Blade damage simulation method coupling hard object damage and corrosion test

Abstract

The invention provides a hard object damage and corrosion test coupled blade damage simulation method, which comprises the following steps of: performing a corrosion test on a metal test piece, and recording mass loss; calculating a mass loss mean value per unit surface area; obtaining a fitting equation of the mass loss per unit surface area and the corrosion time; calculating to obtain the corrosion time required for simulating the corrosion damage of the real blade by utilizing the fitting equation; performing a corrosion test on the simulated blade; carrying out a hard object damage test on the corroded simulation blade; and measuring and recording the size and the surface appearance of the blade damage notch. A test piece made of the same material as a real blade is used for carrying out a corrosion test to obtain a fitting equation between the corrosion time and the mass loss per unit surface area, so that the required corrosion time is obtained according to the mass loss per unit surface area of the real blade, and a simulated blade with the same corrosion degree as the real blade is obtained; the air cannon test system is used for carrying out a hard object damage test on the simulation blade, and the simulation blade which is damaged by a hard object and is closer to the real working condition is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engine blades, and in particular to a blade damage simulation method coupled with a hard object injury and a corrosion test. Background Art

[0002] Aircraft engines may be damaged by external hard objects under service conditions, such as screws, hail, gravel, sand and dust, etc. The damage may affect key engine components, such as blades and turbines, causing engine performance degradation or even failure. External object damage is one of the major hidden dangers to aircraft safety. Some standards refer to the damage caused by hard objects such as metal and sand hitting the engine as "foreign object damage" (FOD).

[0003] In order to ensure that the engines in service can still operate normally for a period of time after experiencing various types of damage, it is necessary to ensure that the material parameters and blade shape of the blades can still meet the fatigue limit requirements after damage at the beginning of the design. Since the blades in service may suffer random damage and the relative speed between the hard objects and the blades is very high, it is necessary to find a more realistic way to simulate the serious consequences of hard objects hitting the blades under laboratory conditions. At the same time, it is also necessary to consider the situation of the blades in service in the real working environment, such as the influence of factors such as oxidation corrosion. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a blade damage simulation method that can accurately simulate hard object damage and corrosion tests coupled under laboratory conditions.

[0005] Technical solution: A blade damage simulation method that couples hard object damage and corrosion tests, comprising the following steps:

[0006] (1) Multiple metal specimens made of the same material as the real blades were immersed in a corrosion solution at a constant temperature, and the mass loss at different corrosion times was recorded;

[0007] (2) Calculate the average mass loss per unit surface area of ​​each metal specimen under the same corrosion time;

[0008] (3) Using the corrosion time and the corresponding mean value of mass loss per unit surface area, the corresponding fitting equation is obtained;

[0009] (4) Measure the mass loss per unit surface area of ​​the actual blade and calculate the required corrosion time using the fitting equation;

[0010] (5) according to the corrosion time in step (4), immersing the simulated blade in the corrosion liquid to perform a corrosion simulation test;

[0011] (6) fixing the simulated blade corroded in step (5) in an air cannon test system using a fixing device, setting a hard object impact position, and conducting a hard object damage test;

[0012] (7) Measure and record the size and surface morphology of the blade damage notch.

[0013] Specifically, step (6) includes the following sub-steps:

[0014] (61) fixing the simulated blade on a holding device, and rotating the holding device so that the leading edge of the simulated blade and the barrel of the air cannon test system are at a predetermined incident angle;

[0015] (62) A hard object for testing is loaded into the gun tube, the pressure value of the air cannon test system is set, and the air cannon test system is controlled to push the hard object to hit the leading edge of the simulated blade.

[0016] Preferably, the cross-section of the gun barrel is square.

[0017] Preferably, step (61) further comprises: setting a point light source in the barrel of the gun barrel, forming a light spot at the muzzle of the gun barrel, and using the light spot to determine the impact position of the hard object.

[0018] Specifically, the step (7) includes: using a three-dimensional stereo microscope to measure the width and depth of the damage notch, and taking photos to record the damage morphology; and using a scanning electron microscope to observe and record the microscopic features of the damage notch.

[0019] Specifically, the fitting equation is:

[0020] Δm=a-be -ct

[0021] Where: Δm is the mass loss per unit surface area, e is the natural logarithm, t is the corrosion time, a, b, c are positive constants, which are related to the composition and concentration of the corrosion solution and the composition of the specimen.

[0022] Specifically, step (5) further includes: using an ultra-depth-of-field three-dimensional microscope system to measure and record the depth of the simulated blade surface after corrosion.

[0023] Specifically, the metal test piece is made of stainless steel, and in some embodiments, is 13Cr15Ni4Mo stainless steel.

[0024] Specifically, the etching solution contains Cl - In some embodiments, the corrosive solution is a dilute HCl solution.

[0025] Beneficial effect: Compared with the prior art, the present invention has the following significant effects: corrosion tests are carried out under laboratory conditions using standard test pieces made of the same material as actual blades to obtain a fitting equation between corrosion time and mass loss per unit surface area, thereby obtaining the corrosion time required under laboratory conditions based on the mass loss per unit surface area of ​​the actual blades, thereby obtaining simulated blades with the same degree of corrosion as the actual blades under laboratory conditions, and using an air cannon test system to carry out a hard object damage test on the simulated blades after corrosion to obtain simulated blades after hard object damage that are closer to actual working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the steps of the blade damage simulation method of coupled hard object damage and corrosion test in Example 1. DETAILED DESCRIPTION

[0027] The present invention is further explained below in conjunction with the accompanying drawings and specific implementation methods.

[0028] Example 1

[0029] In this embodiment, the selected corrosive liquid is HCl solution with a mass fraction of 3.5%, the materials used for the metal test piece and the simulated blade are 13Cr15Ni4Mo stainless steel, and the size of the metal test piece is 20mm×20mm×10mm.

[0030] Please refer to Figure 1 As shown, this embodiment provides a blade damage simulation method for coupling hard object damage and corrosion test, and the method includes the following steps:

[0031] (1) Six stainless steel specimens were completely immersed in the corrosive solution and maintained at a constant temperature of 40°C. The mass loss of each specimen was recorded at 24 h, 72 h, 120 h, 192 h and 240 h.

[0032] (2) Calculate the mass loss per unit surface area Δm of each stainless steel specimen at the above corrosion time, that is, the ratio of mass loss to surface area, and calculate the average of the mass loss per unit surface area Δm of the six metal specimens at the same corrosion time to obtain the data in Table 1 below.

[0033] Table 1

[0034]

[0035] (3) Using the corrosion time and the average value of the corresponding unit surface area mass loss Δm, the corresponding fitting equation is obtained:

[0036]

[0037] Where: Δm is the mass loss per unit surface area, and t is the corrosion time.

[0038] (4) Measure the mass loss per unit surface area of ​​the actual blade, Δm, and use the above fitting equation to calculate the required corrosion time.

[0039] (5) According to the corrosion time in step (4), the simulated blades are immersed in the corrosion liquid to perform a corrosion simulation test to obtain multiple simulated blades with the same corrosion degree as the real blades, and the depth of the simulated blade surface after corrosion is measured and recorded using an ultra-depth of field three-dimensional microscope system.

[0040] (6) Fixing the simulated blade corroded in step (5) in the air cannon test system by using a fixing device, setting the hard object impact position, and conducting a hard object damage test, specifically comprising the following steps:

[0041] (61) The simulated blade is fixed on the holding device by a clamp. In the present embodiment, the clamp is a turntable clamp, which can rotate 360° in the horizontal and vertical directions respectively. The clamp is fixed on the three-coordinate moving platform of the holding device so that it can move freely in three directions, so that the simulated blade can be impacted by hard objects at various positions and angles.

[0042] Rotate the turntable fixture to make the leading edge of the simulated blade and the barrel of the air cannon test system present a predetermined incident angle, and move the three-coordinate mobile platform back and forth along the direction of the barrel so that the leading edge is 2 to 3 cm away from the muzzle, leaving aiming space, set a point light source in the barrel of the barrel, form a light spot at the muzzle, and the center of the light spot is the impact position of the foreign object. Move the three-coordinate mobile platform so that the preset impact position is at the center of the light spot.

[0043] In this embodiment, the air gun barrel adopts a square gun barrel and a square bullet support which are different from those in conventional tests, so as to control the flight posture of irregular hard objects and achieve precise control of the hard object injury test.

[0044] (62) A hard object for testing is loaded into the barrel of the gun, the cylinder pressure is preset using the control system software, and the air cannon test system is controlled to accelerate the hard object and hit the leading edge of the simulated blade to cause impact damage.

[0045] (7) Use a three-dimensional stereo microscope and adjust the magnification (50 / 100 times) according to the field of view of the microscope to measure the width and depth of the damage notch and take photos to record the damage morphology; use a scanning electron microscope to observe and record the microscopic characteristics of the damage notch to provide data support for further analysis.

Claims

1. A blade damage simulation method coupling hard object damage and corrosion test, characterized in that: The following steps are involved: (1) Multiple metal specimens made of the same material as the real blades were immersed in a corrosion solution at a constant temperature, and the mass loss at different corrosion times was recorded; (2) Calculate the average mass loss per unit surface area of ​​each metal specimen under the same corrosion time; (3) Using the corrosion time and the corresponding mean value of mass loss per unit surface area, the corresponding fitting equation is obtained; (4) Measure the mass loss per unit surface area of ​​the actual blade and calculate the required corrosion time using the fitting equation; (5) according to the corrosion time in step (4), immersing the simulated blade in the corrosion liquid to perform a corrosion simulation test; (6) fixing the simulated blade corroded in step (5) in an air cannon test system using a fixing device, setting a hard object impact position, and conducting a hard object damage test; (7) Measure and record the size and surface morphology of the blade damage notch.

2. The blade damage simulation method according to claim 1, characterized in that: The step (6) comprises the following sub-steps: (61) fixing the simulated blade on a holding device, and rotating the holding device so that the leading edge of the simulated blade and the barrel of the air cannon test system are at a predetermined incident angle; (62) A hard object for testing is loaded into the gun tube, the pressure value of the air cannon test system is set, and the air cannon test system is controlled to push the hard object to hit the leading edge of the simulated blade.

3. The blade loss simulation method according to claim 2, characterized in that: The cross section of the gun barrel is square.

4. The blade loss simulation method according to claim 2, characterized in that: The step (61) further includes: arranging a point light source in the barrel of the gun barrel, forming a light spot at the muzzle of the gun barrel, and using the light spot to determine the impact position of the hard object.

5. The blade loss simulation method according to claim 1, characterized in that: The step (7) comprises: using a three-dimensional stereo microscope to measure the width and depth of the damage notch, and taking photos to record the damage morphology; and using a scanning electron microscope to observe and record the microscopic features of the damage notch.

6. The blade loss simulation method according to claim 1, characterized in that: The fitting equation is: Δm=a-be -ct Where: Δm is the mass loss per unit surface area, e is the natural logarithm, t is the corrosion time, and a, b, and c are positive constants.

7. The blade damage simulation method according to claim 1, characterized in that: The step (5) further includes: using an ultra-depth-of-field three-dimensional microscope system to measure and record the depth of the simulated blade surface after corrosion.

8. The blade damage simulation method according to claim 1, characterized in that: The metal test piece is made of stainless steel.

9. The blade damage simulation method according to claim 1, characterized in that: The etching solution is an aqueous solution containing Cl-.

10. The blade damage simulation method according to claim 9, characterized in that: The corrosive liquid is a dilute HCl solution.

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