and back and left and right; fix and restrain the aircraft at the designated position in the test site according to the test outline design; the restraint bearing capacity of the restraint equipment should meet the support and balance requirements under all wing torque calibration loads.
[0045] Mark and measure the position of the wing surface loading point, and use the specially developed wing surface pad bonding process to glue and cure the adhesive loading pad; the combination of loading pads is shown in Figure 2(a) to Figure 2(c) .
[0046] Connect the load sensor 2, hydraulic actuator 3, hinge support 4, strain and load data acquisition equipment at the lower end of the loading pad; Figure 1 .
[0047] After all preparations for the test are in place, complete the test compliance check and start the calibration test according to the test outline.
[0048] The calibration load and structural strain bridge response data are obtained, and the relationship between torque load and strain, namely, the torque load equation, is established using the modeling condition data. The accuracy of the torque load measurement is tested through positive pure torque conditions and negative pure torque conditions to see if it meets the mission requirements, which is used for wing torque load measurement in actual flight.
[0049] The torque load condition should clearly specify the loading center position of each wing surface, the center coordinates of the loading area, the load magnitude, the load direction, the distance from the center of the loading area to the reference torque axis and the torque value of the load measurement section. The expression method is shown in Table 1.
[0050] Table 1 Torque calibration test load conditions
[0051]
[0052] The main load forms of the wing structure include shear force, bending moment and torque. When designing the working condition, comprehensive consideration should be given to improve the test efficiency. This embodiment only describes the working condition of the wing torque load, and takes the body coordinate system as the reference coordinate system, where X, Y, and Z represent the heading, lateral, and vertical coordinate values respectively; Taking the working condition GK-n as an example, L niIndicates the distance from the center point of the i-th loading area to the torque axis in the n-th working condition, F ni represents the operating condition value of the i-th loading area in the n-th operating condition, T n Indicates the total torque value of the nth working condition. See the distribution of loading points, load profile, and reference torque axis for details. Figure 3 .
Claims
1. A high-precision measurement method for aircraft wing torque, characterized in that: include: Step 1: Arrange strain sensors on the torque load bearing path of the aircraft wing; Step 2: Determine the airfoil torque calibration test conditions; Step 3: Connect a single or multiple combined loading pads to the loading device at the lower wing surface loading point by bonding; perform tension / compression loading on the vertical wing surface through a hydraulic servo actuator, and establish a high-precision torque measurement load equation.
2. The high-precision measurement method for aircraft wing torque according to claim 1, characterized in that: In step 1, the aircraft wing torque load bearing path includes the beam web, upper and lower skins, and strain sensors are arranged in a bridge manner on the beam web and upper and lower skins using temperature compensation to eliminate the influence of structural temperature on torque load measurement.
3. The high-precision measurement method for aircraft wing torque according to claim 2, characterized in that: In step 2, the wing torque calibration test condition includes three aspects: torque calibration load size, type and quantity.
4. The high-precision measurement method for aircraft wing torque according to claim 3, characterized in that: The torque calibration load of each section should not be less than 40% of the torque limit load of the section.
5. The high-precision measurement method for aircraft wing torque according to claim 1, characterized in that: The types of calibration load conditions include pure torque and shear-bending-torsion combination in both leading edge downward and leading edge upward directions.
6. The high-precision measurement method for aircraft wing torque according to claim 1, characterized in that: The wing torque calibration test conditions include modeling conditions and model verification conditions. The number of modeling conditions shall not be less than the number of torque bridges, and the model verification conditions shall at least include the maximum pure torque conditions in the two directions of leading edge downward and leading edge upward.
7. The high-precision measurement method for aircraft wing torque according to claim 1, characterized in that: In step 3, select the places where the wing structure has greater local strength, including the intersection of the wing spar and the rib.
8. The high-precision measurement method for aircraft wing torque according to claim 1, characterized in that: In step 3, in the case of two loading pads, the two loading pads are spliced and the central loading points of the two loading pads are connected through the same loading beam, and the wing load is loaded by applying a load to the loading beam.