CN112414932A - Evaluation method for sand erosion resistance of protective material of helicopter rotor blade - Google Patents
Evaluation method for sand erosion resistance of protective material of helicopter rotor blade Download PDFInfo
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- CN112414932A CN112414932A CN202011326433.8A CN202011326433A CN112414932A CN 112414932 A CN112414932 A CN 112414932A CN 202011326433 A CN202011326433 A CN 202011326433A CN 112414932 A CN112414932 A CN 112414932A
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Abstract
The invention belongs to the technical field of application and management of helicopter materials, and particularly relates to a method for evaluating sand erosion resistance of a helicopter rotor blade protective material. The method specifically comprises the following steps: s1: manufacturing a rotor blade protective material test piece (100); s2: designing a test device (200) and installing the test piece (100); s3: determining a test parameter matrix, wherein the test parameters comprise a sand blowing angle, a sand blowing speed, a sand type and a test temperature; s4: performing a test according to the test parameter matrix determined in the step S3; s5: and (4) evaluating test results. The method can be used for checking the sand erosion resistance of the helicopter rotor blade protective material in the flight state, realizes the effect which cannot be achieved by the conventional method at present, and the checking result can carry out important support on the prediction of the actual service life of the blade protective material, thereby filling the domestic blank.
Description
Technical Field
The invention belongs to the technical field of application and management of helicopter materials, and particularly relates to a method for evaluating sand erosion resistance of a helicopter rotor blade protective material.
Background
Military helicopters are frequently in service in low-altitude, heavy-rain fields and unpaved-surface runways (environments with sand and dust clouds). The beating of sand, dust, etc. on the rotor blade composite surface can easily lead to fiber fracture or interface delamination in the composite, leading to premature failure of the structure. The sand erosion resistance protection of the helicopter blades is carried out by adopting various modes at home and abroad, the front edges of the blades are coated with metal materials such as iron alloy, titanium alloy, nickel alloy and the like, and the front edges of the blades are protected by adopting non-metals such as polyurethane, polycarbonate and the like or directly spraying protective coating on the blades, so that the sand erosion resistance performance of the protective materials can be checked in advance, the design efficiency of the protective materials can be obviously improved, and the protection and replacement cost can be reduced.
At present, similar inventions or documents are rarely reported, the protective material of the rotor blade of the helicopter is generally paved on the surface of the front edge of the rotor blade, and the tangential speed at the rotating blade tip of the rotor is generally about 200m/s when the helicopter is in service. The protective material coated with the excellent composite material front edge is selected, and the sand erosion resistance of the protective material is examined, so that the sand erosion resistance of the protective material in the actual service process can be effectively evaluated, the service life of the protective material can be evaluated, and the use risk and the maintenance cost can be reduced.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the defects of the existing assessment method, the invention designs a test matrix which is attached to the actual service state according to the environmental characteristics of the helicopter, designs a plurality of sand blowing angles, a plurality of sand blowing speeds, two sand types and a plurality of environmental temperatures to perform laboratory assessment on the protective material, provides the method for evaluating the sand erosion resistance of the protective material of the rotor blade of the helicopter, and fills the domestic blank.
The technical scheme of the invention is as follows: in order to achieve the purpose, the invention provides a method for evaluating the sand erosion resistance of a protective material of a helicopter rotor blade, which is characterized by comprising the following steps:
s1: manufacturing a rotor blade protective material test piece 100;
s2: designing a test device 200, and mounting the test piece 100; the test apparatus 200 includes a test stand 210, a feed chamber 220, a mixing chamber 230, a plenum 240, a pellet chamber 250, an environmental test chamber 300; the test bed 210 is used for placing the test piece 100, and a motor is mounted on the test bed 210 and can rotate for a certain angle along the horizontal direction; the feeding chamber 220 is located right above the test bed 210, the feeding chamber 220 is communicated with the mixing chamber 230, the granule chamber 250 and the gas feeding chamber 240 respectively feed sand granules and gas into the mixing chamber 230, and after the sand granules and the gas are mixed by the mixing chamber 230, sand is blown to the test piece 100 through a quartz nozzle 221 of the feeding chamber 220;
s3: determining a test parameter matrix, wherein the test parameters comprise a sand blowing angle, a sand blowing speed, a sand type and a test temperature;
the sand blowing angle refers to an action angle when the sand collides with the test piece;
the sand blowing speed refers to the speed of sand acting on the surface of the test piece;
the type of the sand refers to the type of the sand, and has the characteristics of special size and shape;
test temperature test ambient temperature, referred to herein as the temperature of the sand;
s4: performing a test according to the test parameter matrix determined in the step S3;
s5: and (4) evaluating test results.
In one possible embodiment, in the step S1, the test piece 100 is a sheet-like test piece.
In a possible embodiment, in step S3, the sand blowing angle is adjusted by adjusting the angle between the test bed 210 and the horizontal plane according to the angle of the collision between the helicopter rotor blade and sand in the rotating state, and the sand blowing angle is selected from one or more of 30 °, 45 °, 60 ° and 90 °.
In a possible embodiment, in step S3, the relative linear velocity of the blade leading edge is calculated according to the rotation speed of the rotor during the service of the blade of the helicopter and the length of the blade, and the sand blowing speed is selected from one or more of 30m/S, 80m/S, 130m/S, 180m/S and 220 m/S.
In one possible embodiment, in step S3, one or more sand of two size distributions is selected according to the types of sand in China and the world: a. imitating sand in Afu region: the size distribution is 45-250 μm, and the size less than 100 μm accounts for 75%; b. common quartz sand: 0-149 μm is about 5%, 149-600 μm is about 90%; more than 5 percent of more than 600 mu m.
In a possible embodiment, in the step S3, the higher the temperature is, the more remarkable the sand erosion phenomenon is, and the 5 ℃, 25 ℃, 50 ℃ are selected for the assessment test according to the global climate state.
In one possible embodiment, in the step S4, 3 or more test pieces are selected for parallel testing under each of the test conditions of sand blowing angle, sand blowing speed, sand type and test temperature.
In one possible embodiment, in the step S5, the rating of the eroded pit is performed according to the width and depth of the eroded pit on the surface of the test piece (100).
The invention designs the assessment test matrix of the protective material at the front edge of the blade according to the environmental conditions of the actual service state of the helicopter rotor blade, can be used for assessing the sand erosion performance of the protective material of the rotor blade in a flight state, and can achieve the effect which cannot be achieved by the existing method.
1) Designing the sand blowing speed in the interval of 30-220 m/s, covering the relative linear speed from the root to the front edge of the blade tip when the helicopter flies;
2) four sand blowing action angles of 30 degrees, 45 degrees, 60 degrees and 90 degrees are designed, and the angle at which sand and the blade interact most seriously is checked;
3) two kinds of quartz sand are designed: quartz sand in sandstone environment areas with severe sand global conditions and common areas in the simulated Afghanistan battlefield area is examined;
4) the possible service typical environment temperature of the helicopter at 5 ℃, 25 ℃ and 50 ℃ is designed for examination.
The invention has the beneficial effects that: the invention provides an evaluation method for evaluating the sand erosion resistance of a protective material of a helicopter rotor blade, which is characterized in that a test matrix is designed to evaluate the sand erosion resistance of the protective material based on the actual service state of the helicopter rotor blade, and the invention can be used for evaluating the sand erosion resistance of the protective material of the helicopter rotor blade in a flight state based on the comprehensive and representative evaluation conditions of different sand blowing angles, sand blowing speeds, test environment temperatures, sand types and the like, thereby realizing the effect which cannot be achieved by the conventional method at present, realizing the important support of the actual service life prediction of the blade protective material by the evaluation result and filling the domestic blank.
Drawings
FIG. 1 is a schematic view of the structure of the testing device 200 of the present invention
FIG. 2 is a flow chart of the method of the present invention
Wherein:
100-test piece; 200-test apparatus; 210-a test rig; 220-a feeding chamber; 230-a mixing chamber; 240-an air plenum; 250-a pellet chamber; 221-a quartz nozzle;
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the flowchart of the method 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 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.
As shown in fig. 2, a method for evaluating the sand erosion resistance of a protective material for a helicopter rotor blade is characterized by comprising the following steps:
s1: manufacturing a rotor blade protective material test piece 100; in the step S1, the test piece 100 is a sheet-like test piece;
s2: designing a test device 200, and mounting the test piece 100; as shown in fig. 1, the test apparatus 200 includes a test stand 210, a feeding chamber 220, a mixing chamber 230, a gas supply chamber 240, a pellet chamber 250, an environmental test chamber 300; the test bed 210 is used for placing the test piece 100, and a motor is mounted on the test bed 210 and can rotate for a certain angle along the horizontal direction; the feeding chamber 220 is located right above the test bed 210, the feeding chamber 220 is communicated with the mixing chamber 230, the granule chamber 250 and the gas feeding chamber 240 respectively feed sand granules and gas into the mixing chamber 230, and after the sand granules and the gas are mixed by the mixing chamber 230, sand is blown to the test piece 100 through a quartz nozzle 221 of the feeding chamber 220; the environmental test chamber 300 is used for adjusting the set environmental temperature;
s3: determining a test parameter matrix, wherein the test parameters comprise a sand blowing angle, a sand blowing speed, a sand type and a test temperature;
the sand blowing angle refers to an action angle when the sand collides with the test piece;
the sand blowing speed refers to the speed of sand acting on the surface of the test piece;
the type of the sand refers to the type of the sand, and has the characteristics of special size and shape;
test temperature the test ambient temperature, in this experiment, refers to the temperature of the sand;
as shown in table 1, according to the tilting angle of the helicopter rotor blade in a rotating state, the sand blowing angle is adjusted by adjusting the angle between the test bed 210 and the horizontal plane, and the sand blowing angle is selected from 30 degrees, 45 degrees, 60 degrees and 90 degrees;
calculating the relative linear speed of the front edge of the blade according to the rotating speed of the rotor and the length of the blade in the service process of the blade of the helicopter, wherein the sand blowing speed is selected from 30m/s, 80m/s, 130m/s, 180m/s and 220 m/s;
according to the sand dust types in China and the world, sand stones with two size distributions are selected: the golf course sand belongs to imitation ASand in rich areas: [ the size distribution is 45-250 μm < 100 μm and accounts for 75%];AL2O3Belongs to common quartz sand: (0-149 μm about 5%, 149-600 μm about 90%; more than 5% above 600 μm);
in the step S3, according to the global climate state, the temperature of 5 ℃, 25 ℃ and 50 ℃ are selected for the examination test;
s4: performing a test according to the test parameter matrix determined in the step S3;
in the step S4, performing a parallel test, as shown in table 1 below, selecting 3 parallel test pieces;
table 1 test matrix for planar parts
S5: evaluation of test results
Wherein, the test temperature is 25 ℃, the sand blowing angle is 30 degrees, the sand blowing speed is 130m/s, the sand in the Afghanistan-like region is adopted, after the test sample is subjected to the sand erosion test for 1min, the test surface is eroded, a pit is flushed out, the erosion grade is evaluated by x and y according to the width and the depth of the pit, x represents the rain erosion depth along the thickness direction of the test piece, and the erosion grade is totally 49 grades, namely 0,0, 1,1, 2,1, 3, 1,4, 1,5, 1,6, 2 and 1 … ….
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 (8)
1. A method for evaluating the sand erosion resistance of a protective material of a helicopter rotor blade is characterized by comprising the following steps:
s1: manufacturing a rotor blade protective material test piece (100);
s2: designing a test device (200) and installing the test piece (100);
the test device (200) comprises a test bed (210), a feeding chamber (220), a mixing chamber (230), a gas supply chamber (240), a granule chamber (250) and an environmental test chamber (300); the test bed (210) is used for placing the test piece (100), a motor is installed in the test bed, and the test piece can be driven by the motor to rotate for a certain angle along the horizontal direction; the feeding chamber (220) is positioned right above the test bed (210) and is communicated with the mixing chamber (230), the grain chamber (250) and the air supply chamber (240) respectively convey sand grains and gas into the mixing chamber (230), and after the sand grains and the gas are mixed by the mixing chamber (230), sand is blown to the test piece (100) through a quartz nozzle (221) of the feeding chamber (220); the environmental test chamber (300) is used for adjusting the set environmental temperature;
s3: determining a test parameter matrix, wherein the test parameters comprise a sand blowing angle, a sand blowing speed, a sand type and a test temperature;
s4: performing a test according to the test parameter matrix determined in the step S3;
s5: and (4) evaluating test results.
2. A method for evaluating the sand erosion resistance of a helicopter rotor blade protective material according to claim 1 wherein in said step S1 said test piece (100) is a sheet-like test piece.
3. A method for evaluating the sand erosion resistance of a helicopter rotor blade protective material according to claim 1, wherein in said step S3, said sand blowing angle is adjusted by adjusting the angle between said test stand (210) and the horizontal plane, said sand blowing angle being selected from one or more of 30 °, 45 °, 60 °, and 90 °.
4. A method for evaluating the sand erosion resistance of a helicopter rotor blade protective material according to claim 3, wherein in said step S3, said sand blowing speed is selected from one or more of 30m/S, 80m/S, 130m/S, 180m/S, and 220 m/S.
5. A method according to claim 4, wherein in step S3, one or more of two size distributions of sand is selected: a. the imitation Afu region sand has the size distribution range of 45-250 mu m, wherein 75% of the imitation Afu region sand with the size smaller than 100 mu m; b. the size distribution range of the common quartz sand is about 5 percent from 0 to 149 mu m, and the size distribution range of the common quartz sand is about 90 percent from 149 mu m to 600 mu m; more than 5 percent of more than 600 mu m.
6. The method according to claim 5, wherein in step S3, the evaluation test is performed at 5 ℃, 25 ℃ and 50 ℃ according to the global climate status.
7. The method of claim 6, wherein 3 or more test pieces are selected for each of the test conditions of the sand blowing angle, the sand blowing speed, the sand type and the test temperature for performing the parallel test in step S4.
8. The method for evaluating the sand erosion resistance of a helicopter rotor blade protective material according to claim 7, wherein in said step S5, the evaluation of erosion rating is performed according to the width and depth of the pits eroded on the surface of said test piece (100).
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Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5486096A (en) * | 1994-06-30 | 1996-01-23 | United Technologies Corporation | Erosion resistant surface protection |
CN101558174A (en) * | 2005-09-23 | 2009-10-14 | Uit有限责任公司 | Method of metal performance improvement and protection against degradation and suppression thereof by ultrasonic impact |
CN105738235A (en) * | 2016-04-28 | 2016-07-06 | 内蒙古工业大学 | Corrosion experiment and injury evaluation methods of engineering material under wind sand environment |
CN107202740A (en) * | 2017-07-18 | 2017-09-26 | 西北工业大学 | It is a kind of to simulate the experimental rig for washing away fatigue |
CN108254275A (en) * | 2018-01-04 | 2018-07-06 | 湘潭大学 | Thermal barrier coating Work condition analogue and real-time monitoring device |
CN109142025A (en) * | 2017-06-27 | 2019-01-04 | 南京理工大学 | A kind of high temperature and pressure contains solid multiphase Particle Erosion abrasion test device |
CN109406326A (en) * | 2018-12-26 | 2019-03-01 | 内蒙古工业大学 | The detection system of abrasion test device and mechanical part |
CN110018074A (en) * | 2019-04-30 | 2019-07-16 | 盐城工业职业技术学院 | A kind of aircraft external surface coating abrasion resistance testing device |
CN110793906A (en) * | 2018-08-03 | 2020-02-14 | 中国电子产品可靠性与环境试验研究所((工业和信息化部电子第五研究所)(中国赛宝实验室)) | Method for testing weather resistance of coating in dry and hot environment |
CN110793908A (en) * | 2019-10-11 | 2020-02-14 | 中国直升机设计研究所 | Laboratory accelerated test method for shipborne helicopter coating under marine atmospheric condition |
-
2020
- 2020-11-20 CN CN202011326433.8A patent/CN112414932A/en active Pending
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5486096A (en) * | 1994-06-30 | 1996-01-23 | United Technologies Corporation | Erosion resistant surface protection |
CN101558174A (en) * | 2005-09-23 | 2009-10-14 | Uit有限责任公司 | Method of metal performance improvement and protection against degradation and suppression thereof by ultrasonic impact |
CN105738235A (en) * | 2016-04-28 | 2016-07-06 | 内蒙古工业大学 | Corrosion experiment and injury evaluation methods of engineering material under wind sand environment |
CN109142025A (en) * | 2017-06-27 | 2019-01-04 | 南京理工大学 | A kind of high temperature and pressure contains solid multiphase Particle Erosion abrasion test device |
CN107202740A (en) * | 2017-07-18 | 2017-09-26 | 西北工业大学 | It is a kind of to simulate the experimental rig for washing away fatigue |
CN108254275A (en) * | 2018-01-04 | 2018-07-06 | 湘潭大学 | Thermal barrier coating Work condition analogue and real-time monitoring device |
CN110793906A (en) * | 2018-08-03 | 2020-02-14 | 中国电子产品可靠性与环境试验研究所((工业和信息化部电子第五研究所)(中国赛宝实验室)) | Method for testing weather resistance of coating in dry and hot environment |
CN109406326A (en) * | 2018-12-26 | 2019-03-01 | 内蒙古工业大学 | The detection system of abrasion test device and mechanical part |
CN110018074A (en) * | 2019-04-30 | 2019-07-16 | 盐城工业职业技术学院 | A kind of aircraft external surface coating abrasion resistance testing device |
CN110793908A (en) * | 2019-10-11 | 2020-02-14 | 中国直升机设计研究所 | Laboratory accelerated test method for shipborne helicopter coating under marine atmospheric condition |
Non-Patent Citations (3)
Title |
---|
上海玻璃钢结构研究所: "《玻璃钢结构设计》", 29 February 1980, 北京:中国建筑工业出版社 * |
潘焕友等: "直升机桨叶耐颗粒物/砂磨蚀标准分析", 《直升机技术》 * |
马松林: "TC4 平板受砂尘高速冲蚀试验方法与损伤规律研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》 * |
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