CN114544409A - Testing device and testing method for landing impact friction wear of aircraft tire - Google Patents
Testing device and testing method for landing impact friction wear of aircraft tire Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/56—Investigating resistance to wear or abrasion
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N19/00—Investigating materials by mechanical methods
- G01N19/02—Measuring coefficient of friction between materials
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/30—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight
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- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J2005/0077—Imaging
Abstract
The application provides a test device and a test method for aircraft tire landing impact friction wear, the test device is fixedly connected with a rotating shaft through a test piece clamping device for rubber wheels for simulating aircraft tires, a grinding wheel fastening device for grinding wheels for simulating road surface tests is installed on a servo motor, the relative height of the rubber wheels and the grinding wheels is adjusted through adjusting the height of a height adjusting block clamped on an impact support, the side inclination angle of the rubber wheels is adjusted through rotating an inclination angle adjusting shaft and clamping and fixing the inclination angle adjusting shaft on a height adjusting block, the side inclination angle of the rubber wheels is adjusted through rotating a side inclination adjusting shaft and clamping and fixing the side inclination angle adjusting shaft on a connecting arm, the impact loading force is controlled through changing the weight of a loading weight, a reset blocking strip is shifted through the rotation of a reset shifting handle, and an impact test is carried out after a stamping plate is reset. The device has the advantages of simple structure, low cost, high data precision and capability of simply, conveniently and quickly simulating the landing impact friction wear of the aircraft tire, and can provide reliable basis for the research and development of aircraft tire materials.
Description
Technical Field
The invention relates to the field of testing of aviation tire friction performance, in particular to a testing device and a testing method for aviation tire landing impact friction wear.
Background
The aircraft tire is the only part of the aircraft contacting with the road surface, plays a role in supporting load and transmitting braking force, driving force and steering force to the ground, plays a vital role in an undercarriage system, and is the key for ensuring the landing and sliding safety and performance of the aircraft.
However, aircraft landing often involves high-speed running and violent impact, and besides, the aircraft tires are severely worn by effective braking, unevenness of the ground, variable weather conditions and other factors. Particularly under the impact working condition, the tread rubber is subjected to high-speed friction under the combined action of high speed and high pressure, so that the temperature is rapidly increased, a large amount of white smoke is generated, black marks are left on a runway, the tread wear degree is rapidly increased, and the taking-off and landing safety of an airplane is seriously threatened.
The frictional wear characteristic of the tread rubber material in a high-speed impact service environment is an important index for measuring the comprehensive performance of the aircraft tire. The existing experimental device and research method mostly focus on rubber sliding friction and wear behaviors under working conditions of different speeds, pressures and the like, and cannot reflect the friction and wear characteristics of rubber in the landing impact process of an airplane. In addition, the tire is often accompanied by lateral deviation and a slip angle during landing, and a certain slip rate exists in the rolling process of the tire, so that the frictional wear characteristic of the rubber under the series of working conditions cannot be accurately obtained, so that the data error measured by the conventional experimental device is large, and the frictional wear characteristic of the rubber material of the aircraft tire cannot be truly reflected.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provides a test device and a test method for landing impact friction wear of an aircraft tire, which have simple structure and convenient use, can truly simulate the impact friction wear working condition of the aircraft tire during landing and can test the rubber impact friction wear and the heat generation characteristics under various working conditions; can provide technical support for the improved design of aviation tire structures and materials.
The technical scheme adopted by the invention for solving the defects of the prior art is as follows:
a test device for aircraft tire landing impact friction wear comprises a support rack, wherein the support rack comprises a support frame and a table top, and is characterized in that a grinding wheel friction device is arranged on the upper side of the table top, two impact guide rails are arranged on the table top on the left side of the grinding wheel friction device, a left slide block and a right slide block are respectively arranged on the two impact guide rails, a punching plate is arranged on the two left slide blocks, impact load plates are arranged on the two right slide blocks, the punching plate and the impact load plates are connected through a one-dimensional force sensor I, a lateral force guide rail is arranged on the impact load plates, an impact mounting plate is arranged on the lateral force guide rail, an impact mounting plate is arranged on the impact mounting plate, a sensor mounting seat is arranged on the impact load plate on the front side of the impact mounting plate, and the sensor mounting seat is connected with the front side of the impact mounting plate through a one-dimensional force sensor II; the impact mounting plate is provided with an impact strut, the impact strut is provided with a height adjusting block, the height adjusting block is provided with an inclination angle adjusting shaft arranged in the front-back direction, the inclination angle adjusting shaft is provided with an inclination angle adjusting arm, the inclination angle adjusting arm is provided with a connecting arm arranged in the front-back direction, the connecting arm is provided with a lateral deviation adjusting shaft arranged in the left-right direction, the lateral deviation adjusting shaft is provided with a mounting table on the side opposite to the grinding wheel friction device, the mounting table is provided with a rotating shaft, a test piece clamping device is arranged on the rotating shaft on the upper side of the mounting table, a speed measuring brake disc is arranged on the rotating shaft on the lower side of the mounting table, and one side of the mounting table is provided with a speed measuring sensor and a brake matched with the speed measuring brake disc; the device is provided with an impact loading device and a loading reset device, wherein the impact loading device comprises a loading weight, a transmission steel wire rope and a guide pulley block, the loading weight is suspended at one end of the transmission steel wire rope below the table-board, and the other end of the transmission steel wire rope is connected with the punching plate after being guided by the pulley block; the loading reset device is characterized in that a reset shifting handle is arranged on a table board below the stamping plate, one end of the reset shifting handle is provided with a transfer motor, the upper side of the other end of the reset shifting handle is provided with a reset shifting wheel, and a reset barrier strip matched with the reset shifting wheel is arranged on the lower side surface of the stamping plate on the left side of the reset shifting wheel.
The grinding wheel friction device comprises a servo motor, a bearing seat, a grinding wheel and a grinding wheel fastening device. The servo motor realizes the rotary motion at different speeds, and the bearing seat bears the radial impact loading force of the grinding wheel and the axial friction force and loading force components. The grinding wheel fastening device fastens the grinding wheel on the output shaft of the motor and synchronously rotates with the output shaft.
The one-dimensional force sensor I and the one-dimensional force sensor II are S-shaped pull pressure sensors.
A weight frame is arranged on the lower side of the table board, two guide sliding rods (vertically arranged) are arranged on the weight frame, a weight plate capable of freely sliding up and down is arranged on each guide sliding rod, a weight penetrating rod (vertically arranged) is arranged on the weight plate between the two guide sliding rods, and one end of a transmission steel wire rope is connected with the weight plate.
The speed measuring brake disc is characterized in that detection holes are uniformly distributed in the circumferential direction of the edge of the brake disc, and the speed measuring sensors are photoelectric opposite-type sensors which are matched with the detection holes for detection and arranged on the upper side and the lower side of the brake disc. When the brake disc rotates, the sensor is influenced to the incident light, and therefore the rotation speed information of the rubber wheel is detected.
The table board is provided with a temperature acquisition device, and a temperature measuring head of the temperature acquisition device is positioned on one side of the grinding wheel friction device and is used for acquiring the surface temperature of the rubber wheel test piece in real time in the experimental process.
A test method for landing impact friction wear of an aircraft tire is characterized by comprising the following steps:
step one, obtaining parameters required by a test according to the simulated actual working condition of the airplane:
1.1 obtaining the maximum contact pressure P when the aircraft tire lands, selecting a rubber wheel with the diameter of 50-200mm and the thickness of 3-100mm, and calculating the weight of a loaded weight according to the maximum contact pressure P when the aircraft tire lands;
1.2 obtaining the maximum vertical speed v of the aircraft tire during landinggDetermining the maximum impact loading speed V of the reset dial wheelload，Vload＝vg；
According to the formula:
calculate resetRotating speed n of the handleb；
In the formula, nbThe rotating speed (r/min) of the reset shifting handle is adopted; r is the length of the reset shifting handle; beta is the included angle (degree) of the reset shifting handle and the motion direction of the impact mounting plate when the rubber wheel is contacted with the grinding wheel.
1.3 according to the horizontal linear velocity v of the aircraft tire groundjdCalculating the rotating speed n of the grinding wheel;
in the formula vjdThe horizontal linear velocity of the ground contact of the aircraft tire during landing, n is the rotating speed of the grinding wheel, pi is the circumferential rate, d is the diameter of the grinding wheel, cyjdThe coefficient of the grounding lift is m, the mass of the airplane is g, the gravity acceleration is g, rho is the air density, and S is the wing area of the airplane.
1.4, obtaining the roll-off angle and the roll angle of the rubber wheel according to the friction test research requirement or the actual roll-off angle and roll angle when the aircraft tire lands;
step two, mounting the rubber wheel on the test piece clamping device; placing a loading weight on a weight tray, adjusting a lateral deviation angle and a lateral inclination angle, and controlling the rotating speed of a grinding wheel; controlling the rotation and the periodic loading of the transfer motor according to the rotating speed of the reset shifting handle to perform an impact test;
step three, the one-dimensional force sensor I collects loading force in real time, the one-dimensional force sensor II collects friction force in the tangential direction of the grinding wheel in real time, and the thermal imager collects the temperature of the rubber wheel on a friction interface in real time;
and step four, using the acquired sensor data, dividing the tangential force of the grinding wheel by the radial force of the grinding wheel to obtain a friction coefficient, obtaining the abrasion loss through the mass change of the rubber wheel before and after a weighing experiment, obtaining the abrasion appearance through shooting the texture of the abrasion surface of the rubber wheel by an optical digital microscope, and obtaining the temperature rise history and the temperature field of the rubber on the abrasion surface through the acquisition result of the thermal imager. And evaluating the quality of the aircraft tire tread material according to the abrasion loss, the abrasion morphology, the temperature rise history and the temperature field distribution.
The invention can adopt a tire footprint tester to measure the contact pressure of the rubber wheel under different loading forces. The weight of the loaded weight divided by the tire footprint area yields the (average) contact pressure.
V in the inventiong＝vA-ωLcosα；
In the formula, vAIs the vertical velocity at the aircraft ADIRU, ω is the aircraft pitch rate, L is the distance from the aircraft ADIRU to the main landing gear, and α is the aircraft pitch angle. v. ofAω, L, α can be obtained from aircraft QAR data. According to the requirements of civil aviation regulation, the vertical speed v in the limit working conditions such as forced landing process and the likegNot more than 1.524m/s, and the maximum impact loading speed (V) of the thumb wheel during the simulation test of civil aviation aircraft tiresloadmax) Is 1.524 m/s.
The invention further improves that the aircraft tire slip ratio S of the tire is calculated according to the brake braking parameter and the airplane parameter when the (simulated) aircraft tire landsg
In the formula:
in order to obtain the slip ratio,
is a first order equation of slip ratio, vjdThe landing and taxiing speed of the airplane, D is aerodynamic drag, k is main wheel load distribution coefficient (airplane parameter manual), and LsIs the aircraft lift (aircraft parameter handbook), r is the tire radius, and J is the main engine wheelThe moment of inertia (an airplane parameter manual), mu is the friction coefficient between the tire and the road surface (obtained by testing), and T is the braking moment (the airplane parameter manual); cDIs the lift coefficient of the aircraft, CLThe drag coefficient of the airplane, m is the (total) mass of the airplane, g is the gravitational acceleration, ρ is the air density, and S is the wing area (actual parameter) of the airplane.
Dividing the difference value of the linear speed of the grinding wheel and the linear speed of the rubber wheel by the linear speed of the grinding wheel to obtain the slip rate; the brake is controlled according to the obtained slip ratio. The test can be carried out under the condition that the tested rubber wheel has the same slip rate.
By the formula
Calculating the linear velocity V of the contact surface of the grinding wheel and the rubber wheel, wherein omega is the angular velocity (rad/s) of the rubber wheel; reIs the rolling radius (mm) of the rubber wheel; v is the linear speed (m/s) of the contact surface of the grinding wheel and the rubber wheel.
And n is V/pi d is the target rotating speed of the rubber wheel, and the brake is controlled to work according to the target rotating speed of the rubber wheel and the actual rotating speed (using a PID (proportion integration differentiation) controller) of the rubber wheel detected by the speed measuring sensor. The brake is a pneumatic disc brake matched with the brake disc; the pneumatic disc brake is connected with the air source, when the air source outputs different air pressures, different clamping forces of the brake cylinder on the brake disc can be achieved, and different slip rates between the rubber wheel and the grinding wheel are achieved. The aircraft tire friction and wear performance under different slip rate working conditions can be measured.
The invention provides a test device for landing impact friction wear of an aircraft tire, which is characterized in that a test piece clamp for a rubber wheel for simulating an aircraft tire is fixedly connected with a rotating shaft, a grinding wheel for simulating a road surface test is mounted on a servo motor by a grinding wheel fastening device, the relative height of the rubber wheel and the grinding wheel is adjusted by adjusting the height of a height adjusting block clamped on an impact support, the side inclination angle of the rubber wheel is adjusted by rotating an inclination angle adjusting shaft and clamping and fixing the inclination angle adjusting shaft on a height adjusting block, the side inclination angle of the rubber wheel is adjusted by rotating a side inclination adjusting shaft and clamping and fixing the side inclination adjusting shaft on a connecting arm, the weight of a loading weight is changed to control the impact loading force, and a reset blocking strip is shifted by rotating a reset shifting handle to drive a stamping plate to reset for impact test. Under the set rotating speed of the grinding wheel, the rubber wheel is driven to repeatedly impact the grinding wheel under the set working condition, the working condition of the aircraft tire during landing is simulated, and the sensors obtain corresponding test data, so that performance data of the aircraft tire manufactured by the rubber wheels made of different materials can be analyzed and obtained. The device has the advantages of simple structure and low cost, can simply, conveniently and quickly simulate the landing impact friction and wear of the aircraft tire, has high precision of the obtained friction and wear data, and can provide reliable basis for the research and development of aircraft tire materials.
Drawings
FIG. 1 is a schematic view of the structure of a test apparatus according to the present invention.
FIG. 2 is a schematic perspective view of the test apparatus of the present invention.
FIG. 3 is a schematic perspective view of the test apparatus of the present invention with the wheel friction unit and the temperature acquisition unit removed.
Fig. 4 is a schematic perspective view of fig. 3 with the support stand removed.
Fig. 5 is a schematic perspective view of the loading reset device of the present invention.
FIG. 6 is a graph of temperature rise history of a rubber wheel collected during an experiment.
FIG. 7 is a friction force profile collected during the test.
Detailed Description
The aircraft tire landing impact friction wear test device shown in fig. 1-5 comprises a support bench, wherein the support bench comprises a support frame 1 and a table top 20, a grinding wheel friction device is arranged on the upper side of the table top 20, a grinding wheel of the grinding wheel friction device is horizontally arranged and can freely rotate, and the grinding wheel friction device comprises a servo motor 15, a bearing seat 14, a grinding wheel 13 and a grinding wheel fastening device 12. As can be seen from fig. 1 and 2, the servo motor 15 is fixedly arranged at the lower side of the table top 20, and the bearing seat 14 is arranged at the upper side of the table top 20. A transmission shaft is arranged in the bearing seat 14 through a bearing, and the lower end of the transmission shaft is connected with an output shaft of a servo motor 15; the grinding wheel fastening device 12 is characterized in that a lower fixing piece and an upper fixing piece are arranged at the upper part of a transmission shaft, and a grinding wheel 13 is clamped and fixed on the lower fixing piece through a nut and the upper fixing piece; the servo motor realizes the rotary motion at different speeds, and the bearing seat bears the radial impact loading force of the grinding wheel and the axial friction force and loading force components. The grinding wheel fastening device fastens the grinding wheel on the output shaft of the motor and synchronously rotates with the output shaft of the motor. An impact base plate 28 is arranged on a table top on the left side of the grinding wheel friction device, two impact guide rails 21 which are parallel to each other and arranged in the left-right direction are arranged on the impact base plate 28, the two impact guide rails 21 which are parallel to each other are linear guide rails, a left slide block and a right slide block are respectively arranged on the two impact guide rails 21, a stamping plate 16 is arranged on the two left slide blocks, an impact load plate 34 is arranged on the two right slide blocks, the stamping plate 16 and the impact load plate 34 are connected through a one-dimensional force sensor I, the one-dimensional force sensor I is an S-shaped pulling pressure sensor, a lateral force guide rail 25 arranged in the front-back direction is arranged on the impact load plate 34, an impact mounting plate is arranged on the lateral force guide rail 25, an impact mounting plate 24 is arranged on the impact mounting plate, a sensor mounting seat is arranged on the impact load plate 34 on the front side of the impact mounting plate 24, and the sensor mounting seat is connected with the front side of the impact mounting plate 24 through a one-dimensional force sensor II 29, the one-dimensional force sensor II is an S-shaped pulling pressure sensor; the impact mounting plate 24 is provided with an impact strut 8 which is arranged in the vertical direction, the impact strut 8 is provided with a height adjusting block 9, the adjusting block 9 is provided with a clamping hole, the adjusting block 9 at one side of the clamping hole is provided with an elastic notch, the adjusting block 9 is provided with an adjusting screw for changing the size of the elastic notch, the impact strut is arranged in the clamping hole, the adjusting screw is screwed, the adjusting block 9 is clamped and fixed on the impact strut 8, the adjusting screw is loosened, the elastic notch is enlarged, and the adjusting block 9 can adjust the height on the impact strut 8; the height of the height adjusting block 9 on the impact strut 8 can be adjusted as desired. The height adjusting block 9 is provided with an inclination angle adjusting shaft 10 arranged in the front-back direction, an inclination angle adjusting arm 17 is arranged on the inclination angle adjusting shaft 10, and the inclination angle adjusting shaft 10 can rotate on the height adjusting block to adjust the included angle between the inclination angle adjusting arm and the horizontal (impact mounting plate). The tilt angle adjusting arm 17 is provided with a connecting arm 171 arranged in the front-rear direction, the connecting arm 171 is provided with a lateral deviation adjusting shaft arranged in the left-right direction, and the connecting structure between the connecting arm 171 and the lateral deviation adjusting shaft, the connecting structure between the tilt angle adjusting arm 17 and the tilt angle adjusting shaft 10 and the connecting structure between the adjusting block and the impact support are the same. An installation platform 23 is arranged on the side opposite to the grinding wheel friction device on the lateral deviation adjusting shaft, a vertically through rotating shaft is arranged on the installation platform 23, a test piece clamping device 19 is arranged on the rotating shaft on the upper side of the installation platform 23, and the structure of the test piece clamping device 19 is the same as that of the grinding wheel fastening device. A speed measuring brake disc 33 is arranged on the rotating shaft at the lower side of the mounting platform 23, and a speed measuring sensor 32 matched with the speed measuring brake disc 33 is arranged on one side of the mounting platform 23; as can be seen from the figure, the speed measuring brake disc 33 has detection holes uniformly distributed on the periphery of the brake disc, and the speed measuring sensors are photoelectric correlation sensors arranged on the upper and lower sides of the brake disc and matched with the detection holes for detection; when the brake disc rotates, the sensor is influenced to the incident light, and therefore the rotation speed information of the rubber wheel is detected. The other side of the mounting table 23 is provided with a brake 22 matched with the speed measuring brake disc 33, and the brake 22 is a disc brake; the device is provided with an impact loading device and a loading resetting device, wherein the impact loading device comprises a loading weight 5, a transmission steel wire rope 31 and a guide pulley block 26, the loading weight 5 is hung at one end of the transmission steel wire rope 31 below the table board, the other end of the transmission steel wire rope 31 is connected with a stamping plate 16 after being guided by the guide pulley block 26, a connecting seat 40 is arranged at the lower side of the stamping plate 16, and the other end of the transmission steel wire rope 31 is connected with the connecting seat 40; the loading reset device is characterized in that a reset shifting handle 38 which is horizontally arranged and is parallel to the stamping plate 16 (both the reset shifting handle and the stamping plate are horizontally arranged) is arranged on the impact base plate 28 on the table board below the stamping plate 16, one end part of the reset shifting handle 38 is connected with a transfer motor 6 for driving the reset shifting handle to rotate, the upper side of the other end part of the reset shifting handle is provided with a reset shifting wheel 30, and the lower side surface of the stamping plate 16 on the left side of the reset shifting wheel 30 is provided with a reset barrier strip 39 matched with the reset shifting wheel; as can be seen from the figure, the transfer motor 6 is fixedly arranged at the lower side of the stamping plate 16, and the transfer motor 6 consists of a motor and a speed reducer. The transfer motor 6 works to drive the reset dial handle 38 to rotate, and the reset dial wheel 30 is matched with the reset barrier strip 39 and can dial the punching plate 16 to move leftwards. The table top is provided with a temperature acquisition device 11, a temperature measuring head of the temperature acquisition device 11 is positioned on one side of the grinding wheel friction device, and when the grinding wheel friction device is used, the temperature measuring head of the temperature acquisition device 11 is opposite to the contact part of the rubber wheel and the grinding wheel and is used for acquiring the surface temperature of a rubber wheel test piece in real time in the experimental process; the temperature acquisition device 11 is a thermal imager.
The invention is further improved, a weight frame 2 is arranged on the lower side of the table-board 20, two guide slide rods 4 vertically arranged up and down are arranged on the weight frame 2, a weight plate 3 capable of freely sliding up and down is arranged on the guide slide rods 4, a weight penetrating rod 7 vertically arranged up and down is arranged on the weight plate 3 between the two guide slide rods 4, and one end of a transmission steel wire rope 36 is connected with the weight plate.
A test method for landing impact friction wear of an aircraft tire is characterized by comprising the following steps:
step one, obtaining parameters required by a test according to the simulated actual working conditions (using the aircraft tire) of the aircraft in the using process:
1.1 obtaining the (average) maximum contact pressure P at the time of landing of the aircraft tyre being simulated; according to the load and air pressure in the aviation tire standard, the contact pressure P is obtained by adopting finite element simulation calculation or using a pressure blanket test. Selecting a rubber wheel with the diameter of 60-100mm and the thickness of 5-20mm, and calculating the weight of the loaded weight according to the maximum contact pressure P when the aircraft tire lands;
1.2 obtaining the maximum vertical speed v of the aircraft tire during landinggDetermining the maximum impact loading speed V of the reset dial wheelload，Vload＝vg；
According to the formula:
calculating the rotating speed n of the reset dial handleb(i.e. the rotational speed of the transfer motor, n)b＝30000vload/πrsinβ)，
In the formula, nbThe rotating speed (r/min) of the reset shifting handle is adopted; r is the length of the reset dial handle (the distance between the axis of the transfer motor and the axis of the reset dial shaft) (mm); beta is an included angle (DEG) between the reset shifting handle and the motion direction (front and back direction) of the impact mounting plate when the rubber wheel is contacted with the grinding wheel, and the beta is usually a certain value between 30 and 90 degrees.
1.3 according to the horizontal linear velocity v of the aircraft tire groundjdCalculating the rotating speed n of the grinding wheel;
in the formula vjdThe ground contact horizontal linear velocity (QAR data) of an aircraft tire during landing, n is the rotating speed of a grinding wheel, pi is the circumferential rate, d is the diameter of the grinding wheel, cyjdThe groundlift coefficient (QAR data) is defined as m being the (total) mass of the aircraft, g being the gravitational acceleration ρ being the air density, and S being the aircraft wing area (actual parameter).
1.4, acquiring the yaw angle and the roll angle of the rubber wheel (acquired from QAR data of the airplane) according to the research requirement of a friction test or the actual yaw angle and roll angle of an aircraft tire during landing;
step two, according to the parameters obtained in the step 1, installing a rubber wheel 18 for testing on a test piece clamping device 19; placing a loading weight 5 on a weight plate 3, adjusting the lateral deviation angle and the lateral inclination angle, and controlling the rotating speed of the grinding wheel (so that the peripheral linear speed of the grinding wheel meets the requirement); controlling the rotation and the periodic loading of the transfer motor according to the rotating speed n of the reset transfer handle to perform an impact test;
step three, the first one-dimensional force sensor collects impact load in real time, the second one-dimensional force sensor collects friction force in the tangential direction of the grinding wheel in real time, and the temperature collection device collects the temperature of the rubber wheel on a friction interface in real time;
and step four, using the acquired sensor data, dividing the tangential force of the grinding wheel by the radial force (impact load) of the grinding wheel to obtain a friction coefficient, obtaining the abrasion loss through the mass change of the rubber wheel before and after a weighing experiment, obtaining the abrasion appearance through shooting the texture of the abrasion surface of the rubber wheel by an optical digital microscope, and obtaining the temperature rise history and the temperature field of the rubber on the friction surface through the acquisition result of a thermal imager. And evaluating the quality of the aircraft tire tread material according to the abrasion loss, the abrasion morphology, the temperature rise history and the temperature field distribution. In the invention, the contact pressure (measured contact area and obtained) of the rubber wheel under different loading forces (loading weight) can be measured by adopting a tire footprint tester. The weight of the loaded weight divided by the tire footprint area yields the (average) contact pressure.
In the inventionV isg＝vA-ωLcosα；
In the formula, vAIs the vertical velocity at the aircraft ADIRU, ω is the aircraft pitch rate, L is the distance from the aircraft ADIRU to the main landing gear, and α is the aircraft pitch angle. v. ofAω, L, α can be obtained from aircraft QAR data. According to the requirements of civil aviation regulation, the vertical speed v in the limit working conditions such as forced landing process and the likegNot more than 1.524m/s, and the maximum impact loading speed (V) of the thumb wheel during the simulation test of civil aviation aircraft tiresloadmax) Is 1.524 m/s.
The invention further improves that the aircraft tire slip ratio S of the tire is calculated according to the brake braking parameter and the airplane parameter when the (simulated) aircraft tire landsg
In the formula:
in order to obtain the slip ratio,
is a first order equation of slip ratio, vjdThe landing and taxiing speed of the airplane, D is aerodynamic drag, k is main wheel load distribution coefficient (airplane parameter manual), and LsThe method is characterized in that the method is an aircraft lift force (an aircraft parameter manual), r is a tire radius, J is a main engine wheel rotating inertia (the aircraft parameter manual), mu is a friction coefficient (obtained by testing) between a tire and a road surface, and T is a braking moment (the aircraft parameter manual); cDIs the lift coefficient of the aircraft, CLIs the drag coefficient of the aircraft, m is the (total) mass of the aircraft, gIs the acceleration of gravity, ρ is the air density, and S is the aircraft wing area (actual parameter).
Dividing the difference value of the linear speed of the grinding wheel and the linear speed of the rubber wheel by the linear speed of the grinding wheel to obtain the slip rate; the brake is controlled according to the obtained slip ratio. The test can be carried out under the condition that the tested rubber wheel has the same slip rate.
By the formula
For the slip rate, the formula is modified, the linear velocity V of the contact surface of the grinding wheel and the rubber wheel is calculated,
wherein Ω is rubber wheel angular velocity (rad/s); reIs the rolling radius (mm) of the rubber wheel; v is the linear speed (m/s) of the contact surface of the grinding wheel and the rubber wheel.
And n-pi d/V is the target rotating speed of the rubber wheel, and the brake is controlled to work according to the target rotating speed of the rubber wheel and the actual rotating speed (using a PID controller) of the rubber wheel detected by the speed measuring sensor. The brake is a pneumatic disc brake matched with the brake disc; the pneumatic disc brake is connected with the air source, when the air source outputs different air pressures, different clamping forces of the brake cylinder on the brake disc can be achieved, and different slip rates between the rubber wheel and the grinding wheel are achieved.
In the invention, the contact pressure of the rubber wheel under different loading forces (loading weight) can be measured by adopting a tire footprint tester. The weight of the loaded weight divided by the tire footprint area yields (average)) the contact pressure (pressure per unit area, i.e., pressure)
V in the inventiong＝vA-ωLcosα；
In the formula, vAThe vertical speed of the ADIRU of the airplane is shown, omega is the pitching change rate of the airplane, L is the distance from the ADIRU of the airplane to a main landing gear, and alpha is the pitching angle of the airplane (alpha is the included angle (degree) between the reset shifting handle and the motion direction (front and back direction) of the impact mounting plate when the rubber wheel is in contact with the grinding wheel). v. ofAω, L, α can be obtained from aircraft QAR data. The upper limit theoretical data of the pitching angle alpha of the airplane is 11 degrees. According to the requirements of civil aviation regulation, the vertical speed v in the limit working conditions such as forced landing process and the likegNot more than 1.524m/s, simulation testMaximum impact loading velocity (V) of thumb wheel during testing of civil aviation aircraft tiresloadmax) Is 1.524 m/s.
The invention can calculate the (average) maximum contact pressure P when the aircraft tire lands by adopting a finite element simulation method according to the load and air pressure in the aircraft tire standard, and can also obtain the contact pressure P by using a pressure blanket test. When a finite element method is adopted for calculation, a simulation model of the rubber wheel and the simulated road surface is established, and the simulation model is specifically shown in figure 2; acquiring the maximum load and rated inflation pressure of the corresponding aircraft tire according to GB/T9746-2013 standard, and measuring the corresponding contact area by using a tire footprint tester; calculating the maximum contact pressure P of the aircraft tire according to the ratio of the contact areas of the tire (with the ground) under the maximum load of the aircraft tire; according to the GB/T1689-2014 standard, in order to facilitate abrasion, the standard outer diameter of the rubber wheel is determined to be 80mm, the width of the rubber wheel is determined to be 18mm, a finite element method is adopted, a simulation model of the rubber wheel and a simulated road surface is established, contact pressure under different loads can be calculated, based on the contact pressure, the maximum contact pressure P calculated by the aircraft tire can be used for really applying a load F on the rubber wheel, the safety multiple is 1.5, and the actual maximum loading weight (load) can be obtained.
Example 1
According to the national standard GB/T9746 of the aircraft tire, taking a Boeing 737-plus 800 type aircraft as an example, the maximum load of a main wheel of 46X17R20 is 20870kg, and the maximum contact pressure is about 2.5MPa according to the actual contact area; under the influence of factors such as weather, a certain side inclination and a certain side deviation exist when the aircraft tire lands, and the maximum side inclination and the side deviation do not exceed 10 degrees according to statistics.
The selected size is direct 80mm, the thickness is 18mm, and the maximum contact area is 300mm2Carrying out simulation tests on left and right (obtained by actual measurement) rubber wheels, and setting the side deflection angle and the camber angle of the rubber wheels to be 10 degrees; calculating to obtain a loading weight 650N; according to the formula
Calculating the rotating speed n of the reset dial handle driven by the motorb86.8r/min (impact loading at 86.8 r/min);
according to Boeing 737-The maximum landing speed of commercial airplanes such as model airplanes is 270km/h, the actually measured diameter of the grinding wheel is 400mm, and the maximum landing speed is calculated according to a formula
Calculating the rotating speed n of the grinding wheel as 3582.8r/min
Step two, according to the parameters obtained in the step 1, installing a rubber wheel 18 for testing on a test piece clamping device 19; placing a loading weight 5 on a weight plate 3, adjusting the lateral deviation angle and the lateral inclination angle, and controlling the rotating speed of the grinding wheel (so that the peripheral linear speed of the grinding wheel meets the requirement); controlling the rotation and the periodic loading of the transfer motor according to the rotating speed n of the reset transfer handle to perform an impact test;
step three, the first one-dimensional force sensor collects impact load in real time, the second one-dimensional force sensor collects friction force in the tangential direction of the grinding wheel in real time, and the temperature collection device collects the temperature of the rubber wheel on a friction interface in real time;
and step four, using the acquired sensor data, dividing the tangential force of the grinding wheel by the radial force (impact load) of the grinding wheel to obtain a friction coefficient, obtaining the abrasion loss through the mass change of the rubber wheel before and after a weighing experiment, obtaining the abrasion appearance through shooting the texture of the abrasion surface of the rubber wheel by an optical digital microscope, and obtaining the temperature rise history and the temperature field of the rubber on the friction surface through the acquisition result of a thermal imager. And evaluating the quality of the aircraft tire tread material according to the abrasion loss, the abrasion morphology, the temperature rise history and the temperature field distribution. In the invention, the contact pressure (measured contact area and obtained) of the rubber wheel under different loading forces (loading weight) can be measured by adopting a tire footprint tester. The weight of the loaded weight divided by the tire footprint area yields the (average) contact pressure.
According to the device structure and the test method, impact friction and high-speed friction under different lateral deflection and inclination angles under different simulated actual landing working conditions of the aircraft tire can be realized, important parameters such as temperature distribution, friction force, temperature history curves and the like are obtained, a basis is provided for design and evaluation of an aircraft tire tread formula, and technical support is provided for development of a high-performance aircraft tire. As can be seen from the figures 6 and 7, the impact friction data of the rubber wheels made of different materials under different working conditions can be measured specifically, the data is accurate and reliable, and specific data support can be provided for the design and evaluation of the aircraft tire tread formula.
Claims (9)
1. A test device for aircraft tire landing impact friction wear comprises a support rack, wherein the support rack comprises a support frame and a table top, and is characterized in that a grinding wheel friction device is arranged on the upper side of the table top, two impact guide rails are arranged on the table top on the left side of the grinding wheel friction device, a left slide block and a right slide block are respectively arranged on the two impact guide rails, a punching plate is arranged on the two left slide blocks, impact load plates are arranged on the two right slide blocks, the punching plate and the impact load plates are connected through a one-dimensional force sensor I, a lateral force guide rail is arranged on the impact load plates, an impact mounting plate is arranged on the lateral force guide rail, an impact mounting plate is arranged on the impact mounting plate, a sensor mounting seat is arranged on the impact load plate on the front side of the impact mounting plate, and the sensor mounting seat is connected with the front side of the impact mounting plate through a one-dimensional force sensor II; the impact mounting plate is provided with an impact strut, the impact strut is provided with a height adjusting block, the height adjusting block is provided with an inclination angle adjusting shaft arranged in the front-back direction, the inclination angle adjusting shaft is provided with an inclination angle adjusting arm, the inclination angle adjusting arm is provided with a connecting arm arranged in the front-back direction, the connecting arm is provided with a lateral deviation adjusting shaft arranged in the left-right direction, the lateral deviation adjusting shaft is provided with a mounting table on the side opposite to the grinding wheel friction device, the mounting table is provided with a rotating shaft, a test piece clamping device is arranged on the rotating shaft on the upper side of the mounting table, a speed measuring brake disc is arranged on the rotating shaft on the lower side of the mounting table, and one side of the mounting table is provided with a speed measuring sensor and a brake matched with the speed measuring brake disc; the device is provided with an impact loading device and a loading reset device, wherein the impact loading device comprises a loading weight, a transmission steel wire rope and a guide pulley block, the loading weight is suspended at one end of the transmission steel wire rope below the table-board, and the other end of the transmission steel wire rope is connected with the punching plate after being guided by the pulley block; the loading reset device is characterized in that a reset shifting handle is arranged on a table board below the stamping plate, one end of the reset shifting handle is provided with a transfer motor, the upper side of the other end of the reset shifting handle is provided with a reset shifting wheel, and a reset barrier strip matched with the reset shifting wheel is arranged on the lower side surface of the stamping plate on the left side of the reset shifting wheel.
2. The aircraft tire landing impact frictional wear test device as claimed in claim 1, wherein said grinding wheel friction device comprises a servo motor, a bearing seat, a grinding wheel and a grinding wheel fastening device.
3. The aircraft tire landing impact friction wear testing device as claimed in claim 1, wherein the one-dimensional force sensor I and the one-dimensional force sensor II are S-shaped tension and pressure sensors.
4. The aircraft tire landing impact friction wear test device according to claim 1, wherein a weight holder is provided on the underside of the table top, two guide slide bars are provided on the weight holder, a weight plate capable of freely sliding up and down is provided on the guide slide bars, a weight through rod is provided on the weight plate between the two guide slide bars, and one end of the transmission wire rope is connected to the weight plate.
5. The aircraft tire landing impact friction wear test device according to claim 1, wherein the speed measurement brake disc is provided with detection holes uniformly distributed in the circumferential direction of the edge of the brake disc, and the speed measurement sensors are photoelectric correlation sensors arranged on the upper side and the lower side of the brake disc and matched with the detection holes for detection.
6. The aircraft tire landing impact friction wear testing device according to claim 1, wherein the table top is provided with a temperature acquisition device, and a temperature measuring head of the temperature acquisition device is positioned on one side of the grinding wheel friction device and used for acquiring the surface temperature of the rubber wheel test piece in real time in the experimental process.
7. A test method for landing impact friction wear of an aircraft tire is characterized by comprising the following steps:
step one, obtaining parameters required by a test according to the simulated actual working condition of the airplane:
1.1 obtaining the maximum contact pressure P when the aircraft tire lands, selecting a rubber wheel with the diameter of 50-200mm and the thickness of 3-50mm, and calculating the weight of a loaded weight according to the maximum contact pressure P when the aircraft tire lands;
1.2 obtaining the maximum vertical speed v of the aircraft tire during landinggDetermining the maximum impact loading speed V of the reset dial wheelload，Vload＝vg(ii) a According to the formula:
calculating the rotating speed n of the reset dial handleb；
In the formula, nbThe rotating speed (r/min) of the reset shifting handle is adopted; r is the length of the reset shifting handle; beta is an included angle (DEG) between the reset shifting handle and the motion direction of the impact mounting plate when the rubber wheel is contacted with the grinding wheel;
1.3 according to the horizontal linear velocity v of the aircraft tire groundjdCalculating the rotating speed n of the grinding wheel;
in the formula vjdThe horizontal linear velocity of the ground contact of the aircraft tire during landing, n is the rotating speed of the grinding wheel, pi is the circumferential rate, d is the diameter of the grinding wheel, cyjdThe coefficient of the grounding lift is m, the mass of the airplane is g, the gravity acceleration is g, the rho is the air density, and the S is the wing area of the airplane;
1.4, obtaining the roll-off angle and the roll angle of the rubber wheel according to the friction test research requirement or the actual roll-off angle and roll angle when the aircraft tire lands;
step two, installing the rubber wheel on the test piece clamping device; placing a loading weight on a weight tray, adjusting a lateral deviation angle and a lateral inclination angle, and controlling the rotating speed of a grinding wheel; controlling the rotation and the periodic loading of the transfer motor according to the rotating speed of the reset shifting handle to perform an impact test;
step three, the one-dimensional force sensor I collects loading force in real time, the one-dimensional force sensor II collects friction force in the tangential direction of the grinding wheel in real time, and the thermal imager collects the temperature of the rubber wheel on a friction interface in real time;
and step four, using the acquired sensor data, dividing the tangential force of the grinding wheel by the radial force of the grinding wheel to obtain a friction coefficient, obtaining the abrasion loss through the mass change of the rubber wheel before and after a weighing experiment, obtaining the abrasion appearance through shooting the texture of the abrasion surface of the rubber wheel by an optical digital microscope, and obtaining the temperature rise history and the temperature field of the rubber on the abrasion surface through the acquisition result of the thermal imager. And evaluating the quality of the aircraft tire tread material according to the abrasion loss, the abrasion morphology, the temperature rise history and the temperature field distribution.
8. A test method of aviation tire landing impact frictional wear as in claim 7, wherein v isg＝vA-ωLcosα；
In the formula, vAThe vertical velocity at the aircraft ADIRU, ω is the aircraft pitch rate, L is the distance from the aircraft ADIRU to the main landing gear, and α is the aircraft pitch angle.
9. The aircraft tire landing impact friction wear test method according to claim 7, wherein the aircraft tire slip ratio S of the tire is calculated according to the brake parameters and airplane parameters when the aircraft tire landsg
In the formula:
in order to obtain the slip ratio,
is a first order equation of slip ratio, vjdThe landing taxiing speed of the airplane, D is aerodynamic drag, k is main wheel load distribution coefficient, and LsThe aircraft is an aircraft lifting force, r is a tire radius, J is a main engine wheel rotation inertia, mu is a friction coefficient between the tire and a road surface, and T is a braking moment; cDIs the lift coefficient of the aircraft, CLThe drag coefficient of the airplane is shown, m is the airplane mass, g is the gravity acceleration, rho is the air density, and S is the airplane wing area;
by the formula
Calculating the linear velocity V of the contact surface of the grinding wheel and the rubber wheel for the slip rate; wherein Ω is rubber wheel angular velocity (rad/s); reIs the rolling radius (mm) of the rubber wheel; v is the linear velocity (m/s) of the contact surface of the grinding wheel and the rubber wheel;
and n-pi d/V is the target rotating speed of the rubber wheel, and the brake is controlled to work according to the target rotating speed of the rubber wheel and the actual rotating speed of the rubber wheel detected by the speed measuring sensor.
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