Large continuous wind tunnel balance design strain quantification method

Abstract

The invention discloses a large continuous wind tunnel balance design strain quantification method, and belongs to the technical field of wind tunnel balance design. The problem that in the prior art, a traditional wind tunnel balance design strain method does not completely respond to the actual requirement of a wind tunnel test is solved. The method comprises the following steps: determining an integral repeatability characteristic quantity value t of each measurement Wheatstone bridge and a measurement and control acquisition device of the wind tunnel balance, and calculating to obtain a dynamic pressure q of a test section; calculating to obtain a resolution required value of each component of the wind tunnel balance in combination with a force measurement test precision index requirement of the model test; calculating the minimum design strain requirement of each component of the wind tunnel balance under the wind tunnel test precision index by combining the design load requirement of the wind tunnel balance; materials mechanics and a finite element analysis method are applied to design and determine a layout mode and size parameters of wind tunnel balance elements, and design strain requirements of each component of the wind tunnel balance are met. The method effectively quantifies the design strain requirements of each component of the wind tunnel balance, and can be applied to design of the wind tunnel balance.

Description

Technical Field

[0001] The invention relates to a large-scale continuous wind tunnel balance design strain quantification method, belonging to the technical field of wind tunnel balance design. Background Art

[0002] In the development and modification of large transport aircraft, passenger aircraft and other equipment models, the solution of many aerodynamic phenomena and engineering problems needs to rely on the experimental research of large continuous wind tunnels. Large continuous wind tunnels have technical advantages such as a wide range of Mach numbers and good flow field quality. However, the quality and performance of wind tunnels only represent the ability to reproduce the flight environment. The wind tunnel test multi-component aerodynamic measurement device-wind tunnel balance is the key factor in determining the high-precision / high-efficiency test of aerodynamics of large aircraft. For example, in the modification process of large aircraft, the performance of different rounds of schemes tends to converge, and the drag coefficient of wind tunnel tests is often within 0.0003. Therefore, the accuracy of the repeatable drag coefficient of high-speed wind tunnel tests in the same period needs to reach 0.00005, and the accuracy of the repeatable drag coefficient of different periods needs to reach 0.0001. Therefore, it is necessary to develop a high-precision wind tunnel balance.

[0003] Design strain is an important indicator of wind tunnel balance, which directly determines the test accuracy of wind tunnel balance. In the prior art, considering the bonding strength of strain gauge and the maximum combined stress limit allowed by the balance body material, a guideline for design strain of wind tunnel balance is proposed, that is, the design strain value range of high-speed wind tunnel balance is 150 -500 , the design strain range of the low-speed wind tunnel balance is 300 -1000 However, the above guidance suggestions are mainly based on the distinction between high-speed wind tunnels and low-speed wind tunnels, and a recommended range of design strain for the balance is given. The operation modes of the wind tunnel, i.e., transient, pulsed and continuous, are not considered, and the actual needs of wind tunnel tests are not fully responded to, and the development of equipment models such as large transport aircraft and passenger aircraft cannot be effectively supported.

[0004] In summary, a strain quantification method for large-scale continuous wind tunnel balance design that meets the needs of wind tunnel testing is needed. Summary of the invention

[0005] A brief overview of the present invention is provided below in order to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify key or important parts of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] In view of this, in order to solve the problem that the traditional wind tunnel balance design strain method in the prior art does not fully respond to the actual needs of wind tunnel tests, the present invention provides a large-scale continuous wind tunnel balance design strain quantification method.

[0007] The technical solution is as follows: A large-scale continuous wind tunnel balance design strain quantification method includes the following steps: S1. Arrange the repeatability test data of the completed large-scale continuous test, and determine the overall repeatability characteristic value t of each measurement Wheatstone bridge and measurement and control acquisition device of the wind tunnel balance; S2. Design a wind tunnel balance, collect test requirements and test model parameters of the test section model area of ​​the model test, and calculate the dynamic pressure q of the test section; S3. According to the test requirements of the test section model area and the test section dynamic pressure q, combined with the force test accuracy requirements of the model test, calculate the required resolution values ​​of each component of the wind tunnel balance; Specifically: The components of the wind tunnel balance include normal force, pitch moment, roll moment, axial force, lateral force, and yaw moment; S4. According to the resolution requirement value of each component of the wind tunnel balance and the overall repeatability characteristic value t, combined with the design load requirement of the wind tunnel balance, the minimum design strain requirement of each component of the wind tunnel balance under the wind tunnel test accuracy index is calculated and integrated into the design strain requirement of each component of the balance; S5. Apply material mechanics and finite element analysis methods to design and determine the layout and size parameters of wind tunnel balance components to meet the design strain requirements of each component of the wind tunnel balance.

[0008] Furthermore, in S2, the Mach number M and the front chamber total pressure of the test section model area of ​​the model test are collected. The test requirements and test model parameters, namely the reference area s, the average aerodynamic chord length of the wing and the wing span L, the dynamic pressure q of the test section is calculated; The dynamic pressure q of the test section is expressed as: ; in, is the static pressure of the test section model area, .

[0009] Furthermore, in S3, the resolution requirement value of the normal force is It is expressed as: ; Resolution requirement of pitch moment It is expressed as: ; Resolution requirement of rolling moment It is expressed as: ; Resolution requirement of axial force It is expressed as: ; Resolution requirement for lateral force It is expressed as: ; Required resolution of yaw moment It is expressed as: ; in, is the accuracy requirement value of the normal force coefficient, is the required value of the pitch moment coefficient accuracy index, is the required value of the rolling moment coefficient, is the accuracy index requirement value of the axial force coefficient, is the accuracy index requirement value of the lateral force coefficient, It is the accuracy requirement value of the yaw moment coefficient.

[0010] Furthermore, in S3, the minimum design strain requirement for the normal force is It is expressed as: ; Minimum design strain requirement for pitching moment It is expressed as: ; Minimum design strain requirements for rolling moment It is expressed as: ; Minimum design strain requirement for axial force It is expressed as: ; Minimum design strain requirements for lateral forces It is expressed as: ; Minimum design strain requirement for yaw moment It is expressed as: ; in, is the design load requirement for the normal force, is the design load requirement for the pitching moment, is the design load requirement for the rolling moment, is the design load requirement for the axial force, is the design load requirement for the lateral force, is the design load requirement for the yaw moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the normal force, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the pitching moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the rolling moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring axial force, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring lateral forces, Sensitivity of the strain gauge used in the Wheatstone bridge for the measurement of yaw moment.

[0011] The beneficial effects of the present invention are as follows: a large-scale continuous wind tunnel balance design strain quantification method provided by the present invention carefully combs and analyzes the repeatability test data in previous large-scale continuous tests, and accurately obtains the overall repeatability characteristic value of the wind tunnel balance test system; the present invention fully responds to the actual needs of wind tunnel tests, accurately quantifies the design strain requirements of each component of the balance corresponding to the wind tunnel test accuracy index, and effectively supports the development of equipment models such as large transport aircraft and passenger aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 Schematic diagram of the process for designing a strain quantification method for a large continuous wind tunnel balance; Figure 2 Schematic diagram of the structure of a wind tunnel balance with a diameter of 50 mm. DETAILED DESCRIPTION

[0013] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0014] refer to Figure 1-Figure 2 The present embodiment is described in detail, a large-scale continuous wind tunnel balance design strain quantification method comprises the following steps: S1. Arrange the repeatability test data of the completed large-scale continuous test, and determine the overall repeatability characteristic value t of each measuring Wheatstone bridge and measurement and control acquisition device of the wind tunnel balance, t=0.5, in units of ; S2. Design a wind tunnel balance, collect test requirements and test model parameters of the test section model area of ​​the model test, and calculate the dynamic pressure q of the test section; S3. According to the test requirements of the test section model area and the test section dynamic pressure q, combined with the force test accuracy requirements of the model test, calculate the required resolution values ​​of each component of the wind tunnel balance; Specifically: The components of the wind tunnel balance include normal force, pitch moment, roll moment, axial force, lateral force, and yaw moment; S4. According to the resolution requirement value of each component of the wind tunnel balance and the overall repeatability characteristic value t, combined with the design load requirement of the wind tunnel balance, the minimum design strain requirement of each component of the wind tunnel balance under the wind tunnel test accuracy index is calculated and integrated into the design strain requirement of each component of the balance; S5. Apply material mechanics and finite element analysis methods to design and determine the layout and size parameters of wind tunnel balance components to meet the design strain requirements of each component of the wind tunnel balance.

[0015] Furthermore, in S2, the Mach number M and the front chamber total pressure of the test section model area of ​​the model test are collected. The test requirements and test model parameters, namely the reference area s, the average aerodynamic chord length of the wing and the wing span L, the dynamic pressure q of the test section is calculated; The dynamic pressure q of the test section is expressed as: ; in, is the static pressure of the test section model area, .

[0016] Furthermore, in S3, the resolution requirement value of the normal force is It is expressed as: ; Resolution requirement of pitch moment It is expressed as: ; Resolution requirement of rolling moment It is expressed as: ; Resolution requirement of axial force It is expressed as: ; Resolution requirement for lateral force It is expressed as: ; Required resolution of yaw moment It is expressed as: ; in, is the accuracy requirement value of the normal force coefficient, is the required value of the pitch moment coefficient accuracy index, is the required value of the rolling moment coefficient, is the accuracy index requirement value of the axial force coefficient, is the accuracy index requirement value of the lateral force coefficient, is the accuracy requirement value of the yaw moment coefficient; Specifically, in this embodiment, M=1.4, =104000, unit is Pa, s=0.2391814, unit is , =0.259, unit is m, L=1.142857, unit is m, q=44838.4, unit is Pa, =0.001, =0.0004, =0.00006, =0.00016, =0.0004, =0.0001, =10.72, unit is N, =1.11, unit is Nm, =0.74, unit is Nm, =1.72, unit is N, =4.28, unit is N, =1.23, unit is Nm.

[0017] Furthermore, in S3, the minimum design strain requirement for the normal force is It is expressed as: ; Minimum design strain requirement for pitching moment It is expressed as: ; Minimum design strain requirements for rolling moment It is expressed as: ; Minimum design strain requirement for axial force It is expressed as: ; Minimum design strain requirements for lateral forces It is expressed as: ; Minimum design strain requirement for yaw moment It is expressed as: ; in, is the design load requirement for the normal force, is the design load requirement for the pitching moment, is the design load requirement for the rolling moment, is the design load requirement for the axial force, is the design load requirement for the lateral force, is the design load requirement for the yaw moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the normal force, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the pitching moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the rolling moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring axial force, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring lateral forces, The sensitivity of the strain gauges used in the Wheatstone bridge for the measurement of yaw moment; Specifically, =15000, =800, =700, =1200, =5000, =400; Since the strain gauges used to measure the Wheatstone bridge in each component of the wind tunnel balance are the same, =2, =2, =2, =2, =2, =2; The minimum design strain requirements of each component of the wind tunnel balance are calculated, and the units are , =349.7, =180, =238, =174.8, =236.3, =81.6; refer to Figure 2, considering the size and space of the wind tunnel balance installed inside the aircraft model, the diameter of the wind tunnel balance is determined to be 50, in mm, the measuring elements of normal force, pitch moment, rolling moment, lateral force and yaw moment are rectangular beams, and the axial force element is a "T" beam. The shape and measuring elements of the wind tunnel balance are designed by applying material mechanics and finite element analysis methods. Among them, the distance between the rectangular beams is L=140mm, the length of the rectangular beam is L1=15mm, the width of the rectangular beam is b1=23.5mm, and the height of the rectangular beam is h1=38 mm, support beam height L2=22mm, support beam width b2=13mm, support beam thickness h2=1.5mm, "T" beam measurement beam height L3=11mm, "T" beam measurement beam long side width b3=10mm, "T" beam measurement beam short side width b4=3mm, "T" beam measurement beam thickness h3=3.4mm, "T" beam cross beam thickness h4=0.7mm, "T" beam cross beam length L4=33mm, the normal force design strain is 945, the unit is , the pitching moment design strain is 722, in units of , the rolling moment design strain is 669, in units of , the axial force design strain is 617, the unit is , the lateral force design strain is 470 and the yaw moment design strain is 559 in units of , which fully meets and is greater than the minimum design strain requirement obtained.

[0018] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

Claims

1. A large-scale continuous wind tunnel balance design strain quantification method, characterized in that: The following steps are involved: S1. Arrange the repeatability test data of the completed large-scale continuous test, and determine the overall repeatability characteristic value t of each measurement Wheatstone bridge and measurement and control acquisition device of the wind tunnel balance; S2. Design a wind tunnel balance, collect test requirements and test model parameters of the test section model area of ​​the model test, and calculate the dynamic pressure q of the test section; S3. According to the test requirements of the test section model area and the test section dynamic pressure q, combined with the force test accuracy requirements of the model test, calculate the required resolution values ​​of each component of the wind tunnel balance; Specifically: The components of the wind tunnel balance include normal force, pitch moment, roll moment, axial force, lateral force, and yaw moment; S4. According to the resolution requirement value of each component of the wind tunnel balance and the overall repeatability characteristic value t, combined with the design load requirement of the wind tunnel balance, the minimum design strain requirement of each component of the wind tunnel balance under the wind tunnel test accuracy index is calculated and integrated into the design strain requirement of each component of the balance; S5. Apply material mechanics and finite element analysis methods to design and determine the layout and size parameters of wind tunnel balance components to meet the design strain requirements of each component of the wind tunnel balance.

2. The large-scale continuous wind tunnel balance design strain quantification method according to claim 1 is characterized in that: In S2, the Mach number M and the total pressure of the front chamber of the test section model area of ​​the model test are collected. The test requirements and test model parameters, namely the reference area s, the average aerodynamic chord length of the wing and the wing span L, the dynamic pressure q of the test section is calculated; The dynamic pressure q of the test section is expressed as: ； in, is the static pressure of the test section model area, .

3. The large-scale continuous wind tunnel balance design strain quantification method according to claim 2, characterized in that: In S3, the resolution requirement of the normal force is It is expressed as: ； Resolution requirement of pitch moment It is expressed as: ； Resolution requirement of rolling moment It is expressed as: ； Resolution requirement of axial force It is expressed as: ； Resolution requirement for lateral force It is expressed as: ； Required resolution of yaw moment It is expressed as: ； in, is the accuracy index requirement value of the normal force coefficient, is the required value of the pitch moment coefficient accuracy index, is the required value of the rolling moment coefficient, is the accuracy index requirement value of the axial force coefficient, is the accuracy index requirement value of the lateral force coefficient, It is the accuracy requirement value of the yaw moment coefficient.

4. A large-scale continuous wind tunnel balance design strain quantification method according to claim 3, characterized in that: In S3, the minimum design strain requirement for normal force It is expressed as: ； Minimum design strain requirement for pitching moment It is expressed as: ； Minimum design strain requirements for rolling moment It is expressed as: ； Minimum design strain requirement for axial force It is expressed as: ； Minimum design strain requirements for lateral forces It is expressed as: ； Minimum design strain requirement for yaw moment It is expressed as: ； in, is the design load requirement for the normal force, is the design load requirement for the pitching moment, is the design load requirement for the rolling moment, is the design load requirement for the axial force, is the design load requirement for the lateral force, is the design load requirement for the yaw moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the normal force, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the pitching moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring the rolling moment, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring axial force, The sensitivity of the strain gauge used in the Wheatstone bridge for measuring lateral forces, Sensitivity of the strain gauge used in the Wheatstone bridge for the measurement of yaw moment.

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