CN115743595A - Large-strain test flight test method for helicopter flexible part - Google Patents
Large-strain test flight test method for helicopter flexible part Download PDFInfo
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- CN115743595A CN115743595A CN202211495504.6A CN202211495504A CN115743595A CN 115743595 A CN115743595 A CN 115743595A CN 202211495504 A CN202211495504 A CN 202211495504A CN 115743595 A CN115743595 A CN 115743595A
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Abstract
The invention discloses a large-strain test flight testing method for a flexible part of a helicopter, wherein a damping pad made of a specific material and having a specific thickness is adhered to the strain measuring position of the flexible part, a strain gauge M1 is adhered to the damping pad, and a strain gauge M2 is directly adhered to the position close to the strain measuring position. The method comprises the following steps of carrying out comparison test on two strain signals through a ground bench test and a flight test, selecting a proper damping pad material and thickness, obtaining a damping coefficient of a damping pad, and obtaining a true strain value of a flexible component through a strain gauge signal and the damping coefficient on the damping pad in the test flight process of the helicopter. By adopting the testing method provided by the invention, the problem of short service life of the test strain gauge for testing the test flight of the flexible part of the helicopter is effectively solved, and the service life of the strain gauge is obviously prolonged; and providing a real load test of the flexible part for a flight test.
Description
Technical Field
The invention belongs to the technical field of test flight tests of helicopters, and particularly relates to a large-strain test flight test method for a flexible part of a helicopter.
Background
The flexible parts of the helicopter mainly refer to a main-rotor flexible beam and a tail-rotor flexible beam. The flexible beam plays a role in connecting the blade and the hub, the blade variable pitch is generated by deformation of the flexible beam, and the strain of the flexible beam is a key parameter for the flexibility Liang Dingshou and the test flight safety of the helicopter. In the test flight process of the helicopter, the flexibility Liang Chengshou has large deformation amount through the aerodynamic load and the pitch variation of the blades, and the height Zhou Yingbian of more than +/-5000 mu epsilon can be generated. The measurement range of the conventional strain gauge can reach 108 cycle lives within +/-1200 mu epsilon, and the cycle number of the strain gauge is obviously reduced under a high-strain working environment. The service life of the flexible part strain gauge is only dozens of minutes to one or two hours in the test flight process, the rotor system needs to be repeatedly disassembled and assembled to repair the flexible beam strain gauge, and the implementation of the test flight task of the helicopter is seriously influenced.
Disclosure of Invention
The purpose of the invention is as follows: the invention provides a large-strain test flight testing method for a helicopter flexible part, which aims to effectively prolong the service life of a rotor system for a flexible beam strain gauge.
The technical scheme is as follows: a large strain test flight test method for a flexible component of a helicopter is characterized in that a damping pad made of a specific material and having a specific thickness is pasted at a strain measurement position of the flexible component, a first strain gauge is pasted on the damping pad, and a second strain gauge is directly pasted at a position close to the strain measurement position; the method comprises the following steps of carrying out comparison test on two strain signals through a ground bench test and a flight test, determining a proper damping pad material and thickness, obtaining a damping coefficient of a damping pad, and obtaining a true strain value of a flexible component through strain gauge signal output and the damping coefficient on the damping pad in the test flight process of the helicopter.
The invention discloses a large-strain test flight testing method for a helicopter flexible part, which comprises the following steps of:
firstly, a damping pad made of a specific material and having a specific thickness is stuck to a strain measurement position of the flexible part, a first strain gauge (M1) is stuck to the damping pad, the elastic modulus of the damping pad is not more than 1/50 of the elastic modulus of the flexible part, and the thickness of the damping pad is not more than 1/3 of the thickness of the flexible part;
directly sticking a second strain gauge (M2) to the position, close to the strain measurement position, of the flexible part for comparison test;
step three, using a ground test bed to dynamically load according to main working frequency points of the flexible part, wherein the loading load is about 60 percent of the actual working load, and respectively measuring the strain output epsilon of the strain gauges M1 and M2 1 、ε 2 Obtaining a damping coefficient K 1 ＝ε 2 /ε 1 ；
Step four, the flexible partThe estimated maximum deformation of the measured position is xi (mu epsilon), and xi/K is calculated 1 The value of. If 300 mu epsilon is less than or equal to xi/K 1 Less than or equal to 1200 mu epsilon, entering the next step, if xi/K 1 > 1200 mu epsilon or xi/K 1 If the diameter is less than 300 mu epsilon, the step I is carried out again, and the material and the thickness of the damping pad are adjusted;
step five, installing the flexible component, carrying out ground driving and flight detection on the helicopter, and respectively measuring strain output epsilon of the strain gauges M1 and M2 3 、ε 4 To obtain the real damping coefficient K of the test flight 2 ＝ε 4 /ε 3 Calculating xi/K 2 The value of the sum of the values,.1. The. If 300 mu epsilon is less than or equal to xi/K 2 Less than or equal to 1200 mu epsilon, entering the next step, if xi/K 2 > 1200 mu epsilon or xi/K 2 If the diameter is less than 300 mu epsilon, the step I is carried out again, and the material and the thickness of the damping pad are adjusted;
sixthly, carrying out a flight test by the helicopter, and measuring the strain output of the strain gauge M1 as epsilon 5 The actual strain of the flexible part can be obtained as K 2 *ε 5 。
Further, in the fourth step, the specific adjustment method is as follows: if xi/K 1 More than 1200 mu epsilon, selecting a damping pad material with smaller elastic modulus or increasing the thickness of the damping pad; if xi/K 1 If the elastic modulus is less than 300 mu epsilon, selecting a damping pad material with larger elastic modulus or reducing the thickness of the damping pad;
compared with the prior art, the invention has the following positive effects: the problem that the service life of the strain gauge for the test flight of the flexible part of the helicopter is short is solved, and the real load test of the flexible part is provided for the flight test; the concrete expression is as follows:
1. the service life of the strain gauge is remarkably prolonged, and the effective service life of the strain gauge in the actual flying process can reach more than dozens of hours through implementation verification;
2. the method is compatible with the original acquisition equipment, and the rear-end acquisition equipment does not need to be changed;
3. a larger strain signal can be measured.
Drawings
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic view of the adhesion of strain gauges M1 and M2.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, a damping pad made of a specific material and having a specific thickness is adhered to a strain measurement position of a flexible component, one strain gauge is adhered to the damping pad, and the other strain gauge is directly adhered to a position close to the strain measurement position; the method comprises the following steps of carrying out comparison test on two strain signals through a ground bench test and a flight test, determining a proper damping pad material and thickness, obtaining a damping coefficient of a damping pad, and obtaining a true strain value of a flexible component through strain gauge signal output and the damping coefficient on the damping pad in the test flight process of the helicopter. The specific implementation process comprises the following steps:
(1) Pasting a damping pad made of a specific material and with a specific thickness at the strain measurement position of the flexible part, pasting a first strain gauge M1 on the damping pad, wherein the elastic modulus of the damping pad is not more than 1/50 of the elastic modulus of the flexible part, and the thickness of the damping pad is not more than 1/3 of the thickness of the flexible part;
(2) Directly sticking a second strain gauge M2 to the position, close to the strain measurement, of the flexible part for comparison test;
(3) Dynamically loading the main working frequency points of the flexible parts by using a ground test bed, wherein the loading load is about 60 percent of the actual working load, and respectively measuring the strain output epsilon of the strain gauges M1 and M2 1 、ε 2 Obtaining a damping coefficient K 1 ＝ε 2 /ε 1 ；
(4) The estimated maximum deformation of the measured position of the flexible part is xi (mu epsilon), and xi/K is calculated 1 Value, if 300 mu epsilon is less than or equal to xi/K 1 Less than or equal to 1200 mu epsilon, entering the next step, if xi/K 1 > 1200 mu epsilon or xi/K 1 ＜
300 mu epsilon, and the step I is carried out again to adjust the material and the thickness of the damping pad. The specific adjusting method comprises the following steps:
if xi/K 1 More than 1200 mu epsilon, selecting a damping pad material with smaller elastic modulus or increasing the thickness of the damping pad, if xi/K 1 If the elastic modulus is less than 300 mu epsilon, selecting a damping pad material with larger elastic modulus or reducing the thickness of the damping pad;
(5) The flexible part is installed, the helicopter is driven on the ground and flies, and the strain output epsilon of the strain gauges M1 and M2 is respectively measured 3 、ε 4 To obtain the real damping coefficient K of the test flight 2 ＝ε 4 /ε 3 Calculating xi/K 2 A value; if 300 mu epsilon is less than or equal to xi/K 2 Less than or equal to 1200 mu epsilon, entering the next step, if xi/K 2 > 1200 mu epsilon or xi/K 2
If the diameter is less than 300 mu epsilon, the step I is carried out again, and the material and the thickness of the damping pad are adjusted;
(6) Carrying out flight test on the helicopter, and measuring the strain output of the strain gauge M1 as epsilon 5 The actual strain of the flexible part can be obtained as K 2 *ε 5 。
In the practical implementation process, when the material and the thickness of the damping pad are adjusted, the material selection is determined according to the deviation value, and the thickness can be adjusted by adopting a certain gradient; so that the test time can be shortened. Of course, the measuring method proposed by the present invention may be loaded in the form of a computer program in a memory of a computer, the computer comprising a processor and the memory, the computer program, when executed by the processor, implementing the procedures of the measuring method. In addition, the measurement method is loaded in a computer-readable storage medium in the form of a computer program, which when executed by a processor implements the procedures of the method. By adopting the testing method provided by the invention, the problem of short service life of the test strain gauge for testing the test flight of the flexible part of the helicopter is effectively solved, and the service life of the strain gauge is obviously prolonged; and providing a real load test of the flexible part for a flight test.
The foregoing is merely a detailed description of the embodiments of the present invention, and some of the conventional techniques are not detailed. The scope of the present invention is not limited thereto, and any changes or substitutions that can be easily made by those skilled in the art within the technical scope of the present invention will be covered by the scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. A test method for large strain test flight of a flexible component of a helicopter is characterized in that a damping pad made of a specific material and having a specific thickness is pasted at a strain measurement position of the flexible component, a first strain gauge is pasted on the damping pad, and a second strain gauge is directly pasted at a position close to the strain measurement position; the method comprises the following steps of carrying out comparison test on two strain signals through a ground bench test and a flight test, determining a proper damping pad material and thickness, obtaining a damping coefficient of a damping pad, and obtaining a true strain value of a flexible component through strain gauge signal output and the damping coefficient on the damping pad in the test flight process of the helicopter.
2. The helicopter flexible component large strain test flight test method of claim 1, characterized by the test method comprising the steps of:
step S1, pasting a damping pad made of a specific material and with a specific thickness at a strain measurement position of a flexible part, and pasting a first strain gauge (M1) on the damping pad;
s2, directly sticking a second strain gauge (M2) to the position, close to the strain measurement, of the flexible part for comparison test;
s3, dynamically loading according to main working frequency points of the flexible part by using a ground test bed, and respectively measuring strain outputs epsilon 1 and epsilon 2 of the strain gauges M1 and M2 to obtain a damping coefficient K1= epsilon 2/epsilon 1;
s4, calculating a xi/K1 value, wherein the estimated maximum deformation of the detected position of the flexible component is xi; if 300 mu epsilon is less than or equal to xi/K1 is less than or equal to 1200 mu epsilon, the step S5 is entered; if xi/K1 is more than 1200 mu epsilon or xi/K1 is less than 300 mu epsilon, the step S1 is carried out again, and the material and the thickness of the damping pad are adjusted;
s5, installing a flexible component, wherein the helicopter is driven on the ground and flies for detection, strain outputs epsilon 3 and epsilon 4 of the strain gauges M1 and M2 are respectively measured, a real damping coefficient K2= epsilon 4/epsilon 3 of the test flight is obtained, and a xi/K2 value is calculated; if 300 mu epsilon is less than or equal to xi/K2 is less than or equal to 1200 mu epsilon, the step S6 is carried out; if xi/K2 is more than 1200 mu epsilon or xi/K2 is less than 300 mu epsilon, the step S1 is carried out again, and the material and the thickness of the damping pad are adjusted;
and S6, carrying out a flight test by the helicopter, measuring the strain output of the strain gauge M1 to be epsilon 5, and obtaining the actual strain quantity of the flexible component to be K2. Epsilon.5.
3. The helicopter flexible part large strain test flight test method of claim 1, characterized in that when a damping pad of a specific material and thickness is pasted, the elastic modulus of the damping pad is not more than 1/50 of the elastic modulus of the flexible part, and the thickness is not more than 1/3 of the thickness of the flexible part itself.
4. The helicopter flexible part large strain test flight testing method according to claim 1, characterized in that the specific adjusting method in step S4 is: if xi/K1 is more than 1200 mu epsilon, a damping pad material with smaller elastic modulus is selected or the thickness of the damping pad is increased.
5. The test method for testing the large-strain test flight of the flexible part of the helicopter as claimed in claim 4, characterized in that in step S4, if ξ/K1 is less than 300 μ ε, the damping pad material with larger elastic modulus is selected or the thickness of the damping pad is reduced.
6. A helicopter flexible part large strain test flight test method according to claim 4 or 5, characterized in that when the thickness of the damping pad is increased or decreased, a certain gradient adjustment is adopted.
7. The method for testing large-strain test flight of a helicopter flexible component according to claim 1, characterized in that in step S3, the loading load is about 60% of the actual working load.
8. A helicopter flexible part large strain test flight testing method as claimed in claim 1, characterized in that said measuring method is loaded in the form of a computer program in the memory of a computer, said computer comprising a processor and said memory, the computer program when executed by the processor implements the procedure of said measuring method.
9. A helicopter flexible part large strain test flight testing method as claimed in claim 1, characterized in that said measurement method is loaded in a computer readable storage medium in the form of a computer program which, when executed by a processor, implements the procedure of said method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211495504.6A CN115743595A (en) | 2022-11-27 | 2022-11-27 | Large-strain test flight test method for helicopter flexible part |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211495504.6A CN115743595A (en) | 2022-11-27 | 2022-11-27 | Large-strain test flight test method for helicopter flexible part |
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| CN115743595A true CN115743595A (en) | 2023-03-07 |
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| CN202211495504.6A Pending CN115743595A (en) | 2022-11-27 | 2022-11-27 | Large-strain test flight test method for helicopter flexible part |
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