Propeller blade bird strike test device and method

Abstract

The application discloses a propeller blade bird collision test device and method, and relates to the technical field of aircrafts.The device comprises a projectile launching system, a fixing system and a speed measuring system.The speed measuring system comprises a laser speed measuring module and a high-speed camera.The laser speed measuring module measures the speed of a bird projectile, and the high-speed camera photographs the flight and impact process of the bird projectile.The projectile launching system is an air cannon, and the projectile launching system is used for launching the bird projectile.The fixing system comprises a rack, and the rack fixes a test piece through a fixing tool.The test piece is a propeller blade or a simulated propeller blade.The application has high measurement precision, can accurately capture key data in the impact transient state, and provides reliable reference data for subsequent optimization of propeller anti-collision structures and calibration of simulation models.

Description

Technical Field

[0001] This invention relates to the field of aircraft technology, specifically to a propeller blade bird strike test device and method. Background Technology

[0002] Bird activity is dense in low-altitude flight areas, and high-speed rotating propellers are prone to bird strikes. The instantaneous impact force can cause the propeller blades to break and deform, which can lead to engine failure or even complete power failure, seriously threatening personnel safety. Therefore, the propeller's bird strike resistance is an important guarantee for aviation safety.

[0003] Existing bird strike testing systems lack sufficient measurement accuracy, failing to comprehensively and accurately capture critical transient impact data, and thus hindering structural optimization and simulation calibration. Therefore, there is an urgent need to optimize bird strike testing equipment and methods to improve safety and reduce R&D costs and risks. Summary of the Invention

[0004] To overcome the shortcomings of the prior art and solve at least one of the technical problems mentioned in the background art, the present invention provides a propeller blade bird strike test device and method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On one hand, the present invention provides a propeller blade bird strike test device, including a projectile launching system, a fixing system, and a velocity measuring system. The velocity measuring system includes a laser velocity measuring module and a high-speed camera. The laser velocity measuring module measures the velocity of the bird projectile, and the high-speed camera captures the bird projectile's flight and impact process.

[0007] The projectile launching system is an air cannon, and the projectile launching system is used to launch bird projectiles;

[0008] The fixing system includes a test bench, which fixes the test piece, which is a test propeller blade or a simulated propeller blade, using a fixing fixture.

[0009] Furthermore, three high-speed cameras were installed;

[0010] The first high-speed camera was used to record the bird strike process, including the flight trajectory before contact with the test specimen, the attitude during the impact, the location of the impact point, the time of contact with the test specimen, the bird's motion state after the impact, and the fragmentation and dispersion of the test specimen.

[0011] The second high-speed camera is used to record the bird strike process and monitor whether the propeller root breaks after the impact.

[0012] The third high-speed camera is perpendicular to the direction of the bird's flight and is used to assist in monitoring the bird's flight attitude and verifying its speed.

[0013] Secondly, the present invention provides a method of using a propeller blade bird strike testing device, comprising the following steps:

[0014] S1, Impact velocity calibration;

[0015] S2. Specimen posture adjustment:

[0016] S3, Formal Test:

[0017] S301. Confirm the predetermined impact point on the test specimen of the projectile launching system, and measure and record the weight of the impact object used.

[0018] S302. Place the bird projectile into the projectile launching system and install the test piece on the fixed fixture;

[0019] S303, calibrate bullet velocity and impact point;

[0020] S304. Inflate the pressure vessel of the projectile launching system with air, stop inflating when the pressure value is reached, activate the air release device to launch the bird projectile, and trigger the high-speed camera at the same time.

[0021] S305 After the bird projectile impacts the test specimen, first record and save all test data, then take a picture of the state of the test specimen after impact. The picture shows the test specimen number, impact point location, and impact speed information.

[0022] The impact velocity of the bird sling is recorded by a high-speed camera or velocity measurement module. If the sling penetrates, the remaining velocity is recorded. The process before and after the bird sling impact is also recorded by a high-speed camera.

[0023] S4. Evaluation of test results.

[0024] Furthermore, in S1, the pressure required for the test is determined based on the required bird shot and impact velocity, and live-fire is conducted. If the live-fire velocity deviates from the required velocity by more than ±2%, the pressure of the projectile launching system is adjusted and live-fire is conducted again until the velocity deviation is less than ±5%.

[0025] In S303, the bullet velocity and impact point are calibrated. The parameters of the equipment are set according to the parameters calibrated in S1 to make the bullet velocity deviation within ±2% and the impact point is calibrated.

[0026] In S304, the pressure vessel of the projectile launching system is inflated. Based on the calibration results of S1, an appropriate inflation pressure is selected. When the pressure value is reached, inflation is stopped, the air release device is activated to launch the bird projectile, and the high-speed camera is triggered at the same time.

[0027] Furthermore, in S4, the test specimen is subjected to visual inspection, blade stiffness testing, blade angle testing, and ultrasonic detection of blade delamination and internal damage.

[0028] For propeller test pieces intended to be mounted on the side of the fuselage, bird strikes must not produce high-energy fragments capable of penetrating the fuselage;

[0029] For the test propeller of the tension type intended to be installed in the nose, the fragments generated by the bird strike will not hit the fuselage and cause damage to the aircraft, so there is no need to conduct a fragment impact assessment.

[0030] Bird strike-induced propeller imbalance loads must not damage the engine or the aircraft.

[0031] Furthermore, in S302, strain gauges are pasted on the inner surface of the test specimen in the required direction. When pasting, air in the adhesive layer must be removed to ensure the adhesion and orientation accuracy of the adhesive layer.

[0032] In S305, the strain generated at each point of the test specimen during the impact process is recorded by a strain acquisition system.

[0033] Furthermore, it also includes step S5, determining whether the test is qualified;

[0034] If the difference between the center of the actual impact location and the geometric center of the test piece is less than 20 mm, and the off-axis angle of the bird strike does not exceed 5 degrees, the test is valid.

[0035] Furthermore, the impact data is derived using the following formula:

[0036] Impact speed for: ;

[0037] Bird strike angle for: , , , ;

[0038] in:

[0039] Impact point radius of leaf element: ;

[0040] Propeller speed (unit: revolutions per minute): RPM;

[0041] Aircraft speed: ;

[0042] Bird speed: ;

[0043] Bird speed relative to airplane: ;

[0044] Impact velocity (bird's standing velocity relative to the propeller blade element section): ;

[0045] Leaf element section station rotational tangential velocity: ;

[0046] Bird strike angle (angle between bird's flight path and leaf line): ;

[0047] Angle between the blade element chord and the propeller disk plane: ;

[0048] The angle between the bird's composite velocity and the propeller disk plane: .

[0049] Furthermore, the selection of the bird strike location is made using the following formula:

[0050] For the maximum blade root load caused by a bird strike, the blade root bending moment is evaluated using the bird strike momentum angular momentum: ;

[0051] Where m is the bird's weight and h is the height of the impact point relative to the rotor hub rim;

[0052] The maximum local impact damage caused by a bird strike is evaluated using the kinetic energy of the bird approaching the blade along the normal to the point of impact: ;

[0053] The impact energy at different locations on the propeller is calculated using the above formula, and the bird strike test is conducted at the point of maximum impact.

[0054] Compared with the prior art, the present invention has the following advantages:

[0055] 1. This invention has high measurement accuracy and can accurately capture key transient impact data, providing reliable reference data for subsequent propeller impact-resistant structure optimization and simulation model calibration.

[0056] 2. This invention can be used for sampling and testing of products to ensure that products meet safety standards. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the structure of a bird strike test device for a propeller blade according to the present invention.

[0058] Figure 2 This is a schematic diagram of the fixing system for fixing the propeller blades in this invention.

[0059] Figure 3 This is a schematic diagram of bird strike-related data for this invention. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Example 1:

[0062] Please see Figure 1 , Figure 2 This embodiment provides a propeller blade bird strike test device, including a projectile launching system, a fixing system, and a speed measuring system.

[0063] Furthermore, the projectile launching system is used to launch bird projectiles. The projectile launching system is an existing air gun, including a launching mechanism, a accumulator connected to the launching mechanism, an air compressor connected to the accumulator, a barrel provided in the launching mechanism, a discarding sabot provided at the end of the barrel, a sabot loaded in the launching mechanism, and a bird projectile placed in front of the sabot.

[0064] The compressor brings the pressure required for the test into the accumulator in a short time.

[0065] The pressure accumulator is configured with volume and working pressure based on the mass and impact velocity of the bird projectile.

[0066] The launching mechanism can be a manual, electric, or pneumatic device. The launching mechanism is leak-proof during inflation and ensures that all compressed air passes through rapidly and instantaneously during launch.

[0067] The inner wall of the gun barrel is smooth, and the inner diameter and length are selected based on the mass of the bird projectile, the velocity of the bird projectile, and the performance requirements of the air gun.

[0068] The sabot is a cylindrical barrel that fits well with the bird shell and the inner wall of the gun barrel, and the sabot can be made of foam plastic.

[0069] The discarding device separates the sabot from the bird bullet and prevents sabot debris from interfering with the velocity measurement system or damaging the test specimen upon impact.

[0070] Furthermore, the fixing system includes a test bench, which fixes the test piece, which is a test propeller blade or a simulated propeller blade, using fixing fixtures.

[0071] The test bench is provided with a test platform, which is a vertical plate with multiple fixing screw holes. The fixing fixture is an L-shaped angle steel. The vertical end of the fixing fixture is connected to the test platform through a flange, bolts, and nuts. The test piece is connected to the horizontal end of the test platform through a paddle clamp, flange, bolts, and nuts.

[0072] Specifically, the fixed fixture is inverted L-shaped after being connected to the test bench.

[0073] Specifically, a protective screen is provided around the projectile launching system, the fixing system, and the velocity measuring system.

[0074] Furthermore, the speed measurement system includes a laser speed measurement module and a high-speed camera; the laser speed measurement measures the speed of the bird projectile, and the high-speed camera captures the bird projectile's flight and impact process.

[0075] The laser velocity measurement module uses a high-speed laser measurement method to test the speed of the bird missile during its flight. The specific method is as follows:

[0076] Two light curtains with a distance of L are installed on the flight path of the bird projectile. The impact velocity is calculated by the time the laser beam is blocked by the bird projectile. The direction of the laser beam is perpendicular to the direction of the impacting object. The accuracy of the velocity measurement system should be within 1% of the impact velocity.

[0077] Measure the time TL it takes for the bird to fly over the two light curtains, and calculate the bird speed using the formula V=L / TL.

[0078] Specifically, to ensure the reliability and accuracy of the measurement, three sets of laser velocity measurement modules are installed. If one set of measurement is invalid, the average of the speeds measured by the other two sets is taken as the result; if all three sets are valid, the average of the speeds measured by the three sets is taken.

[0079] The high-speed camera recorded the entire bird strike test.

[0080] Specifically, three high-speed cameras are set up, with a resolution of megapixels and a frame rate of no less than 10,000 frames per second;

[0081] The first high-speed camera was used to record the bird strike process, including the flight trajectory before contact with the test specimen, the attitude during the impact, the location of the impact point, the time of contact with the test specimen, the bird's motion after the impact, and the fragmentation and dispersion of the test specimen.

[0082] The second high-speed camera is used to record the bird strike process and monitor whether the propeller root breaks after the impact.

[0083] The third high-speed camera is perpendicular to the direction of the bird's flight and is used to assist in monitoring the bird's flight attitude and verifying its speed.

[0084] Bird bullets are made using the following method:

[0085] Chickens were suffocated or slaughtered within 0.5 hours before the trial use. The chickens were weighed before packaging, and the accuracy of the weighing equipment used was at least 0.5‰ of the chicken's weight.

[0086] Packaging materials for bird bombs can include polyethylene film, cotton fabric, or nylon, etc.

[0087] The weight of the bird bullet meets the relevant provisions of GJB2464A-2020 and AC-35-AA-2021-35.36-R0.

[0088] Example 2:

[0089] Based on Example 1, this example provides a method for using a propeller blade bird strike testing device, including the following steps:

[0090] Assemble the bird strike test device for propeller blades as described in Example 1.

[0091] S1, Impact velocity calibration;

[0092] The required pressure for the test is determined based on the bird bullet and impact velocity required for the test, and live-fire is conducted. If the live-fire velocity deviates from the required velocity by more than ±2%, the pressure of the projectile launching system is adjusted and live-fire is conducted again until the projectile velocity deviation is less than ±5% before the formal test can be carried out.

[0093] S2. Specimen posture adjustment:

[0094] Adjust the bird strike and impact attitude required for the test until the attitude meets the designed bird strike requirements;

[0095] S3, Formal Test:

[0096] S301. Use methods such as lasers, mirrors, and levels to confirm the predetermined impact point on the test piece of the projectile launching system, and measure and record the weight of the impacting object used.

[0097] S302. Place the bird projectile into the projectile launching system and install a similar-sized simulated test piece on a fixed fixture;

[0098] S303. Calibrate the bullet velocity and impact point position. Set the equipment parameters according to the parameters calibrated in S1 to ensure that the bullet velocity deviation is within ±2% and calibrate the impact point position.

[0099] S304. Inflate the pressure vessel of the projectile launching system with air. Select an appropriate inflation pressure based on the calibration result of S1. Stop inflation when the pressure value is reached. Activate the air release device to launch the bird projectile and trigger the high-speed camera at the same time.

[0100] S305 After the bird projectile impacts the test specimen, first record and save all test data, then take a picture of the state of the test specimen after impact. The picture shows the test specimen number, impact point location, and impact speed information.

[0101] The impact velocity of the bird slingshot is recorded using a high-speed camera or velocity measurement module. If the slingshot penetrates the target, the remaining velocity is recorded. The process before and after the bird slingshot impact is also recorded using a high-speed camera.

[0102] S4. Evaluation of test results:

[0103] Visual inspection, blade stiffness testing, blade angle testing, and ultrasonic testing of blade delamination and internal damage were performed on the test specimens.

[0104] For propeller test pieces intended to be mounted on the side of the fuselage, bird strikes must not produce high-energy fragments capable of penetrating the fuselage;

[0105] For the thrust-type propeller test piece intended for installation in the nose, bird strike debris will not hit the fuselage and cause damage to the aircraft, so there is no need for debris impact assessment.

[0106] Bird strike-induced propeller imbalance loads must not damage the engine or the aircraft.

[0107] S5. Test pass / fail determination;

[0108] If the difference between the center of the actual impact location and the geometric center of the test piece is less than 20 mm, and the off-axis angle of the bird strike does not exceed 5 degrees, the test is valid.

[0109] Example 3:

[0110] In Example 2, if it is necessary to measure the strain of the test specimen during the impact, strain gauges are pasted on the inner surface of the test specimen in the required direction in S302. When pasting, the air in the adhesive layer must be removed to ensure the firmness of the adhesive layer and the accuracy of the direction.

[0111] In S305, the strain generated at each point of the test specimen during the impact process is recorded by a strain acquisition system.

[0112] Example 4:

[0113] Please see Figure 3 In Example 2, the impact data was obtained using the following formula:

[0114] Impact speed for: ;

[0115] Bird strike angle for: , , , ;

[0116] in:

[0117] Impact point radius of leaf element: ;

[0118] Propeller speed (unit: revolutions per minute): RPM;

[0119] Aircraft speed: ;

[0120] Bird speed: ;

[0121] Bird speed relative to airplane: ;

[0122] Impact velocity (bird's standing velocity relative to the propeller blade element section): ;

[0123] Leaf element section station rotational tangential velocity: ;

[0124] Bird strike angle (angle between bird's flight path and leaf line): ;

[0125] Angle between the blade element chord and the propeller disk plane: ;

[0126] The angle between the bird's composite velocity and the propeller disk plane: .

[0127] Furthermore, the selection of the bird strike location is made using the following formula:

[0128] For the maximum blade root load caused by a bird strike, the blade root bending moment is evaluated using the bird strike momentum angular momentum: ;

[0129] Where m is the bird's weight and h is the height of the impact point relative to the rotor hub rim;

[0130] The maximum local impact damage caused by a bird strike is evaluated using the kinetic energy of the bird approaching the blade along the normal to the point of impact: ;

[0131] The impact energy at different locations on the propeller is calculated using the above formula, and the bird strike test is conducted at the point of maximum impact.

[0132] All components not discussed in detail in this application, as well as the connection methods of these components, are well-known technologies in this field. They can be directly applied and will not be elaborated further.

[0133] In this invention, the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0134] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0135] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0136] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A propeller blade bird strike test device, comprising a projectile launching system, a fixing system, and a velocity measuring system, characterized in that, The speed measurement system includes a laser speed measurement module and a high-speed camera; the laser speed measurement module measures the speed of the bird projectile, and the high-speed camera captures the bird projectile's flight and impact process. The projectile launching system is an air cannon, and the projectile launching system is used to launch bird projectiles; The fixing system includes a test bench, which fixes the test piece, which is the blade of a test propeller or a simulated blade, using a fixing fixture.

2. The propeller blade bird strike test device according to claim 1, characterized in that, Three high-speed cameras were installed; The first high-speed camera was used to record the bird strike process, including the flight trajectory before contact with the test specimen, the attitude during the impact, the location of the impact point, the time of contact with the test specimen, the bird's motion state after the impact, and the fragmentation and dispersion of the test specimen. The second high-speed camera is used to record the bird strike process and monitor whether the propeller root breaks after the impact. The third high-speed camera is perpendicular to the direction of the bird's flight and is used to assist in monitoring the bird's flight attitude and verifying its speed.

3. A method of using a propeller blade bird strike test device, characterized in that, Using the propeller blade bird strike test apparatus according to claim 1 includes the following steps: S1, Impact velocity calibration; S2. Specimen posture adjustment: S3, Formal Test: S301. Confirm the predetermined impact point on the test specimen of the projectile launching system, and measure and record the weight of the impact object used. S302. Place the bird projectile into the projectile launching system and install the test piece on the fixed fixture; S303, calibrate bullet velocity and impact point; S304. Inflate the pressure vessel of the projectile launching system with air, stop inflating when the pressure value is reached, activate the air release device to launch the bird projectile, and trigger the high-speed camera at the same time. S305 After the bird projectile impacts the test specimen, first record and save all test data, then take a picture of the state of the test specimen after impact. The picture shows the test specimen number, impact point location, and impact speed information. The impact velocity of the bird sling is recorded by a high-speed camera or velocity measurement module. If the sling penetrates, the remaining velocity is recorded. The process before and after the bird sling impact is also recorded by a high-speed camera. S4. Evaluation of test results.

4. The propeller blade bird strike test device according to claim 3, characterized in that, In S1, the pressure required for the test is determined based on the required bird projectile and impact velocity, and live-fire is conducted. If the live-fire velocity deviates from the required velocity by more than ±2%, the pressure of the projectile launching system is adjusted and live-fire is conducted again until the projectile velocity deviation is less than ±5%. In S303, the bullet velocity and impact point are calibrated. The parameters of the equipment are set according to the parameters calibrated in S1 to make the bullet velocity deviation within ±2% and the impact point is calibrated. In S304, the pressure vessel of the projectile launching system is inflated. Based on the calibration results of S1, an appropriate inflation pressure is selected. When the pressure value is reached, inflation is stopped, the air release device is activated to launch the bird projectile, and the high-speed camera is triggered at the same time.

5. The propeller blade bird strike test device according to claim 3, characterized in that, In S4, the test specimen is subjected to visual inspection, blade stiffness testing, blade angle testing, and ultrasonic detection of blade delamination and internal damage. For propeller test pieces intended to be mounted on the side of the fuselage, bird strikes must not produce high-energy fragments capable of penetrating the fuselage; For the test propeller of the tension type intended to be installed in the nose, the fragments generated by the bird strike will not hit the fuselage and cause damage to the aircraft, so there is no need to conduct a fragment impact assessment. Bird strike-induced propeller imbalance loads must not damage the engine or the aircraft.

6. The propeller blade bird strike test device according to claim 3, characterized in that, In S302, strain gauges are pasted on the inner surface of the test specimen in the required direction. When pasting, air in the adhesive layer must be removed to ensure the adhesion and the accuracy of the orientation. In S305, the strain generated at each point of the test specimen during the impact process is recorded by a strain acquisition system.

7. The propeller blade bird strike test device according to claim 3, characterized in that, It also includes step S5, the determination of test pass rate; If the difference between the center of the actual impact location and the geometric center of the test piece is less than 20 mm, and the off-axis angle of the bird strike does not exceed 5 degrees, the test is valid.

8. The propeller blade bird strike test device according to claim 3, characterized in that, Impact data is derived using the following formula: Impact speed for: ; Bird strike angle for: , , , ; in: Impact point radius of leaf element: ; Propeller speed (unit: revolutions per minute): RPM; Aircraft speed: ; Bird speed: ; Bird speed relative to airplane: ; Impact velocity (bird's standing velocity relative to the propeller blade element section): ; Leaf element section station rotational tangential velocity: ; Bird strike angle (angle between bird's flight path and leaf line): ; Angle between the blade element chord and the propeller disk plane: ; The angle between the bird's composite velocity and the propeller disk plane: .

9. A propeller blade bird strike test device according to claim 8, characterized in that, The location of a bird strike is selected using the following formula: For the maximum blade root load caused by a bird strike, the blade root bending moment is evaluated using the bird strike momentum angular momentum: ; Where m is the bird's weight and h is the height of the impact point relative to the rotor hub rim; The maximum local impact damage caused by a bird strike is evaluated using the kinetic energy of the bird approaching the blade along the normal to the point of impact: ; The impact energy at different locations on the propeller is calculated using the above formula, and the bird strike test is conducted at the point of maximum impact.

Images