Aircraft engine accessory positive sine vibration endurance test time calculation method

Abstract

The application provides an aero-engine accessory sine vibration endurance test time calculation method, and belongs to the technical field of aero-engines. The method comprises the following steps: determining the structural parameters of an aero-engine and the range of high and low pressure rotating speeds; determining the load profile and vibration value of the engine vibration environment; determining the sine vibration fatigue frequency of the aero-engine accessory; determining the resonance frequency of the accessory product; obtaining the fixed frequency acceleration total equivalent test time of the resonance frequency point; obtaining the acceleration vibration scanning cycle test time; and determining the vibration endurance test time according to the fixed frequency acceleration total equivalent test time and the acceleration vibration scanning cycle test time. The method provided by the application solves the problem that the current sine vibration endurance time determination is not scientific and reasonable, and improves the effectiveness and accuracy of the vibration endurance test of the engine accessory.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aero-engine durability test, and particularly relates to a sine vibration durability test time calculation method for aero-engine accessories. BACKGROUND

[0002] The vibration environment is one of the working environments that the aero-engine will inevitably bear in its life cycle, and the accessory failure caused by vibration has occurred in aero-engines, which may cause dangerous failures in aero-engines. Therefore, before the accessory is assembled for the whole machine test, the vibration durability test shall be completed according to the relevant standards and requirements to verify the structural integrity of the product.

[0003] In the prior art, the calculation method of the sine vibration durability test time of the transport aircraft power device accessory is according to the requirements of GJB150.16A-2009 Military Equipment Laboratory Environmental Test Method Part 16: Vibration Test or the relevant requirements of HB5830.5-1984 Environmental Conditions and Test Methods for Onboard Equipment Vibration. On the basis of completing the 30-minute fixed frequency test, the product 500-hour life equivalent 1-hour vibration fatigue test is converted. However, the current sine vibration durability test method does not fully consider the actual working characteristics of the engine and the actual problem of vibration fatigue frequency, which leads to many accessories passing the test, but exposing a large number of problems in the engine installation and field test, and the essence is that the current vibration fatigue durability test method is insufficient for the product structural integrity examination and verification.

[0004] Therefore, the existing calculation method of the sine vibration durability test time of the accessory has the following shortcomings:

[0005] 1) The current vibration durability test only provides a 30-minute fixed frequency test, and the residence time of the resonance point is short, which leads to insufficient vibration fatigue test times of the product resonance point;

[0006] 2) Based on the product development experience, the sine vibration durability test time is determined according to the equivalent relationship of 500:1 (transport aircraft), without considering the actual working characteristics of the engine and the vibration fatigue damage, which leads to the determination of the sine vibration durability test time being unscientific and unreasonable;

[0007] 3) The sine vibration fatigue frequency and the vibration durability test time cannot be reasonably determined according to the actual working environment and fatigue damage of the product, which cannot effectively verify the structural integrity of the product, leading to frequent failures of the product after being delivered to the field. SUMMARY

[0008] The present application aims to provide a sine vibration durability test time calculation method for aero-engine accessories to solve or alleviate at least one problem in the background art.

[0009] The technical solution of the present application is: an aero-engine accessory sine vibration endurance test time calculation method, comprising:

[0010] determining the structural parameters of the aero-engine and the range of high and low pressure rotating speeds;

[0011] According to the vibration environment measurement data of the typical installation position of the engine and the proportion of each typical working state in the mission profile, the sine vibration load spectrum of the engine at different typical installation positions is calculated according to the relevant standard statistical method, and the sine vibration load spectrum includes the sine vibration magnitude;

[0012] determining the sine vibration fatigue number of the aero-engine accessory;

[0013] determining the sweep frequency range of the accessory, and performing three-axis resonance inspection on the accessory by sine sweep vibration with predetermined sweep frequency parameters within the sweep frequency range, so as to determine the resonance frequency of the accessory product;

[0014] determining the engine full-state working frequency characteristic and dividing the working frequency to obtain different frequency bands of the engine, determining the vibration fatigue number of the engine in different frequency bands, and calculating the fixed frequency acceleration total equivalent test time of the resonance frequency point according to the vibration fatigue damage equivalence principle;

[0015] The determination of the vibration sweep cycle number is mainly based on the total fatigue number of the vibration endurance test minus the vibration fatigue number of the resonance point, so as to obtain the remaining vibration sweep cycle number, and the acceleration vibration sweep cycle test time is obtained according to the conversion relationship between the vibration sweep cycle number and the vibration sweep cycle time;

[0016] determining the vibration endurance test time according to the fixed frequency acceleration total equivalent test time and the acceleration vibration sweep cycle test time.

[0017] Further, the typical installation position of the engine includes the engine fan case, the core engine case, the turbine rear case and the accessory case.

[0018] Further, the sine vibration fatigue number of the aero-engine accessory is not less than 10 9 times.

[0019] Further, the sweep frequency range of the accessory is 10Hz-2500Hz.

[0020] Further, the predetermined sweep frequency parameters are:

[0021] sweeping within the sweep frequency range of 15Hz-40Hz at a sweep rate of amplitude 0.254mm not more than 1.0 octave / minute;

[0022] The sweep frequency is performed at a sweep rate of 2g acceleration not exceeding 1.0 octave / minute above the sweep range of 40Hz.

[0023] Further, the process of determining the fixed frequency acceleration total equivalent test time of the resonance frequency point is:

[0024] The engine full state working frequency characteristic is determined and the working frequency is divided:

[0025] The vibration environment of the full state of the typical installation position of the aero-engine is tested, and the vibration environment characteristics of the typical installation position of the engine are obtained, including the low-pressure rotor fundamental frequency and harmonic component, the high-pressure rotor fundamental frequency and harmonic component, and the low-pressure rotor fan aerodynamic excitation component. The division of the full state working frequency is as follows:

[0026] 1) The low-pressure rotor speed base frequency and 2 times frequency reflect the low-pressure rotor unbalance and harmonic component;

[0027] 2) The high-pressure rotor speed base frequency and 2 times frequency reflect the high-pressure rotor unbalance and harmonic component;

[0028] 3) The low-pressure rotor fan blade frequency reflects the vibration value of the fan aerodynamic excitation;

[0029] 4) Other frequency ranges reflect the vibration values of engine aerodynamic / combustion / mechanical noise, etc.;

[0030] The determined vibration fatigue number of the engine in different frequency bands is:

[0031] 1) The low-pressure rotor speed base frequency and 2 times frequency, the resonance point frequency in the frequency band range is subjected to at least 10 6 times of fixed frequency test;

[0032] 2) The high-pressure rotor base frequency and 2 times frequency, the resonance point frequency in the frequency band range is subjected to at least 10 7 times of fixed frequency test;

[0033] 3) The low-pressure rotor fan blade frequency, the resonance point frequency in the frequency band range is subjected to at least 3×10 7 times of fixed frequency test;

[0034] 4) Other frequency ranges, the resonance point frequency in the frequency band range is subjected to at least 3×10 7 times of fixed frequency test;

[0035] The fixed frequency acceleration total equivalent test time is calculated:

[0036]

[0037] T 固定频率等效时间The equivalent time of the fixed frequency acceleration equivalent test;

[0038] F 共振频率 The resonance frequency of the accessory product;

[0039] g f The vibration value of the resonance frequency point of the conventional vibration load spectrum;

[0040] g max The maximum vibration value of the frequency range where the resonance frequency point is located;

[0041] N 频率次数 The vibration fatigue number of the resonance frequency point;

[0042] b is the material coefficient;

[0043] The total equivalent time of the fixed frequency is:

[0044]

[0045] Further, the response output vibration value of the accessory product at the fixed frequency point during the fixed frequency test does not exceed the vibration limit value, and the vibration limit value G satisfies:

[0046] G = 10.0 × (1.0 + 25.26 × (H / L) 2 -8.42 × (H / L) 3 )

[0047] Where H is the vertical height from the accessory installation platform to the acquisition sensor; L is the vertical height from the vibration table to the acquisition sensor.

[0048] Further, the process of obtaining the acceleration vibration scanning cycle test time includes:

[0049] Performing a sine scanning cycle test between the upper and lower frequencies in the frequency scanning range, each scanning cycle time is predetermined hours, and obtaining the fatigue number N 扫描 of a single sine vibration scanning:

[0050]

[0051] Where: f H is the upper limit frequency, f L is the lower limit frequency; t is the single scanning cycle time;

[0052] Determine the scanning cycle number n of the sine vibration:

[0053]

[0054] Where: N 总 is the total number of one-way vibration fatigue; N 扫描Fatigue number of single scanning cycle; n is scanning cycle number; N1 is vibration fatigue number of low pressure base frequency and multiple frequency; N2 is vibration fatigue number of high pressure base frequency and 2 multiple frequency; N3 is fan rotor blade multiple frequency vibration fatigue number; N4 is vibration fatigue number of engine vibration characteristic; A is frequency point number of fixed frequency test in low pressure rotor base frequency and multiple frequency range; B is frequency point number of fixed frequency test in high pressure rotor base frequency and multiple frequency range; C is frequency point number of fixed frequency test in high pressure multiple frequency range; D is frequency point number of fixed frequency test in other frequency range;

[0055] Scanning cycle time: T is calculated 扫描循环时间 = t x n;

[0056] According to the vibration damage equivalent principle, the accelerated scanning cycle equivalent time is calculated:

[0057]

[0058] In the formula, alpha is a load amplification coefficient.

[0059] Further, the vibration endurance test time satisfies:

[0060] T 总时间 = T 固定频率总等效时间 + T 加速扫描循环等效时间 .

[0061] The method provided in the application has the following advantages compared with the prior art:

[0062] 1) The engine accessory sinusoidal vibration endurance test time calculation method and working process are established, the sinusoidal vibration endurance test time calculation method is improved, and the method is suitable for sinusoidal vibration endurance test time calculation of various types of turbojet and turbofan aircraft engines, improves the effectiveness and accuracy of the test, and has wide applicability;

[0063] 2) The sinusoidal vibration fixed frequency acceleration equivalent time calculation method, fixed frequency response limit control method, sinusoidal vibration scanning cycle number and acceleration equivalent test time calculation method, and vibration endurance test acceleration time determination method are proposed, which solves the problem of unscientific and unreasonable determination of current sinusoidal vibration endurance time, and improves the effectiveness and accuracy of engine accessory vibration endurance test;

[0064] 3) The sinusoidal vibration endurance test time calculation method suitable for aircraft engine accessories is formed, the effective verification of the fatigue resistance of the product is realized, the test time is significantly shortened, and the test efficiency is high, which provides technical support for the design and improvement of the accessory product. BRIEF DESCRIPTION OF DRAWINGS

[0065] In order to more clearly illustrate the technical solutions provided by the present application, the accompanying drawings will be briefly introduced. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0066] Figure 1 The flow chart of the method for calculating the accessory sine vibration endurance test time of the engine.

[0067] Figure 2 The engine core casing vibration load spectrum of an embodiment of the present application.

[0068] Figure 3 The schematic diagram of parameters H and L in the method for calculating the engine accessory fixed frequency point response limit value in the present application. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the embodiments of the present application will be described in more detail below with the accompanying drawings of the embodiments of the present application.

[0070] The present application aims to provide a method for calculating the accessory sine vibration endurance test time of an aero-engine, so as to realize sufficient and effective verification of the structural integrity of the accessory product, solve the technical problems of insufficient fixed frequency test number and insufficient accuracy of the endurance test time determination in the existing sine vibration fatigue test, and at the same time provide a more efficient and accurate method for calculating the accessory sine vibration endurance test time, so as to realize sufficient and effective verification of the structural integrity of the product.

[0071] As shown in Figure 1 The method for calculating the accessory sine vibration endurance test time of the aero-engine provided by the present application includes the following steps:

[0072] Step S1, determining the engine structure parameters and high and low pressure rotating speeds:

[0073] This embodiment of the present application takes a certain high-bypass-ratio turbofan engine as an example for illustrating the transport aircraft power device, the high and low pressure rotor rotating speeds of the turbofan engine in all states are shown in Table 1, wherein the rotating speed of the low pressure rotor ranges from 0 to 4500 r / min, the high pressure rotating speed ranges from 9000 to 15000 r / min, and the engine structure parameters include the number of fan rotor blades, which is 30 in this embodiment.

[0074] Table 1: Engine high and low pressure operating rotating speeds in all states (unit: r / min)

[0075]

[0076] Step S2, determining the engine vibration environment load profile and vibration value:

[0077] According to the vibration environment measurement data of typical installation positions of the engine and the proportion of each typical working state in the mission profile, the sinusoidal vibration load spectrum of the engine in different typical installation positions is calculated according to the statistical method of GJB Z126-99 Vibration, Impact Environment Measurement Data Induction Method. The typical installation positions of the engine include the engine fan case, the core engine case, the turbine rear case and the accessory case, etc.

[0078] For example, in this embodiment of the application, the calculated sinusoidal vibration magnitudes of the above-mentioned typical installation positions of the engine (the engine fan case, the core engine case, the turbine rear case and the accessory case) are 100g, 30g, 20g and 10g respectively, as shown in Figure 2 Fig. 3 shows the vibration load spectrum of the core engine case installation position in this embodiment.

[0079] Step S3, determining the sinusoidal vibration fatigue number:

[0080] With the continuous improvement of the fatigue limit of materials, according to the requirements of MIL-HDBK-1783B Structure Integrity Outline, in order to fully examine and verify the high-cycle fatigue resistance of the accessory product, the vibration fatigue number of the aero-engine accessory is determined to be not less than 10 9 times.

[0081] In the following embodiments of the application, the vibration fatigue number N 总 of the aero-engine accessory is taken as 10 9 times for calculation.

[0082] Step S4, determining the resonance frequency of the accessory, the process includes:

[0083] Determining the sweep frequency range of the accessory, performing three-axis resonance check of the sinusoidal sweep vibration of the accessory according to the sweep frequency range and sweep frequency parameters of the accessory, and determining the resonance frequency of the accessory product, which mainly examines the high-cycle fatigue resistance of the resonance point.

[0084] Among them, for the sweep frequency range of the accessory: since the mechanical structure product is not sensitive to the frequency below 10Hz, and considering the aerodynamic excitation of the engine blade and the upper limit of the frequency that can be reached by the actual vibration table, the lowest frequency of the accessory vibration durability test is determined to be 10Hz, and the highest frequency is 2500Hz.

[0085] For the resonant frequency of the accessory: the resonant frequencies of the accessory product are determined by performing a three-axis (axial, circumferential, and radial) resonant check with a sinusoidal sweep vibration at an amplitude of 0.254 mm (15-40 Hz) or an acceleration of 2 g (above 40 Hz) at a scan rate of no more than 1.0 octave / minute in the range of 10 Hz-2500 Hz. The resonant frequency is defined as any frequency at which the amplification factor (the ratio of the maximum output amplitude to the input amplitude) exceeds 2 in any direction.

[0086] For example, in this embodiment of the present application, an actuator is installed on the outer surface of the engine core casing, and is mainly used to adjust the adjustment angle of the adjustable stator blades of the high-pressure compressor to prevent the engine from surging. According to the resonant frequency determination method described above, the resonant point frequencies and vibration values of the actuator in three directions are obtained as shown in Table 2.

[0087] Table 2 Resonant point frequencies and vibration values of the actuator

[0088]

[0089]

[0090] Step S5, determining the resonant point acceleration equivalent test time:

[0091] The engine full-state working frequency characteristic is determined, and the engine is divided into different frequency bands according to the frequency, the vibration fatigue number of the engine in different frequency bands is determined, and the resonant frequency point acceleration equivalent test time is calculated according to the vibration fatigue damage equivalent principle. The specific process includes:

[0092] Step S51, determining the engine full-state frequency characteristic: the vibration environment of the full state (mainly including the typical working states of ground slow speed, air slow speed, landing slow speed, approach slow speed, maximum cruising, maximum climbing, maximum continuous, maximum take-off, etc.) of the typical installation position of the aero-engine is tested to obtain the vibration environment characteristics of the typical installation position of the engine, the low-pressure rotor fundamental frequency and harmonic component, the high-pressure rotor fundamental frequency and harmonic component, and the low-pressure rotor fan aerodynamic excitation is the main component. Therefore, the full-state frequency division is as follows:

[0093] 1) The low-pressure rotor speed base frequency and 2 times the frequency, reflecting the low-pressure rotor imbalance and harmonic component;

[0094] 2) The high-pressure rotor speed base frequency and 2 times the frequency, reflecting the high-pressure rotor imbalance and harmonic component;

[0095] 3) The low-pressure rotor fan blade frequency, reflecting the vibration value of the fan aerodynamic excitation;

[0096] 4) Other frequency ranges, reflecting the vibration values of engine aerodynamic / combustion / mechanical noise, etc.

[0097] Step S52, determine the engine different frequency band vibration fatigue frequency: combined with the actual working state of the accessory product, determine the different frequency band vibration fatigue frequency, the process is as follows:

[0098] 1) low pressure rotor speed base frequency and 2 times frequency, resonance point frequency in the range of this frequency band at least 10 6 Fixed frequency test;

[0099] 2) high pressure rotor base frequency and 2 times frequency, resonance point frequency in the range of this frequency band at least 10 7 Fixed frequency test;

[0100] 3) low pressure rotor fan blade frequency, resonance point frequency in the range of this frequency band at least 3x10 7 Fixed frequency test;

[0101] 4) other frequency range, resonance point frequency in the range of this frequency band at least 3x10 7 Fixed frequency test.

[0102] Step S53, determine the fixed frequency acceleration equivalent time: according to the principle of vibration fatigue damage equivalent, the low vibration value of the resonance point frequency fixed frequency test time equivalent conversion into the equivalent duration of the maximum vibration value of the frequency band, according to formula 1 to calculate the fixed frequency acceleration equivalent time:

[0103]

[0104] In the formula: T 固定频率等效时间 The equivalent time of fixed frequency acceleration equivalent test;

[0105] F 共振频率 The resonance frequency of the accessory product;

[0106] g f The vibration value of the resonance frequency point of the conventional vibration load spectrum;

[0107] g max The maximum vibration value of the frequency band where the resonance frequency point is located;

[0108] N 频率次数 The vibration fatigue frequency of the resonance frequency point;

[0109] b is the material coefficient, which can be obtained by drawing the S-N curve of the material fatigue test, generally the value range is 3-25.

[0110] The fixed frequency acceleration equivalent time of different fixed frequency points is summed up to get the total fixed frequency equivalent time:

[0111] In the present application, the response output value of the fixed frequency point is controlled to not exceed the vibration limiting value G calculated by the following formula during the fixed frequency test of the accessory product, so as to ensure the effectiveness and safety of the test results:

[0112] G = 10.0 x (1.0 + 25.26 x (H / L) 2 - 8.42 x (H / L) 3 )

[0113] Wherein, H is the vertical height from the accessory mounting platform to the collection sensor (unit: mm); L is the vertical height from the vibration table to the collection sensor (unit: mm), as shown in Figure 3 .

[0114] For example, in the embodiment of the present application, according to the resonance frequency point acceleration equivalent test time calculation method and criterion of the above steps, the engine frequency band division and fatigue number determined according to the upper and lower limits of the full state high and low pressure rotor working speed of the engine in Table 1 are shown in Table 3. At the same time, according to the fatigue test results of the actuator material, the material coefficient b = 4.8 is obtained, and according to the calculation method of formula 1, the equivalent duration of the maximum vibration value of the frequency band in which the resonance point frequency of the X direction in Table 3 is equivalent to the low vibration value is seen in formula 3- formula 6. Under the condition of no acceleration, the test time of the resonance frequency point is 110283.1 seconds according to formula 7; the acceleration equivalent time of different fixed frequency points is summed up, see formula 8, and the total equivalent time of the actuator X direction is 30381.5 seconds, which significantly shortens the test time and improves the test efficiency.

[0115] Table 3 Vibration fatigue number based on engine frequency characteristics

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123] Step S6, determine the remaining scan cycle number and the acceleration equivalent test time:

[0124] The determination of the vibration scanning cycle number is mainly based on the total number of vibration fatigue of the vibration durability test minus the vibration fatigue number of the resonance point, so as to obtain the remaining vibration scanning cycle number, and the acceleration vibration scanning cycle test time is obtained according to the conversion relationship between the vibration scanning cycle number and the vibration scanning cycle time.

[0125] Step S61, determining the vibration scanning cycle test method: performing 10Hz to 2500Hz to 10Hz sinusoidal scanning cycle test between the determined upper and lower limit frequencies, each scanning cycle time is 2 hours, the fatigue number N of single sinusoidal vibration scanning 扫描 The calculation method is shown in formula 9:

[0126]

[0127] In the formula, f H is the upper limit frequency, f L is the lower limit frequency, and the unit is Hz; t is the single scanning cycle time, and the unit is second.

[0128] Step S62, determining the vibration scanning cycle number: the calculation formula of the scanning cycle number n of the sinusoidal vibration is shown in formula 10:

[0129]

[0130] In the formula, N 总 is the total number of single direction vibration fatigue; N 扫描 is the fatigue number of single scanning cycle; n is the scanning cycle number; N1 is the vibration fatigue number of the low-pressure fundamental frequency and the multiple frequency; N2 is the vibration fatigue number of the high-pressure fundamental frequency and the 2 multiple frequency; N3 is the vibration fatigue number of the fan rotor blade multiple frequency; N4 is the vibration fatigue number of the vibration characteristics of the engine aerodynamic / combustion / mechanical noise; A is the number of frequency points of the fixed frequency test in the low-pressure rotor fundamental frequency and multiple frequency range; B is the number of frequency points of the fixed frequency test in the high-pressure rotor fundamental frequency and multiple frequency range; C is the number of frequency points of the fixed frequency test in the high-pressure multiple frequency range. D is the number of frequency points of the fixed frequency test in other frequency ranges. Generally, A, B, C and D are less than or equal to 4.

[0131] Step S63, determining the scanning cycle time: the scanning cycle time is calculated by formula 11, which is equal to the scanning cycle number n multiplied by the single scanning cycle time t:

[0132] T 扫描循环时间 =t×n (11)

[0133] Step S64, determining the acceleration scanning cycle time: according to the vibration damage equivalent principle, the acceleration scanning cycle equivalent time T 加速扫描循环等效时间 is calculated by formula 12:

[0134]

[0135] In the formula, a is a load amplification factor, generally not more than 2.5, and 1.6 is recommended.

[0136] For example, in this embodiment of the present application, the sine vibration fatigue number N 扫描 , the equivalent sine vibration fatigue number N 扫描 = 3.25 x 10 6 ; according to the calculation method of formula 10, the calculation result of the residual scanning cycle number of the X-direction actuator is shown in formula 13, and the residual scanning cycle number of the actuator is obtained as 277 cycles; at the same time, according to the calculation method of formula 11, the calculation result of the scanning cycle time is shown in formula 14, and the scanning cycle time is obtained as 554 hours; according to the calculation method of formula 12, the calculation result of the accelerated scanning cycle equivalent time is shown in formula 15, and the final accelerated scanning cycle equivalent time is determined as 58.04 hours.

[0137]

[0138] T 扫描循环时间 = t x n = 2 x 277 = 554 hours (14)

[0139]

[0140] Step 7: Determine the vibration endurance test time, and the calculation method is shown in the following formula:

[0141]

[0142] In the formula, T 总时间 is the total test time of the vibration endurance test, and m is the number of resonance points of the single-direction accessory product; m = A + B + C + D.

[0143] For example, in this embodiment of the present application, according to the calculation method of the above formula, the total time of the vibration endurance test time is calculated as 66.48 hours, which is far lower than the conventional vibration load spectrum of 584.63 hours, and the test time can be significantly shortened under the condition of ensuring the vibration fatigue test number of the accessory product, and the test efficiency is improved.

[0144]

[0145] Compared with the prior art, the method provided by the present application has the following advantages:

[0146] 1) The engine accessory sinusoidal vibration durability test time calculation method and workflow are established, the accessory sinusoidal vibration durability test time calculation method is improved, and the method is suitable for various types of turbojet and turbofan engine accessory sinusoidal vibration durability test time calculation, which improves the effectiveness and accuracy of the test, and has wide applicability;

[0147] 2) The sinusoidal vibration fixed frequency acceleration equivalent time calculation method, fixed frequency response limit control method, sinusoidal vibration scanning cycle number and acceleration equivalent test time calculation method, and vibration durability test acceleration time determination method are proposed, which solves the problem of unscientific and unreasonable determination of current sinusoidal vibration durability time, and improves the effectiveness and accuracy of engine accessory vibration durability test;

[0148] 3) The sinusoidal vibration durability test time calculation method suitable for aero-engine accessories is formed, which realizes effective verification of the fatigue resistance of the product, significantly shortens the test time, and has the characteristics of high test efficiency, and provides technical support for the design and improvement of the accessory product.

[0149] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An aeroengine attachment sinusoidal vibration endurance test time calculation method, characterized by, The method comprises the following steps: determining the structural parameters of the aero-engine and the range of high and low pressure rotating speed; obtaining the sinusoidal vibration load spectrum of the engine in different typical installation positions according to the vibration environment measurement data of the typical installation position of the engine and the proportion of each typical working state in the mission profile, and calculating the sinusoidal vibration load spectrum according to the relevant standard statistical method, wherein the sinusoidal vibration load spectrum comprises a sinusoidal vibration value; determining the sinusoidal vibration fatigue number of the aero-engine accessory; determining the sweep frequency range of the accessory, and performing resonance check on the accessory in three axial directions by sinusoidal scanning vibration with predetermined sweep frequency parameters in the sweep frequency range, so as to determine the resonance frequency of the accessory product; determining the engine full-state working frequency characteristic and dividing the working frequency to obtain different frequency bands of the engine, determining the vibration fatigue number of the engine in different frequency bands, and calculating the total equivalent test time of the fixed frequency acceleration according to the resonance frequency point according to the vibration fatigue damage equivalent principle; determining the vibration scanning cycle number mainly according to the total fatigue number of the vibration durability test minus the vibration fatigue number of the resonance point, so as to obtain the remaining vibration scanning cycle number, and obtaining the acceleration vibration scanning cycle test time according to the conversion relationship between the vibration scanning cycle number and the vibration scanning cycle time; determining the vibration durability test time according to the total equivalent test time of the fixed frequency acceleration and the acceleration vibration scanning cycle test time.

2. The method of claim 1, wherein the method further comprises: determining a number of cycles to failure for the engine component; and determining a number of cycles to failure for the engine based on the number of cycles to failure for the engine component. The typical installation position of the engine comprises an engine fan case, a core engine case, a turbine rear case and an accessory case.

3. The method of claim 2, wherein the method further comprises: determining a number of cycles to failure for the engine component; and determining a number of cycles to failure for the engine based on the number of cycles to failure for the engine component. The sine vibration fatigue frequency of the aero-engine accessory is not less than 10 9 times.

4. The method of claim 3, wherein the method further comprises: determining a number of cycles to failure for the engine component; and determining a number of cycles to failure for the engine based on the number of cycles to failure for the engine component. The sweep frequency range of the accessory is 10Hz-2500Hz.

5. The method for calculating the sinusoidal vibration durability test time of aero-engine components as described in claim 4, characterized in that, The predetermined sweep frequency parameters are as follows: in the sweep frequency range of 15Hz-40Hz, the sweep frequency is performed at a sweep rate of 0.254mm and not more than 1.0 octave / minute; in the sweep frequency range above 40Hz, the sweep frequency is performed at a sweep rate of 2g acceleration and not more than 1.0 octave / minute.

6. The method of claim 1, wherein, The process of determining the total equivalent test time of the fixed frequency acceleration of the resonance frequency point is as follows: determining the engine full-state working frequency characteristic and dividing the working frequency: testing the full-state vibration environment of the typical installation position of the aero-engine to obtain the vibration environment characteristics of the engine typical installation position, including the low-pressure rotor fundamental frequency and harmonic component, the high-pressure rotor fundamental frequency and harmonic component, and the low-pressure rotor fan aerodynamic excitation component, and the division of the full-state working frequency is as follows: 1) low-pressure rotor rotating speed fundamental frequency and 2 times frequency, reflecting the low-pressure rotor unbalance and harmonic component; 2) high-pressure rotor rotating speed fundamental frequency and 2 times frequency, reflecting the high-pressure rotor unbalance and harmonic component; 3) low-pressure rotor fan blade frequency, reflecting the vibration value of fan aerodynamic excitation; 4) other frequency ranges, reflecting the vibration value of engine aerodynamic / combustion / mechanical noise; the vibration fatigue number of the engine in different frequency bands is as follows: 1) low pressure rotor speed base frequency and 2 times frequency, resonance point frequency in the frequency range of at least 10 6 fixed frequency tests; 2) High pressure rotor fundamental and 2nd harmonic, at least 10 7 fixed frequency tests at resonance point frequencies within this band. 3) Low pressure rotor fan blade frequency multiplication, at least 3 x 10 7 fixed frequency tests at resonance point frequencies within this frequency range; 4) Other frequency ranges, at least 3 x 10 7 fixed frequency tests at the resonant point frequency within this band range; calculating the total equivalent test time of the fixed frequency acceleration: T 固定频率等效时间 To fix the frequency of the equivalent time of accelerated test; f 共振频率 to the resonant frequency of the accessory product; g f Vibration magnitude for the resonance frequency point of the regular vibration load spectrum; g max is the maximum vibration value of the frequency band where the resonance frequency point is located; N 频率次数 the number of vibration fatigue for the resonance frequency point; b is the material coefficient; the total equivalent time of the fixed frequency is: m is the number of resonance points of the unidirectional accessory product.

7. The method for calculating the sinusoidal vibration durability test time of aero-engine components as described in claim 6, characterized in that, the response output vibration value of the accessory product during the fixed frequency test process is not more than the vibration limit value, and the vibration limit value G satisfies: wherein H is the vertical height from the accessory installation platform to the collection sensor; and L is the vertical height from the vibration table to the collection sensor.

8. The method for calculating the sinusoidal vibration durability test time of aero-engine components as described in claim 7, characterized in that, The process for obtaining the accelerated vibration scanning cycle test time comprises: The sinusoidal sweep cycle test between the upper and lower frequencies is performed within the sweep range, and the fatigue number N of a single sinusoidal vibration sweep is obtained for each sweep cycle time predetermined hours 扫描 : wherein: is the upper limit frequency, is the lower limit frequency; t is the single scan cycle time; determining the scanning cycle number n of the sinusoidal vibration: Wherein: is the total number of one-way vibration fatigue; is the number of fatigue for a single scanning cycle; n is the number of scanning cycles; is the vibration fatigue number of the low-pressure rotor speed base frequency and 2 times frequency; is the vibration fatigue number of the high-pressure rotor base frequency and 2 times frequency; is the vibration fatigue number of the low-pressure rotor fan blade multiple frequency; is the vibration fatigue number of other frequency ranges reflecting the engine vibration characteristics; A is the number of frequency points for fixed frequency testing in the low-pressure rotor speed base frequency and 2 times frequency range; B is the number of frequency points for fixed frequency testing in the high-pressure rotor speed base frequency and 2 times frequency range; C is the number of frequency points for fixed frequency testing in the low-pressure rotor fan blade multiple frequency range; D is the number of frequency points for fixed frequency testing in other frequency ranges; Calculate scan cycle time: ; calculating the equivalent time of the accelerated scanning cycle according to the vibration damage equivalent principle: wherein, α is a load amplification coefficient.

9. The method for calculating the sinusoidal vibration durability test time of aero-engine components as described in claim 8, characterized in that, The vibration endurance test time satisfies: 。

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