Method for determining anti-resonance polishing parameters of aero-engine blade

Abstract

The invention provides an aero-engine blade anti-resonance polishing parameter determination method, and relates to the technical field of aero-engine compressor blade manufacturing, and the method comprises the steps: firstly testing the inherent frequency of a blade, determining an initial polishing parameter according to the surface quality requirement of the blade, testing the excitation frequency of a polishing system, and determining the polishing parameter; when the excitation frequency is equal to the first-order inherent frequency to the fifth-order inherent frequency, whether the corresponding stress value is larger than 200 MPa or not is judged; if the corresponding stress value is larger than 200 MPa, it is indicated that resonance occurs under the vibration frequency of the order, the initial polishing parameters are adjusted, the stress value corresponding to the excitation frequency of each order is tested again, and whether resonance occurs or not is judged; and if the corresponding stress value is smaller than 200 MPa, resonance does not occur under the vibration frequency of the order, and the polishing parameters are adopted for machining. And the step is repeated until the excitation frequency is equal to the first-order to fifth-order inherent frequency in the machining process, and when the stress value is smaller than a set threshold value, the set of parameters are polishing parameters.

Description

Technical Field

[0001] The invention relates to the technical field of manufacturing aero-engine compressor blades, and in particular to a method for determining polishing parameters for anti-resonance of aero-engine blades. Background Art

[0002] The double-neck blade is the core component of the compressor of an aircraft engine. After the blade body is milled, abrasive belt polishing is often used to improve the surface quality. On the blade automation production line, the blade moves with the robot and the abrasive belt is fixed for polishing. Considering the rapid conversion of multiple stations, the double-neck blade can only be fixed on the robot's quick-change fixture by a quick-change fixture cantilever. When the robot cantilever clamps one end of the blade for polishing, if the polishing parameters are not properly selected, when the excitation frequency and the natural frequency of the polishing system are equivalent, resonance will occur, and fatigue crack sources and even macroscopic cracks will be generated at the blade journal, seriously affecting the processing quality and service life of the double-neck blade. The present invention introduces a vibration test when determining the polishing parameters to obtain the excitation frequency of the polishing system, so that the excitation frequency avoids the natural frequency of the blade, ensuring that no resonance will occur during processing under the selected polishing parameters, eliminating the hidden dangers of potential cracks in the polishing process, and improving the processing quality and service life of the blade. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a method for determining polishing parameters for anti-resonance of aircraft engine blades. When this method is used to polish double-journal blades, no resonance will be generated, crack sources and macro cracks will be avoided during blade processing, and the polishing quality and service life of the blades will be improved.

[0004] A method for determining polishing parameters for anti-resonance of an aero-engine blade comprises the following steps:

[0005] Step 1: Test the blade natural frequency;

[0006] The large end of the double-neck blade is fixed on the clamping robot, and the sensor side heads in the vertical and parallel directions of the blade body are attached to the free end of the blade, that is, the small end of the blade. The blade body is hammered with a hammer at multiple points multiple times using the hammering method to obtain the double-neck blade response function, and the first-order, second-order, third-order, fourth-order and fifth-order natural frequencies of the double-neck blade are analyzed and extracted.

[0007] The sensor is an acceleration sensor or a vibration sensor.

[0008] Step 2: Determine the initial polishing parameters according to the blade surface quality requirements and test the excitation frequency of the polishing system;

[0009] The polishing parameters include polishing linear speed and polishing pressure;

[0010] The polishing system refers to a processing system composed of a robot, a fixture, a blade, and a polishing tool.

[0011] Step 3: Determine polishing parameters; when the excitation frequency in step 2 is equal to the first to fifth order natural frequencies in step 1, determine whether the corresponding stress value is greater than 200 MPa;

[0012] If the corresponding stress value is greater than 200MPa, it means that resonance occurs at this order of vibration frequency. Adjust the initial polishing parameters and test the stress values ​​corresponding to each order of excitation frequency again to determine whether resonance occurs. If the corresponding stress value is less than 200MPa, it means that no resonance occurs at this order of vibration frequency. Use this set of polishing parameters for processing. Repeat this step until the excitation frequency during processing is equal to the first to fifth order natural frequencies, and the stress value is less than the set threshold. This set of parameters is the polishing parameters.

[0013] The beneficial effects of adopting the above technical solution are:

[0014] The present invention provides a method for determining polishing parameters for preventing resonance of aircraft engine blades. The method first determines the natural frequency of the blades, then selects polishing parameters, and then tests the excitation frequency of the polishing system to avoid the natural frequency of the blades, thereby ensuring that the double-journal blades will not resonate during polishing, avoiding potential crack sources and macro cracks during polishing, and improving the polishing quality and service life of the blades.

[0015] The blades processed by the polishing parameters determined by the present invention have good quality, low cost and high efficiency, which ensures that the blade shape meets the design requirements and the internal quality of the blade meets the use requirements, and truly achieves shape-property collaborative manufacturing. The invention has broad market demand and application prospects in the polishing of blades of aircraft engines, gas turbines, etc. and other weak rigid parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the double-journal blade structure of the present invention;

[0017] Among them, 1-large end journal, 2-blade body, 3-small end journal;

[0018] Figure 2 This is a schematic diagram of the position of the sensor attached to the blade small end in two directions parallel to the blade body and perpendicular to the blade body in the present invention;

[0019] In the figure, 4 is a sensor attached to the small end of the blade parallel to the blade body, 5 is a sensor attached to the small end of the blade perpendicular to the blade body;

[0020] Figure 3 A schematic diagram of the total frequency response function of a double-journal blade obtained by the present invention;

[0021] Figure 4The excitation frequency and stress magnitude measured by the given initial polishing parameters under the condition of resonance in the present invention;

[0022] Figure 5 The excitation frequency and stress magnitude are measured without resonance after the polishing parameters are adjusted in the present invention. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] A method for determining polishing parameters for anti-resonance of an aero-engine blade comprises the following steps:

[0025] Step 1: Test the blade natural frequency;

[0026] Fix the big end of the double-journal blade on the clamping robot, the big end journal 1, the blade body 2, and the small end journal 3 as shown in Figure 1 As shown, the clamping device in utility model patent 202021397427.7 is used in this embodiment. The sensor side heads in two directions perpendicular to the blade body and parallel to the blade body are attached to the free end of the blade, i.e., the small end of the blade. Figure 2 As shown, sensor 4 is attached to the blade end in parallel with the blade body, and sensor 5 is attached to the blade end in perpendicular to the blade body. The hammer method is used to hammer the blade body multiple times at multiple points to obtain the double-journal blade response function, such as Figure 3 As shown, the first, second, third, fourth and fifth order natural frequencies of the double-journal blade are analyzed and extracted, as shown in Table 1;

[0027] Table 1: The first, second, third, fourth and fifth order natural frequencies of the double-journal blade extracted in this embodiment;

[0028] Modal Order Natural frequency (Hz) Tier 1 148.00 Tier 2 292.00 Tier 3 533.50 Tier 4 1235.50 Tier 5 3018.00

[0029] The sensor is an acceleration sensor or a vibration sensor.

[0030] In this embodiment, the response function is measured by the hammer method, which is a commonly used technical means in the field. Specifically, one end of the sensor is connected to the measured part, and the other end is connected to the data acquisition device, and the response function is obtained by processing the data through a computer and special software;

[0031] Step 2: Determine the initial polishing parameters according to the blade surface quality requirements, and test the excitation frequency of the polishing system; in this embodiment, the polishing pressure is 1 bar, the polishing linear speed is 13.1 m / s, and the excitation frequency of the polishing system is obtained, such as Figure 4 shown.

[0032] The polishing parameters include polishing linear speed and polishing pressure;

[0033] The polishing system refers to a processing system composed of a robot, a fixture, a blade, and a polishing tool.

[0034] Step 3: Determine polishing parameters; when the excitation frequency in step 2 is equal to the first to fifth order natural frequencies in step 1, determine whether the corresponding stress value is greater than 200 MPa;

[0035] If the corresponding stress value is greater than 200MPa, it means that resonance occurs at this order of vibration frequency. Adjust the initial polishing parameters and test the stress values ​​corresponding to each order of excitation frequency again to determine whether resonance occurs. If the corresponding stress value is less than 200MPa, it means that no resonance occurs at this order of vibration frequency. Use this set of polishing parameters for processing. Repeat this step until the excitation frequency during processing is equal to the first to fifth order natural frequencies, and the stress value is less than the set threshold. This set of parameters is the polishing parameters.

[0036] according to Figure 4 When the excitation frequency is 160.394Hz, which is equivalent to the first-order natural frequency of 148Hz, the stress value is 288.87MPa, which is greater than 200MPa. Near the second-order, third-order, fourth-order and fifth-order natural frequencies, the stress values ​​are all less than 200MPa. It is finally determined that only the first-order resonance is induced. The initial polishing parameters are adjusted, the polishing pressure is adjusted to 1.5bar, and the polishing line speed remains unchanged at 13.1m / s. The excitation frequency and the corresponding stress value in the process are tested again. The test results are as follows Figure 5 As shown in the figure, it can be determined that near the first, second, third, fourth and fifth order natural frequencies, the maximum stress value is only 71.31Mpa, and the other stress values ​​are smaller. It is determined that no resonance is induced, so the polishing parameters of polishing pressure of 1.5bar and polishing linear speed of 13.1m / s are used for processing.

[0037] Finally, through fluorescence detection, no potential crack sources and macro cracks were found in the processed blades, and the quality was qualified.

[0038] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned inventive concept. For example, the above-mentioned features are replaced with the technical features with similar functions disclosed in the embodiments of the present disclosure (but not limited to) to form a technical solution.

Claims

1. A method for determining polishing parameters for anti-resonance of aircraft engine blades, characterized in that: The following steps are involved: Step 1: Test the blade natural frequency; Step 2: Determine the initial polishing parameters according to the blade surface quality requirements and test the excitation frequency of the polishing system; Step 3: Determine polishing parameters; when the excitation frequency in step 2 is equal to the first to fifth order natural frequencies in step 1, determine whether the corresponding stress value is greater than 200 MPa; If the corresponding stress value is greater than 200MPa, it means that resonance occurs at this order of vibration frequency. The initial polishing parameters are adjusted, and the stress values ​​corresponding to each order of excitation frequency are tested again to determine whether resonance occurs. If the corresponding stress value is less than 200MPa, it means that no resonance occurs at this order of vibration frequency. This set of polishing parameters is used for processing. Repeat this step until the excitation frequency during processing is equal to the first to fifth order natural frequencies, and the stress value is less than the set threshold. This set of parameters is the polishing parameters.

2. A method for determining polishing parameters for anti-resonance of aircraft engine blades according to claim 1, characterized in that: Step 1 is as follows: fix the large end of the double-neck blade on the clamping robot, stick the side heads of the sensors in the directions perpendicular to the blade body and parallel to the blade body at the free end of the blade, i.e. the small end of the blade, use the hammering method to hammer the blade body multiple times at multiple points, obtain the response function of the double-neck blade, and analyze and extract the first-order, second-order, third-order, fourth-order and fifth-order natural frequencies of the double-neck blade.

3. A method for determining polishing parameters for anti-resonance of aircraft engine blades according to claim 2, characterized in that: The sensor is an acceleration sensor or a vibration sensor.

4. A method for determining polishing parameters for anti-resonance of aircraft engine blades according to claim 1, characterized in that: The polishing parameters in step 2 include polishing linear speed and polishing pressure; The polishing system refers to a processing system composed of a robot, a fixture, a blade, and a polishing tool.

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