A test device and test method for aviation tire landing impact friction wear

Abstract

The present application provides a test device and method for aircraft tire landing impact friction and wear. The test device securely connects a rubber wheel simulating an aircraft tire to a rotating shaft using a specimen clamp. A grinding wheel simulating a road surface test is mounted on a servo motor using 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 adjustment block clamped on an impact support. The roll angle of the rubber wheel is adjusted by rotating an inclination adjustment shaft clamped on the height adjustment block. The roll angle of the rubber wheel is adjusted by rotating a yaw adjustment shaft clamped on a connecting arm. The magnitude of the impact loading force is controlled by varying the weight of a loading weight. The reset handle is rotated to toggle a reset bar, driving the stamping plate to reset before conducting an impact test. The present invention has a simple structure and low cost. It can easily and quickly simulate aircraft tire landing impact friction and wear. The data obtained is highly accurate, providing a reliable basis for the research and development of aircraft tire materials.

Description

Technical Field

[0001] The invention relates to the field of aviation tire friction performance testing, in particular to a testing device and a testing method for aviation tire landing impact friction wear. Background Art

[0002] Aircraft tires are the only parts of an aircraft that come into contact with the road surface. They support loads and transmit braking, driving, and steering forces to the ground. They play a vital role in the landing gear system and are key to ensuring the safety and performance of aircraft landing and taxiing.

[0003] However, aircraft landings often involve high-speed taxiing and violent impacts. Furthermore, factors such as effective braking, uneven surfaces, and fluctuating weather conditions often cause significant wear on aircraft tires. Especially under impact conditions, the tread rubber experiences high-speed friction under the combined effects of high speed and high pressure, rapidly heating up and producing large amounts of white smoke and leaving black marks on the runway. This significantly increases tread wear, posing a serious threat to aircraft takeoff and landing safety.

[0004] The friction and wear characteristics of tread rubber materials under high-speed impact service environments are a key indicator of aircraft tire overall performance. Existing experimental devices and research methods primarily focus on the sliding friction and wear behavior of rubber under various speed and pressure conditions, failing to accurately reflect the friction and wear characteristics of rubber during aircraft landing impacts. Furthermore, tires often exhibit sideways deviation and slip angles during landing, and a certain slip rate exists during rolling. The inability to accurately measure the friction and wear characteristics of rubber under these conditions results in large errors in the data measured by existing experimental devices, failing to truly reflect the friction and wear characteristics of aircraft tire rubber materials. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and to provide a test device and method for testing the impact friction and wear of aircraft tires during landing, which has a simple structure, is easy to use, can realistically simulate the impact friction and wear conditions of aircraft tires during landing, and can test the impact friction and wear and heat generation characteristics of rubber under various working conditions; and can provide technical support for the improved design of aircraft tire structures and materials.

[0006] The technical solution adopted by the present invention to solve the above-mentioned deficiencies in the prior art is:

[0007] A test device for the landing impact friction and wear of an aircraft tire comprises a support frame, which comprises a support frame and a table, wherein the upper side of the table is provided with a grinding wheel friction device, the table on the left side of the grinding wheel friction device is provided with two impact guide rails, the two impact guide rails are respectively provided with a left slider and a right slider, the two left sliders are provided with a stamping plate, the two right sliders are provided with an impact load plate, the stamping plate and the impact load plate are connected via a one-dimensional force sensor 1, a lateral force guide rail is provided on the impact load plate, the lateral force guide rail is provided with an impact mounting plate, the impact mounting plate is provided with an impact mounting plate, the impact load plate on the front side of the impact mounting plate is provided with a sensor mounting seat, the sensor mounting seat is connected to the front side of the impact mounting plate via a one-dimensional force sensor 2; an impact pillar is provided on the impact pillar, a height adjustment block is clamped on the impact pillar, an inclination adjustment shaft arranged in the front and rear directions is clamped on the height adjustment block, an inclination adjustment arm is clamped on the inclination adjustment shaft, The angle adjustment arm is provided with a connecting arm arranged in the front and rear directions, and the connecting arm is clamped with a lateral adjustment shaft arranged in the left and right directions. A mounting platform is provided on the lateral adjustment shaft on the side opposite to the grinding wheel friction device, and a rotating shaft is provided on the mounting platform. A specimen clamp is provided on the rotating shaft on the upper side of the mounting platform, and a speed measuring brake disc is provided on the rotating shaft on the lower side of the mounting platform, and a speed sensor and brake matching the speed measuring brake disc are provided on one side of the mounting platform; an impact loading device and a loading reset device are provided, and the impact loading device includes a loading weight, a transmission wire rope and a guide pulley group, and the loading weight is suspended on one end of the transmission wire rope under the table, and the other end of the transmission wire rope is connected to the stamping plate after being guided by the pulley group; the loading reset device is provided with a reset dial handle on the table below the stamping plate, and a dial motor is provided at one end of the reset dial handle, and a reset dial wheel is provided on the upper side of the other end, and a reset baffle matching it is provided on the lower side of the stamping plate on the left side of the reset dial wheel.

[0008] The grinding wheel friction device described in the present invention includes a servo motor, a bearing seat, a grinding wheel, and a grinding wheel fastening device. The servo motor achieves rotational motion at varying speeds, while the bearing seat withstands radial impact loading forces of the grinding wheel as well as axial friction and loading components. The grinding wheel fastening device secures the grinding wheel to the motor output shaft, rotating synchronously with it.

[0009] The one-dimensional force sensor 1 and the one-dimensional force sensor 2 described in the present invention are S-type tension and pressure sensors.

[0010] The table described in the present invention is provided with a weight rack on the lower side, and two guide slide bars (vertically arranged up and down) are provided on the weight rack. The guide slide bars are provided with a weight plate that can slide freely up and down. A weight through rod (vertically arranged up and down) 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.

[0011] The speed-measuring brake disc described in this invention has detection holes evenly distributed around its circumference. The speed-measuring sensor is a photoelectric beam-type sensor located on the upper and lower sides of the disc, which cooperates with the detection holes. When the disc rotates, it affects the beam incident on the sensor, thereby detecting the rotational speed of the rubber wheel.

[0012] The table of the present invention is provided with a temperature collection device, the temperature measuring head of the temperature collection device is located on one side of the grinding wheel friction device, and is used to collect the surface temperature of the rubber wheel specimen in real time during the experiment.

[0013] A test method for aircraft tire landing impact friction and wear, characterized by comprising the following steps:

[0014] Step 1: Obtain the parameters required for the test based on the actual operating conditions of the simulated aircraft:

[0015] 1.1 Obtain the maximum contact pressure P of the aircraft tire during landing. Select a rubber wheel with a diameter of 50-200 mm and a thickness of 3-100 mm. Calculate the required loading weight based on the maximum contact pressure P of the aircraft tire during landing.

[0016] 1.2. Obtain the maximum vertical speed v when the aircraft tire lands g , determine the maximum impact loading speed V of the reset dial load , V load =v g ;

[0017] According to the formula: Calculate the reset handle speed n b ;

[0018] Where n b is the speed of the reset handle (r / min); r is the length of the reset handle; β is the angle between the reset handle and the movement direction of the impact mounting plate when the rubber wheel contacts the grinding wheel (°).

[0019] 1.3. According to the horizontal linear speed v of the aircraft tire ground contact jd Calculate the rotational speed n of the grinding wheel;

[0020]

[0021] Where v jd is the horizontal linear velocity of the aircraft tire when landing, n is the grinding wheel speed, π is the pi, d is the grinding wheel diameter, c yjd is the touchdown lift coefficient, m is the aircraft mass, g is the acceleration due to gravity, ρ is the air density, and S is the aircraft wing area.

[0022] 1.4. Obtain the rubber wheel's slip angle and roll angle based on the requirements of friction test research or the actual slip angle and roll angle of the aircraft tire during landing;

[0023] Step 2: Install the rubber wheel on the specimen fixture; place the loading weight on the weight plate, adjust the side tilt angle and side tilt angle, and control the speed of the grinding wheel; control the rotation of the dial motor according to the speed of the reset handle, periodically load, and perform the impact test;

[0024] Step 3: The first one-dimensional force sensor collects the loading force in real time, the second one-dimensional force sensor collects the 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 the friction interface in real time;

[0025] Step 4: Using the collected sensor data, the friction coefficient is calculated by dividing the grinding wheel tangential force by the grinding wheel radial force. The wear volume is calculated by measuring the change in the mass of the rubber wheel before and after the weighing test. The wear morphology is obtained by photographing the texture of the worn surface of the rubber wheel using an optical digital microscope. The temperature rise history and temperature field of the rubber on the friction surface are obtained using thermal imaging. The quality of the aircraft tire tread material is evaluated based on the wear volume, wear morphology, temperature rise history, and temperature field distribution.

[0026] In the present invention, a tire footprint tester can be used to measure the contact pressure of a rubber wheel under different loading forces. The weight of the loading weight is divided by the tire footprint area to obtain the (average) contact pressure.

[0027] The v described in the present invention g =v A -ωLcosα;

[0028] Where, v A is the vertical velocity of the aircraft at the ADIRU, ω is the aircraft pitch change rate, L is the distance from the aircraft ADIRU to the main landing gear, and α is the aircraft pitch angle. A ,ω,L,α can all be obtained from the aircraft QAR data. According to the requirements of the civil aviation regulations for the vertical speed v in extreme working conditions such as forced landing g No more than 1.524m / s, when simulating the test of civil aviation tires, the maximum impact loading speed of the thumbwheel (V loadmax ) is 1.524m / s.

[0029] The present invention is further improved to calculate the aircraft tire slip rate S of the tire according to the braking parameters of the (simulated) aircraft tire during landing and the aircraft parameters. g

[0030]

[0031]

[0032]

[0033] Where: is the slip rate, is the first-order formula for slip rate, v jd is the landing taxiing speed of the aircraft, D is the aerodynamic drag, k is the main wheel load distribution coefficient (aircraft parameter manual), L s is the aircraft lift (aircraft parameter manual), r is the tire radius, J is the main wheel moment of inertia (aircraft parameter manual), μ is the friction coefficient between the tire and the road (obtained from test), T is the braking torque (aircraft parameter manual); C D is the lift coefficient of the aircraft, C L is the aircraft's drag coefficient, m is the aircraft's (total) mass, g is the acceleration due to gravity, ρ is the air density, and S is the aircraft's wing area (actual parameter).

[0034] The slip rate is the difference between the grinding wheel linear speed and the rubber wheel linear speed divided by the grinding wheel linear speed. The brake is controlled based on the obtained slip rate. The test can be carried out under the same slip rate as the rubber wheel under test.

[0035] By formula Calculate the linear velocity V of the contact surface between the grinding wheel and the rubber wheel, where Ω is the angular velocity of the rubber wheel (rad / s); R e is the rolling radius of the rubber wheel (mm); V is the linear velocity of the contact surface between the grinding wheel and the rubber wheel (m / s).

[0036] n = V / πd is the target speed of the rubber wheel. The brake is controlled based on the target speed and the actual speed detected by the speed sensor (using a PID controller). The brake is a pneumatic disc brake that works with a brake disc. The pneumatic disc brake is connected to an air source. Different air pressures from the source produce varying clamping forces on the disc, resulting in varying slip rates between the rubber wheel and the grinding wheel. This allows for measuring the friction and wear performance of aircraft tires under varying slip rates.

[0037] The present invention provides a test device for aircraft tire landing impact friction and wear. A rubber wheel simulating an aircraft tire is fixedly connected to a rotating shaft using a specimen clamp. A grinding wheel simulating road testing is mounted on a servo motor using 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 adjustment block clamped to the impact support. The roll angle of the rubber wheel is adjusted by rotating an angle adjustment shaft clamped to the height adjustment block. The roll angle of the rubber wheel is adjusted by rotating a yaw adjustment shaft clamped to a connecting arm. The impact loading force is controlled by varying the weight of the loading weight. Rotating a reset handle activates a reset bar, which resets the stamping plate, and then the impact test is performed. At a set grinding wheel speed, the rubber wheel is driven to repeatedly impact the grinding wheel under set operating conditions, simulating the operating conditions of an aircraft tire landing. Sensors obtain corresponding test data, which can then be analyzed to obtain performance data for aircraft tires made from rubber wheels of different materials. The present invention has a simple structure and low cost, can simulate the landing impact friction and wear of aircraft tires simply and quickly, and the obtained friction and wear data has high accuracy, which can provide a reliable basis for the research and development of aircraft tire materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of the test device in the present invention.

[0039] Figure 2 It is a schematic diagram of the three-dimensional structure of the test device in the present invention.

[0040] Figure 3 It is a schematic diagram of the three-dimensional structure of the test device of the present invention after removing the grinding wheel friction device and the temperature collection device.

[0041] Figure 4 yes Figure 3 Schematic diagram of the three-dimensional structure after removing the supporting frame.

[0042] Figure 5 It is a schematic diagram of the three-dimensional structure of the loading and resetting device in the present invention.

[0043] Figure 6 Temperature rise history of the rubber wheel collected during the test.

[0044] Figure 7 Friction force history graph collected during the test. DETAILED DESCRIPTION

[0045] like Figure 1-5 The aircraft tire landing impact friction wear test device shown in the figure includes a support frame, which includes a support frame 1 and a table 20. A grinding wheel friction device is provided on the upper side of the table 20. The grinding wheel of the grinding wheel friction device is horizontally arranged and can rotate freely. The grinding wheel friction device includes a servo motor 15, a bearing seat 14, a grinding wheel 13 and a grinding wheel fastening device 12. Figure 1 、 Figure 2As can be seen, the servo motor 15 is fixedly mounted on the underside of the table 20, while the bearing seat 14 is positioned above it. A drive shaft is mounted within the bearing seat 14 via a bearing, the lower end of which is connected to the output shaft of the servo motor 15. The grinding wheel fastening device 12 shown features a lower fixing plate and an upper fixing plate on the upper portion of the drive shaft. The grinding wheel 13 is clamped to the lower fixing plate via a nut and the upper fixing plate. The servo motor achieves rotational motion at varying speeds, while the bearing seat withstands the radial impact load of the grinding wheel, as well as the axial friction and loading components. The grinding wheel fastening device secures the grinding wheel to the motor output shaft, rotating synchronously with it. An impact base plate 28 is provided on the table on the left side of the grinding wheel friction device. Two impact guide rails 21 are provided on the impact base plate 28, which are parallel to each other and arranged in the left and right directions. The two parallel impact guide rails 21 are linear guide rails. A left slider and a right slider are provided on the two impact guide rails 21 respectively. A stamping plate 16 is provided on the two left sliders. An impact load plate 34 is provided on the two right sliders. The stamping plate 16 and the impact load plate 34 are connected via a one-dimensional force sensor. The one-dimensional force sensor is an S-type tension and pressure sensor. A lateral force guide rail 25 is provided on the impact load plate 34 in the front and rear directions. An impact mounting plate is provided on the lateral force guide rail 25. The impact mounting plate 24 is provided on the impact mounting plate. The impact load plate 3 on the front side of the impact mounting plate 24 A sensor mounting seat is provided on the impact mounting plate 24. The sensor mounting seat is connected to the front side of the impact mounting plate 24 via a one-dimensional force sensor 29. The one-dimensional force sensor 2 is an S-type tension and pressure sensor. The impact mounting plate 24 is provided with an impact support 8 arranged vertically. A height adjustment block 9 is mounted on the impact support 8. The adjustment block 9 has a clamping hole. A tensioning notch is provided on the adjustment block 9 on one side of the clamping hole. An adjustment screw is provided on the adjustment block 9 to adjust the size of the tensioning notch. The impact support is positioned within the clamping hole. Tightening the adjustment screw secures the adjustment block 9 to the impact support 8. Loosening the adjustment screw widens the tensioning notch, allowing the adjustment block 9 to be adjusted in height on the impact support 8. The height of the height adjustment block 9 on the impact support 8 can be adjusted as needed. A tilt adjustment shaft 10 is mounted on the height adjustment block 9. A tilt adjustment arm 17 is provided on the tilt adjustment shaft 10. The tilt adjustment shaft 10 can rotate on the height adjustment block to adjust the angle between the tilt adjustment arm and the horizontal plane (the impact mounting plate). The inclination adjustment arm 17 is equipped with a connecting arm 171 extending forward and backward. A roll adjustment shaft extending left and right is mounted on this connecting arm 171. The connection structure between the connecting arm 171 and the roll adjustment shaft, and the connection structure between the inclination adjustment arm 17 and the roll adjustment shaft 10, are identical to the connection structure between the adjustment block and the impact strut. A mounting platform 23 is provided on the roll adjustment shaft opposite the grinding wheel friction device. A rotating shaft extending vertically through the mounting platform 23 is provided. A specimen holder 19 is mounted on the rotating shaft above the mounting platform 23. The structure of the specimen holder 19 is identical to that of the grinding wheel fastening device.A speed-measuring brake disc 33 is provided on the rotating shaft on the lower side of the mounting platform 23, and a speed sensor 32 is provided on one side of the mounting platform 23 to cooperate with the speed-measuring brake disc 33. As can be seen from the figure, the speed-measuring brake disc 33 has detection holes evenly distributed around the edge of the brake disc, and the speed sensor is a photoelectric beam sensor provided on the upper and lower sides of the brake disc to cooperate with the detection holes for detection. When the brake disc rotates, it affects the incident light on the sensor, thereby detecting the rotation speed information of the rubber wheel. On the other side of the mounting platform 23, a brake 22 is provided to cooperate with the speed-measuring brake disc 33. The brake 22 is a disc brake. An impact loading device and a loading and resetting device are provided. The impact loading device includes a loading weight 5, a transmission wire rope 31, and a guide pulley group 26. The loading weight 5 is suspended on one end of the transmission wire rope 31 below the table. After being guided by the guide pulley group 26, the other end of the transmission wire rope 31 is connected to the stamping plate 16. As can be seen from the figure, a connecting seat 40 is provided on the lower side of the stamping plate 16. The other end of the transmission wire rope 31 is connected to the connecting seat 40. The loading and resetting device is a reset handle 38 disposed horizontally and parallel to the stamping plate 16 (both are disposed horizontally) on the impact base plate 28 on the table below the stamping plate 16. One end of the reset handle 38 is connected to a dial motor 6 that drives its rotation, and the other end is provided with a reset dial wheel 30 on the upper side. A reset bar 39 that cooperates with the reset dial wheel 30 is provided on the lower side of the stamping plate 16 to the left of the reset dial wheel 30. As can be seen from the figure, the dial motor 6 is fixedly mounted on the lower side of the stamping plate 16. The dial motor 6 consists of a motor and a reducer. When the dial motor 6 is working, it drives the reset handle 38 to rotate. The reset dial wheel 30 cooperates with the reset bar 39 to move the stamping plate 16 to the left. A temperature acquisition device 11 is provided on the table. The temperature measuring head of the temperature acquisition device 11 is located on one side of the grinding wheel friction device. When in use, the temperature measuring head of the temperature acquisition device 11 is opposite to the contact point between the rubber wheel and the grinding wheel, and is used to collect the surface temperature of the rubber wheel specimen in real time during the experiment; the temperature acquisition device 11 uses a thermal imager.

[0046] The present invention is further improved in that a weight rack 2 is provided on the lower side of the table 20, and two guide slides 4 are vertically arranged up and down on the weight rack 2, and a weight plate 3 that can slide freely up and down is provided on the guide slide 4, and a weight penetrating rod 7 is vertically arranged up and down on the weight plate 3 between the two guide slides 4, and one end of the transmission wire rope 36 is connected to the weight plate.

[0047] A test method for aircraft tire landing impact friction and wear, characterized by comprising the following steps:

[0048] Step 1: Obtain the test parameters required based on the actual operating conditions of the aircraft being simulated (using the aircraft tire):

[0049] 1.1 Obtain the (average) maximum contact pressure P of the simulated aircraft tire during landing. Based on the load and air pressure specified in the aircraft tire standard, calculate the contact pressure P using finite element simulation or pressure blanket testing. Select a rubber tire with a diameter of 60-100mm and a thickness of 5-20mm. Calculate the required loading weight based on the maximum contact pressure P of the aircraft tire during landing.

[0050] 1.2. Obtain the maximum vertical speed v when the aircraft tire lands g , determine the maximum impact loading speed V of the reset dial load , V load =v g ;

[0051] According to the formula: Calculate the reset handle speed n b (i.e. the speed of the dial motor, n b =30000v load / πrsinβ),

[0052] Where n b is the speed of the reset handle (r / min); r is the length of the reset handle (the distance between the axis of the reset motor and the axis of the reset dial wheel) (mm); β is the angle (°) between the reset handle and the movement direction (forward and backward) of the impact mounting plate when the rubber wheel contacts the grinding wheel. β is usually a constant value between 30-90°.

[0053] 1.3. According to the horizontal linear speed v of the aircraft tire ground contact jd Calculate the rotational speed n of the grinding wheel;

[0054]

[0055] Where v jd is the horizontal linear velocity of the aircraft tire when landing (QAR data), n is the grinding wheel speed, π is the pi, d is the grinding wheel diameter, c yjd is the touchdown lift coefficient (QAR data), m is the aircraft (total) mass, g is the acceleration due to gravity, ρ is the air density, and S is the aircraft wing area (actual parameter).

[0056] 1.4. Obtain the rubber wheel's slip angle and roll angle (obtained from the aircraft's QAR data) based on the requirements of friction test research or the actual slip angle and roll angle of the aircraft tire during landing;

[0057] Step 2: Based on the parameters obtained in step 1, install the rubber wheel 18 for the test on the specimen holder 19; place the loading weight 5 on the weight plate 3, adjust the side slip angle and roll angle, and control the speed of the grinding wheel (so that its peripheral linear speed meets the requirements); control the rotation of the dial motor according to the reset handle speed n, and perform periodic loading to conduct the impact test;

[0058] Step 3: The one-dimensional force sensor 1 collects the impact load in real time, the one-dimensional force sensor 2 collects the 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 the friction interface in real time;

[0059] Step 4: Using the collected sensor data, the friction coefficient can be obtained by dividing the tangential force of the grinding wheel by the radial force of the grinding wheel (impact load). The wear amount can be obtained by the mass change of the rubber wheel before and after the weighing test. The wear morphology can be obtained by photographing the texture of the worn surface of the rubber wheel with an optical digital microscope. The temperature rise history and temperature field of the rubber on the friction surface can be obtained by collecting the results with a thermal imager. The quality of the aircraft tire tread material is evaluated based on the wear amount, wear morphology, temperature rise history and temperature field distribution. In the present invention, a tire footprint tester can be used to measure the (contact area measured, obtained) contact pressure of the rubber wheel under different loading forces (weight of the loading weight). The weight of the loading weight is divided by the tire footprint area to obtain the (average) contact pressure.

[0060] The v described in the present invention g =v A -ωLcosα;

[0061] Where, v A is the vertical velocity of the aircraft at the ADIRU, ω is the aircraft pitch change rate, L is the distance from the aircraft ADIRU to the main landing gear, and α is the aircraft pitch angle. A ,ω,L,α can all be obtained from the aircraft QAR data. According to the requirements of the civil aviation regulations for the vertical speed v in extreme working conditions such as forced landing g No more than 1.524m / s, when simulating the test of civil aviation tires, the maximum impact loading speed of the thumbwheel (V loadmax ) is 1.524m / s.

[0062] The present invention is further improved to calculate the aircraft tire slip rate S of the tire according to the braking parameters of the (simulated) aircraft tire during landing and the aircraft parameters. g

[0063]

[0064]

[0065]

[0066] Where: is the slip rate, is the first-order formula for slip rate, v jd is the landing taxiing speed of the aircraft, D is the aerodynamic drag, k is the main wheel load distribution coefficient (aircraft parameter manual), L s is the aircraft lift (aircraft parameter manual), r is the tire radius, J is the main wheel moment of inertia (aircraft parameter manual), μ is the friction coefficient between the tire and the road (obtained from test), T is the braking torque (aircraft parameter manual); C D is the lift coefficient of the aircraft, C L is the aircraft's drag coefficient, m is the aircraft's (total) mass, g is the acceleration due to gravity, ρ is the air density, and S is the aircraft's wing area (actual parameter).

[0067] The slip rate is the difference between the grinding wheel linear speed and the rubber wheel linear speed divided by the grinding wheel linear speed. The brake is controlled based on the obtained slip rate. The test can be carried out under the same slip rate as the rubber wheel under test.

[0068] By formula For the slip rate, modify the formula and calculate the linear velocity V of the contact surface between the grinding wheel and the rubber wheel.

[0069] Where, Ω is the angular velocity of the rubber wheel (rad / s); R e is the rolling radius of the rubber wheel (mm); V is the linear velocity of the contact surface between the grinding wheel and the rubber wheel (m / s).

[0070] n-πd / V is the target speed of the rubber wheel. The brake is controlled based on the target speed and the actual speed detected by the speed sensor (using a PID controller). The brake is a pneumatic disc brake that works with a brake disc. The pneumatic disc brake is connected to an air source. Different air pressures in the air source produce different clamping forces on the brake disc, resulting in different slip rates between the rubber wheel and the grinding wheel.

[0071] In the present invention, a tire footprint tester can be used to measure the contact pressure of a rubber wheel under different loading forces (load weights). The weight of the load weight is divided by the tire footprint area to obtain the (average) contact pressure (pressure per unit area, i.e., pressure intensity).

[0072] The present invention is described in the present invention v g =v A -ωLcosα;

[0073] Where, v A is the vertical velocity at the aircraft ADIRU, ω is the aircraft pitch change rate, L is the distance from the aircraft ADIRU to the main landing gear, and α is the aircraft pitch angle (α is the angle (°) between the reset handle and the direction of movement (fore-aft direction) of the impact mounting plate when the rubber wheel contacts the grinding wheel).A , ω, L, α can all be obtained from the aircraft QAR data. The upper limit theoretical data of the aircraft pitch angle α is 11 degrees. According to the requirements of the civil aviation regulations for the vertical speed v in extreme working conditions such as the forced landing process g No more than 1.524m / s, when simulating the test of civil aviation tires, the maximum impact loading speed of the thumbwheel (V loadmax ) is 1.524m / s.

[0074] The present invention can use the finite element simulation method to calculate the (average) maximum contact pressure P of the aircraft tire during landing based on the load and air pressure in the aircraft tire standard, or use a pressure blanket test to obtain the contact pressure P. When using the finite element method for calculation, a simulation model of the rubber wheel and the simulated road surface is established, specifically as follows: Figure 2 As shown in the figure; according to the GB / T9746-2013 standard, the maximum load and rated inflation pressure of the corresponding aircraft tire are obtained, and the corresponding contact area is measured using a tire footprint tester; the maximum contact pressure P of the aircraft tire is calculated from the ratio of the contact area measured by the tire (to the ground) under the maximum load of the aircraft tire; referring to the GB / T1689-2014 standard, to facilitate wear, the standard outer diameter of the rubber wheel is determined to be 80mm and the width is 18mm. The finite element method is used to establish a simulation model of the rubber wheel and the simulated road surface, and the contact pressure under different loads can be calculated. Based on this, the load F applied to the rubber wheel can be determined from the calculated maximum contact pressure P of the aircraft tire. Taking a safety factor of 1.5, the actual maximum loading weight (load) can be obtained.

[0075] Example 1

[0076] According to the national standard GB / T9746 for aircraft tires, taking the Boeing 737-800 aircraft as an example, the maximum load of the 46X17R20 main wheels is 20,870 kg. Combined with the actual contact area, the maximum contact pressure is approximately 2.5 MPa. Due to factors such as weather, aircraft tires will experience a certain degree of roll and yaw during landing. According to statistics, the maximum roll and yaw will not exceed 10 degrees.

[0077] The selected size is 80mm in diameter, 18mm in thickness, and the maximum contact area is 300mm. 2 The left and right (measured) rubber wheels were simulated and set with a side slip angle of 10° and a camber angle of 10°. The loading weight was calculated to be 650N. According to the formula Calculate the motor drive reset handle speed n b =86.8r / min (impact loading is performed at a speed of 86.8r / min);

[0078] According to the maximum landing speed of commercial aircraft such as Boeing 737-800 is 270km / h, the actual measured diameter of the grinding wheel is 400mm. According to the formula Calculate the grinding wheel speed n = 3582.8r / min

[0079] Step 2: Based on the parameters obtained in step 1, install the rubber wheel 18 for the test on the specimen holder 19; place the loading weight 5 on the weight plate 3, adjust the side slip angle and roll angle, and control the speed of the grinding wheel (so that its peripheral linear speed meets the requirements); control the rotation of the dial motor according to the reset handle speed n, and perform periodic loading to conduct the impact test;

[0080] Step 3: The one-dimensional force sensor 1 collects the impact load in real time, the one-dimensional force sensor 2 collects the 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 the friction interface in real time;

[0081] Step 4: Using the collected sensor data, the friction coefficient can be obtained by dividing the tangential force of the grinding wheel by the radial force of the grinding wheel (impact load). The wear amount can be obtained by the mass change of the rubber wheel before and after the weighing test. The wear morphology can be obtained by photographing the texture of the worn surface of the rubber wheel with an optical digital microscope. The temperature rise history and temperature field of the rubber on the friction surface can be obtained by collecting the results with a thermal imager. The quality of the aircraft tire tread material is evaluated based on the wear amount, wear morphology, temperature rise history and temperature field distribution. In the present invention, a tire footprint tester can be used to measure the (contact area measured, obtained) contact pressure of the rubber wheel under different loading forces (weight of the loading weight). The weight of the loading weight is divided by the tire footprint area to obtain the (average) contact pressure.

[0082] According to the device structure and test method of the present invention, the present invention can realize the impact friction of aircraft tires under different simulated actual landing conditions and high-speed friction under different side deviation and inclination angles, and obtain important parameters such as temperature distribution, friction force and temperature history curve, providing a basis for the design and evaluation of aircraft tire tread formulas, and also providing technical support for the development of high-performance aircraft tires. Figure 6 、 Figure 7 It can be seen that the present invention can specifically measure the impact friction data of rubber wheels of different materials under different working conditions. The data is accurate and reliable, and can provide specific data support for the design and evaluation of aircraft tire tread formulations.

Claims

1. A test device for aircraft tire landing impact friction and wear, comprising a support stand, the support stand comprising a support frame and a table, characterized in that A grinding wheel friction device is provided on the upper side of the table, and two impact guide rails are provided on the table on the left side of the grinding wheel friction device, and a left slider and a right slider are provided on the two impact guide rails respectively, and a stamping plate is provided on the two left sliders, and an impact load plate is provided on the two right sliders, and the stamping plate and the impact load plate are connected via a one-dimensional force sensor 1, and a lateral force guide rail is provided on the impact load plate, and an impact mounting plate is provided on the lateral force guide rail, and an impact mounting plate is provided on the impact mounting plate, and a sensor mounting seat is provided on the impact load plate on the front side of the impact mounting plate, and the sensor mounting seat is connected to the front side of the impact mounting plate via a one-dimensional force sensor 2; an impact pillar is provided on the impact pillar, and a height adjustment block is clamped on the impact pillar, and an inclination adjustment shaft set in the front and rear directions is clamped on the height adjustment block, and an inclination adjustment arm is clamped on the inclination adjustment shaft, and a connecting arm set in the front and rear directions is provided on the connecting arm. The clamp is provided with a lateral adjustment shaft arranged in the left and right directions, and a mounting platform is provided on the lateral adjustment shaft on the side opposite to the grinding wheel friction device, and a rotating shaft is provided on the mounting platform, and a specimen clamp is provided on the rotating shaft on the upper side of the mounting platform, and a speed measuring brake disc is provided on the rotating shaft on the lower side of the mounting platform, and a speed sensor and a brake matching the speed measuring brake disc are provided on one side of the mounting platform; an impact loading device and a loading and resetting device are provided, and the impact loading device includes a loading weight, a transmission wire rope and a guide pulley group, and the loading weight is suspended on one end of the transmission wire rope under the table, and the other end of the transmission wire rope is connected to the stamping plate after being guided by the pulley group; the loading and resetting device is provided with a reset handle on the table below the stamping plate, and a dial motor is provided at one end of the reset dial handle and a reset dial wheel is provided on the upper side of the other end, and a reset baffle matching with the reset dial wheel is provided on the lower side of the stamping plate on the left side of the reset dial wheel.

2. The aircraft tire landing impact friction and wear test device according to claim 1, characterized in that The 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 and wear test device according to claim 1, characterized in that The one-dimensional force sensor 1 and the one-dimensional force sensor 2 are S-type tension and pressure sensors.

4. The aircraft tire landing impact friction and wear test device according to claim 1, characterized in that A weight rack is provided on the lower side of the table, and two guide slides are provided on the weight rack. The guide slides are provided with a weight plate that can slide freely up and down. A weight penetrating rod is provided on the weight plate between the two guide slides, and one end of the transmission wire rope is connected to the weight plate.

5. The aircraft tire landing impact friction and wear test device according to claim 1, characterized in that The speed measuring brake disc has detection holes evenly distributed around the edge of the brake disc, and the speed measuring sensor is a photoelectric beam sensor provided on the upper and lower sides of the brake disc for detecting in conjunction with the detection holes.

6. The aircraft tire landing impact friction and wear test device according to claim 1, characterized in that A temperature collection device is provided on the table, and a temperature measuring head of the temperature collection device is located on one side of the grinding wheel friction device, and is used to collect the surface temperature of the rubber wheel specimen in real time during the experiment.

7. A test method for aircraft tire landing impact friction wear, characterized in that The steps include: Step 1: Obtain the test parameters required based on the actual operating conditions of the simulated aircraft: 1.1 Obtain the maximum contact pressure P of the aircraft tire during landing. Select a rubber wheel with a diameter of 50-200 mm and a thickness of 3-50 mm. Calculate the required loading weight based on the maximum contact pressure P of the aircraft tire during landing. 1.

2. Obtain the maximum vertical speed v when the aircraft tire lands g , determine the maximum impact loading speed V of the reset dial load , V load =v g ; According to the formula: Calculate the reset handle speed n b ; Where n b is the speed of the reset handle in r / min; r is the length of the reset handle; β is the angle between the reset handle and the direction of movement of the impact mounting plate when the rubber wheel contacts the grinding wheel; 1.

3. According to the horizontal linear speed v of the aircraft tire ground contact jd Calculate the rotation speed n of the grinding wheel; Where v jd is the horizontal linear velocity of the aircraft tire when landing, n is the grinding wheel speed, π is the pi, d is the grinding wheel diameter, c yjd is the touchdown lift coefficient, m is the aircraft mass, g is the acceleration due to gravity, ρ is the air density, and S is the aircraft wing area; 1.

4. Obtain the rubber wheel's slip angle and roll angle based on the requirements of friction test research or the actual slip angle and roll angle of the aircraft tire during landing; Step 2: Install the rubber wheel on the specimen fixture; place the loading weight on the weight plate, adjust the side tilt angle and side tilt angle, and control the speed of the grinding wheel; control the rotation of the dial motor according to the speed of the reset handle, periodically load, and perform the impact test; Step 3: The first one-dimensional force sensor collects the loading force in real time, the second one-dimensional force sensor collects the 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 the friction interface in real time; Step 4: Using the collected sensor data, the friction coefficient can be obtained by dividing the grinding wheel tangential force by the grinding wheel radial force. The wear amount can be obtained by the mass change of the rubber wheel before and after the weighing test. The wear morphology can be obtained by photographing the texture of the worn surface of the rubber wheel with an optical digital microscope. The temperature rise history and temperature field of the rubber on the friction surface can be obtained by collecting the results with a thermal imager. The quality of the aircraft tire tread material is evaluated based on the wear amount, wear morphology, temperature rise history, and temperature field distribution.

8. The method for testing aircraft tire landing impact friction and wear according to claim 7, characterized in that The v g =v A -ωLcosα; Where, v A is the vertical velocity of the aircraft at the ADIRU, ω is the aircraft pitch change rate, L is the distance from the aircraft ADIRU to the main landing gear, and α is the aircraft pitch angle.

9. The method for testing aircraft tire landing impact friction and wear according to claim 7, characterized in that Calculate the tire slip rate S according to the braking parameters of the aircraft tire during landing and the aircraft parameters. g Where: S g is the slip rate, is the first-order formula for slip rate, v jd is the landing taxiing speed of the aircraft, D is the aerodynamic drag, k is the main wheel load distribution coefficient, L s is the aircraft lift, r is the tire radius, J is the main wheel moment of inertia, μ is the friction coefficient between the tire and the road, and T is the braking torque; C D is the lift coefficient of the aircraft, C L is the aircraft's drag coefficient, m is the aircraft's mass, g is the acceleration due to gravity, ρ is the air density, and S is the aircraft's wing area; By formula Calculate the linear velocity V of the contact surface between the grinding wheel and the rubber wheel; where Ω is the angular velocity of the rubber wheel rad / s; R e is the rolling radius of the rubber wheel in mm; V is the linear velocity of the contact surface between the grinding wheel and the rubber wheel in m / s; n-πd / V is the target speed of the rubber wheel. The brake is controlled according to the target speed of the rubber wheel and the actual speed of the rubber wheel detected by the speed sensor.

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