Actual measurement spectrum conversion method and system of vibration acceleration power spectrum

Abstract

The invention belongs to the technical field of structural vibration testing, and particularly relates to an actual measurement spectrum conversion method and system for a vibration acceleration power spectrum, which considers system response caused by the vibration acceleration power spectrum as excitation for conversion of the vibration acceleration power spectrum, is beneficial to make up for the defects of the existing conversion method, and improves the reliability of the vibration acceleration power spectrum. According to the method, the vibration acceleration power spectrum of the typical part in the flight process of the turboprop aircraft can be reasonably and effectively converted into the actual measurement spectrum, so that the vibration environment test is carried out on the airborne equipment, a result conforming to the reality can be obtained, and the design and improvement of the airborne equipment can be effectively guided.

Description

Technical Field

[0001] The present application belongs to the technical field of structural vibration testing, and specifically relates to a method and system for converting a measured spectrum of a vibration acceleration power spectrum. Background Art

[0002] The vibration acceleration power spectrum of typical parts of a turboprop aircraft during flight is shown in Figure 2. Figure 1 As shown, it is usually composed of a broadband spectrum and several narrowband spectra, wherein the peak frequency of the narrowband spectrum corresponds to the propeller's passing frequency and its multiples.

[0003] In order to facilitate the vibration environment test of turboprop aircraft airborne equipment, it is necessary to convert the vibration acceleration power spectrum into the measured spectrum, that is, a more regular vibration acceleration power spectrum, as one of the input conditions of the vibration environment test.

[0004] Currently, the following two methods are usually used to convert the vibration acceleration power spectrum into the measured spectrum:

[0005] 1) Based on statistical theory or extreme value theory, the envelope spectrum of the vibration acceleration power spectrum is taken, that is, the amplitude of the broadband spectrum is taken as its statistical value or maximum value, and the amplitude of the narrowband spectrum is taken as its peak value. The bandwidth of the narrowband spectrum is taken as 95% to 105% of the corresponding peak frequency to obtain the measured spectrum, such as Figure 2 As shown;

[0006] 2) Based on the principle of area equivalence, the area occupied by the broadband spectrum is calculated, and the area is divided by the bandwidth of the broadband spectrum. The quotient obtained is used as the amplitude of the broadband spectrum. The area of ​​each narrowband spectrum is calculated separately, and the area is divided by the bandwidth of the narrowband spectrum. The bandwidth is 95% to 105% of the corresponding peak frequency. The quotient obtained is used as the amplitude of the narrowband spectrum to obtain the measured spectrum, such as Figure 3 shown.

[0007] The above two methods of converting the vibration acceleration power spectrum into the measured spectrum only process the vibration acceleration power spectrum itself, and do not consider the random vibration response caused by the vibration acceleration power spectrum as an excitation, that is, the response of the airborne equipment to the vibration environment spectrum. It is difficult to obtain results consistent with the actual situation by conducting vibration environment tests on airborne equipment in this way, and it cannot effectively guide the design and improvement of airborne equipment.

[0008] This application is proposed in view of the above-mentioned technical defects. Summary of the invention

[0009] The purpose of the present application is to provide a method and system for converting a measured spectrum of a vibration acceleration power spectrum to overcome or alleviate at least one of the known technical deficiencies.

[0010] The technical solution of this application is:

[0011] On the one hand, a method for converting a measured spectrum of a vibration acceleration power spectrum is provided, comprising:

[0012] Calculation steps of random vibration response spectrum of vibration acceleration power spectrum: Calculate the random vibration response spectrum of vibration acceleration power spectrum;

[0013] Measured spectrum construction steps: construct the measured spectrum;

[0014] The steps of setting the amplitude of the measured spectrum wideband spectrum and its narrowband spectrum are as follows: setting the amplitude of the measured spectrum wideband spectrum and its narrowband spectrum;

[0015] Calculation steps of random vibration response spectrum of measured spectrum: Calculate the random vibration response spectrum of measured spectrum;

[0016] Calculation and determination steps of the random vibration response error between the measured spectrum and the vibration acceleration power spectrum: Calculate and determine the random vibration response error between the measured spectrum and the vibration acceleration power spectrum. If the error is greater than the set error threshold, reset the amplitude of the corresponding frequency spectrum in the measured spectrum, and repeat the calculation steps of the random vibration response spectrum of the measured spectrum and the calculation and determination steps of the random vibration response error between the measured spectrum and the vibration acceleration power spectrum until the error is less than the set error threshold.

[0017] According to at least one embodiment of the present application, in the above-mentioned measured spectrum conversion method of the vibration acceleration power spectrum, in the step of calculating the random vibration response spectrum of the vibration acceleration power spectrum, the vibration acceleration power spectrum is used as the basic acceleration power spectrum density Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the vibration acceleration power spectrum n -δ rms ;

[0018] In the random vibration response spectrum calculation step, the measured spectrum is used as the basic acceleration power spectrum density Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the measured spectrum n -δ rms ;

[0019] The specific calculation formula is:

[0020]

[0021]

[0022] in,

[0023] G A (f) is the power spectrum density of relative displacement;

[0024] f is the excitation frequency;

[0025] ζ is the critical damping ratio.

[0026] According to at least one embodiment of the present application, in the above-mentioned method for converting the measured spectrum of the vibration acceleration power spectrum, in the step of calculating the random vibration response spectrum of the vibration acceleration power spectrum, and in the step of calculating the random vibration response spectrum of the measured spectrum, the critical damping ratio ζ is taken as 0.05.

[0027] According to at least one embodiment of the present application, in the above-mentioned method for converting the measured spectrum of the vibration acceleration power spectrum, in the step of calculating the random vibration response spectrum of the vibration acceleration power spectrum, and in the step of calculating the random vibration response spectrum of the measured spectrum, the step size of the excitation frequency f is 0.01 Hz.

[0028] According to at least one embodiment of the present application, in the above-mentioned method for converting the measured spectrum of the vibration acceleration power spectrum, in the step of calculating the random vibration response spectrum of the vibration acceleration power spectrum, and in the step of calculating the random vibration response spectrum of the measured spectrum, the natural frequency f n The step size is 0.1Hz.

[0029] According to at least one embodiment of the present application, in the above-mentioned measured spectrum conversion method of the vibration acceleration power spectrum, in the measured spectrum construction step, the characteristic frequencies of the measured spectrum include f a 、f b ,f1,f2,f3,…,f j ,in,

[0030] f a is the starting frequency, usually 15Hz;

[0031] f b is the termination frequency, and the cutoff frequency of the vibration acceleration power spectrum is taken;

[0032] f1, f2, f3, …, f j is the peak frequency of each narrowband spectrum, corresponding to the peak frequency of each narrowband spectrum in the vibration acceleration power spectrum.

[0033] According to at least one embodiment of the present application, in the measured spectrum conversion method of the above-mentioned vibration acceleration power spectrum, in the measured spectrum construction step, the bandwidth of each narrowband spectrum of the measured spectrum is constructed, and takes 95% to 105% of the corresponding peak frequency in the vibration acceleration power spectrum.

[0034] According to at least one embodiment of the present application, in the above-mentioned measured spectrum conversion method of the vibration acceleration power spectrum, in the step of setting the amplitude of the measured spectrum broadband spectrum and its narrowband spectrum, the amplitude G0 of the measured spectrum broadband spectrum is set, and the amplitudes G1, G2, G3, ..., G1 of the measured spectrum narrowband spectrum are set. j .

[0035] According to at least one embodiment of the present application, in the above-mentioned measured spectrum conversion method of the vibration acceleration power spectrum, in the step of calculating and determining the random vibration response error between the measured spectrum and the vibration acceleration power spectrum, the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum in the measured spectrum and the vibration acceleration power spectrum, and the relative errors err1, err2, err3, ..., err4, err5, err6, err7, err8, err9, err10, err11, err12, err13, err14, err15, err16, err17, err18, err19, err20, err21, err22, err3, err3, err4, err5, err6, err7, err8, err9, err10, err11, err12, err23, err3, err j ;

[0036] If the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err j If there is a value greater than the set error threshold, the amplitude of the corresponding spectrum in the measured spectrum is reset, and the steps of calculating the random vibration response spectrum of the measured spectrum and calculating and judging the random vibration response error between the measured spectrum and the vibration acceleration power spectrum are repeated until the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, …, err4, caused by each narrowband spectrum are j There is no value greater than the set error threshold, thus the measured spectrum is obtained.

[0037] According to at least one embodiment of the present application, in the above-mentioned method for converting the measured spectrum of the vibration acceleration power spectrum, in the step of calculating and determining the error between the measured spectrum and the random vibration response of the vibration acceleration power spectrum, the error threshold is set to 2%.

[0038] On the other hand, a system for converting a measured spectrum of a vibration acceleration power spectrum is provided, comprising:

[0039] A vibration acceleration power spectrum random vibration response spectrum calculation module is used to calculate the random vibration response spectrum of the vibration acceleration power spectrum;

[0040] A measured spectrum construction module, used to construct a measured spectrum;

[0041] A module for setting the amplitude of the measured spectrum broadband spectrum and its narrowband spectrum, used to set the amplitude of the measured spectrum broadband spectrum and its narrowband spectrum;

[0042] A random vibration response spectrum calculation module of a measured spectrum is used to calculate the random vibration response spectrum of the measured spectrum;

[0043] The module for calculating and determining the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum is used to calculate and determine the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum. If the error is greater than the set error threshold, the amplitude of the corresponding frequency spectrum in the measured spectrum is reset, and the module for calculating the random vibration response spectrum of the measured spectrum calculates and determines the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum until the error is less than the set error threshold.

[0044] According to at least one embodiment of the present application, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the vibration acceleration power spectrum random vibration response spectrum calculation module, the vibration acceleration power spectrum is used as the basic acceleration power spectrum density Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the vibration acceleration power spectrum n -δ rms ;

[0045] In the random vibration response spectrum calculation module, the measured spectrum is used as the basic acceleration power spectrum density Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the measured spectrum n -δ rms ;

[0046] The specific calculation formula is:

[0047]

[0048]

[0049] in,

[0050] G A (f) is the power spectrum density of relative displacement;

[0051] f is the excitation frequency;

[0052] ζ is the critical damping ratio.

[0053] According to at least one embodiment of the present application, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the vibration acceleration power spectrum random vibration response spectrum calculation module, and in the measured spectrum random vibration response spectrum calculation module, the critical damping ratio ζ is taken as 0.05.

[0054] According to at least one embodiment of the present application, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the vibration acceleration power spectrum random vibration response spectrum calculation module, and in the measured spectrum random vibration response spectrum calculation module, the step size of the excitation frequency f is 0.01 Hz.

[0055] According to at least one embodiment of the present application, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the vibration acceleration power spectrum random vibration response spectrum calculation module, and in the measured spectrum random vibration response spectrum calculation module, the natural frequency f n The step size is 0.1Hz.

[0056] According to at least one embodiment of the present application, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the measured spectrum construction module, the characteristic frequencies of constructing the measured spectrum include f a 、f b ,f1,f2,f3,…,f j ,in,

[0057] f a is the starting frequency, usually 15Hz;

[0058] f b is the termination frequency, and the cutoff frequency of the vibration acceleration power spectrum is taken;

[0059] f1, f2, f3, …, f j is the peak frequency of each narrowband spectrum, corresponding to the peak frequency of each narrowband spectrum in the vibration acceleration power spectrum.

[0060] According to at least one embodiment of the present application, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the measured spectrum construction module, the bandwidth of each narrowband spectrum of the measured spectrum is constructed, and is 95% to 105% of the corresponding peak frequency in the vibration acceleration power spectrum.

[0061] According to at least one embodiment of the present application, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the measured spectrum broadband spectrum and its narrowband spectrum amplitude setting module, the amplitude G0 of the measured spectrum broadband spectrum is set, and the amplitudes G1, G2, G3, ..., G1 of the measured spectrum narrowband spectrum are set. j .

[0062] According to at least one embodiment of the present application, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the random vibration response error calculation and determination module of the measured spectrum and the vibration acceleration power spectrum, the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum in the measured spectrum and the vibration acceleration power spectrum, and the relative errors err1, err2, err3, ..., err4, err5, err6, err7, err8, err9, err10, err11, err12, err13, err14, err15, err16, err17, err18, err19, err20, err21, err22, err3, err3, err4, err5, err6, err7, err8, err9, err10, err11, err12, err23, err3, errj ;

[0063] If the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err j If there is a value greater than the set error threshold, the amplitude of the corresponding spectrum in the measured spectrum is reset, and the measured spectrum random vibration response spectrum calculation module and the measured spectrum and vibration acceleration power spectrum random vibration response error calculation and judgment module are re-performed until the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err4, caused by each narrowband spectrum are j There is no value greater than the set error threshold, thus the measured spectrum is obtained.

[0064] According to at least one embodiment of the present application, in the above-mentioned measured spectrum conversion system of the vibration acceleration power spectrum, in the random vibration response error calculation and determination module between the measured spectrum and the vibration acceleration power spectrum, an error threshold is set to 2%.

[0065] This application has at least the following beneficial technical effects:

[0066] Provided are a measured spectrum conversion method and system for a vibration acceleration power spectrum. The conversion of the vibration acceleration power spectrum takes into account the system response caused by the vibration acceleration power spectrum as an excitation, which helps to make up for the shortcomings of the existing conversion method. The vibration acceleration power spectrum of a typical part of a turboprop aircraft during flight can be reasonably and effectively converted into a measured spectrum. Vibration environment tests of airborne equipment can be performed on the method, and results consistent with reality can be obtained, which can effectively guide the design and improvement of airborne equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 1 is a schematic diagram of a vibration acceleration power spectrum measured at a typical part of a turboprop aircraft during flight provided by an embodiment of the present application;

[0068] Figure 2 It is a schematic diagram of converting the vibration acceleration power spectrum into a measured spectrum based on statistical theory or extreme value theory provided in an embodiment of the present application;

[0069] Figure 3 It is a schematic diagram of converting the vibration acceleration power spectrum into a measured spectrum based on the principle of area equivalence provided in an embodiment of the present application;

[0070] Figure 4 It is a schematic diagram of a measured spectrum conversion method of a vibration acceleration power spectrum provided in an embodiment of the present application;

[0071] Figure 5It is a schematic diagram of the measured spectrum form provided in the embodiment of the present application;

[0072] Figure 6 It is a schematic diagram of a random vibration response spectrum of a vibration acceleration power spectrum of a typical part of a turboprop aircraft during flight provided by an embodiment of the present application;

[0073] Figure 7 This is a schematic diagram of the preliminary construction of the measured spectrum provided in the embodiment of the present application;

[0074] Figure 8 is a schematic diagram of a random vibration response spectrum of a preliminary constructed measured spectrum provided in an embodiment of the present application;

[0075] Fig. 9 is a schematic diagram of the measured spectrum after optimization provided in the embodiment of the present application;

[0076] Fig.10 It is a comparison diagram of the random vibration response of the optimized measured spectrum and the original vibration acceleration power spectrum provided in the embodiment of the present application.

[0077] Fig.11 It is a schematic diagram of a measured spectrum conversion system of a vibration acceleration power spectrum provided in an embodiment of the present application.

[0078] In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be construed as limitations on the present application. DETAILED DESCRIPTION

[0079] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0080] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0081] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0082] For a single degree of freedom linear system, the oscillator has a base acceleration The vibration response equation under excitation is as follows:

[0083]

[0084] in,

[0085] m is the mass of the oscillator; c is the damping; k is the stiffness;

[0086] is the acceleration time history of the oscillator response; is the time history of the oscillator response speed; x(t) is the time history of the oscillator response displacement;

[0087] is the basic speed time history; x s (t) is the basic displacement time history.

[0088] Introduce the relative displacement δ(t) of the oscillator:

[0089] δ(t)=x(t)-x s (t)……………… (2)

[0090] Accordingly, the relative speed and relative acceleration They are:

[0091]

[0092]

[0093] Introduce the natural circular frequency ω of the single degree of freedom system n And the critical damping ratio ζ:

[0094]

[0095]

[0096] Where:

[0097] f n is the natural frequency of the single degree of freedom system.

[0098] Substituting equations (2) to (6) into equation (1), we get:

[0099]

[0100] Assume that the relative displacement time history δ(t) and the basic acceleration time history for:

[0101]

[0102] in,

[0103] A is the amplitude of relative displacement; i is the imaginary unit; ω is the excitation circular frequency; t is the time; is the amplitude of the basic acceleration;

[0104] Substituting equation (8) into equation (7) and converting it to the frequency domain, we get:

[0105]

[0106] It can be seen that the frequency response function between relative displacement and basic acceleration is:

[0107]

[0108] in,

[0109] f is the excitation frequency.

[0110] Assume the power spectrum density of the basic acceleration is The power spectral density of the relative displacement is G A (f), then the two satisfy the relationship:

[0111]

[0112] The root mean square value of the relative displacement is:

[0113]

[0114] If the basic acceleration power spectral density is known According to equations (11) and (12), different natural frequencies f can be calculated: n Next The root mean square value of the relative displacement caused by rms , f n -δ rms As a random vibration response spectrum.

[0115] Based on the above, the present application provides a method for converting the measured spectrum of the vibration acceleration power spectrum, such as Figure 4 shown.

[0116] Calculation steps of random vibration response spectrum of vibration acceleration power spectrum: Calculate the random vibration response spectrum of vibration acceleration power spectrum.

[0117] The vibration acceleration power spectrum is used as the basic acceleration power spectrum density According to formula (11) and formula (12), different natural frequencies f are calculated. n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the vibration acceleration power spectrum n -δ rms .

[0118] Measured spectrum construction steps: Construct the measured spectrum.

[0119] The horizontal axis of the measured spectrum is frequency in Hz, and the vertical axis is the acceleration power spectrum density amplitude in g. 2 / Hz.

[0120] The characteristic frequencies of the measured spectrum include f a 、f b ,f1,f2,f3,…,f j , where f a is the starting frequency, usually 15Hz; f b is the termination frequency, and the cutoff frequency of the vibration acceleration power spectrum is taken; f1, f2, f3, ..., f j is the peak frequency of each narrowband spectrum, corresponding to the peak frequency of each narrowband spectrum in the vibration acceleration power spectrum.

[0121] The bandwidth of each narrowband spectrum in the measured spectrum is 95% to 105% of the corresponding peak frequency in the vibration acceleration power spectrum.

[0122] Steps for setting the amplitudes of the measured wideband spectrum and its narrowband spectrum: set the amplitudes of the measured wideband spectrum and its narrowband spectrum.

[0123] Set the amplitude G0 of the measured spectrum wideband spectrum wideband spectrum, and set the amplitude G1, G2, G3, ..., G of the measured spectrum narrowband spectrum wideband spectrum j , corresponding to the characteristic frequencies f1, f2, f3, ..., f j The corresponding narrowband spectrum is Figure 5 shown.

[0124] Calculation steps of random vibration response spectrum of measured spectrum: Calculate the random vibration response spectrum of the measured spectrum.

[0125] The measured spectrum is used as the basic acceleration power spectral density According to formula (11) and formula (12), different natural frequencies f are calculated. n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the measured spectrum n -δ rms .

[0126] Steps for calculating and determining the random vibration response error between the measured spectrum and the vibration acceleration power spectrum: Calculate and determine the random vibration response error between the measured spectrum and the vibration acceleration power spectrum.

[0127] Calculate the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum in the measured spectrum and the vibration acceleration power spectrum, as well as the relative errors err1, err2, err3, ..., err4, err5, err6, err7, err8, err9, err10, err11, err2, err3, ..., err12, err13, err14, err15, err16, err17, err18, err19, err20, err21, err22, err3, err3 j .

[0128] If the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err j If there is a value greater than the set error threshold, the amplitude of the corresponding spectrum in the measured spectrum is reset, and the steps of calculating the random vibration response spectrum of the measured spectrum and calculating and judging the random vibration response error between the measured spectrum and the vibration acceleration power spectrum are repeated until the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, …, err4, caused by each narrowband spectrum are j There is no value greater than the set error threshold, thus the measured spectrum is obtained.

[0129] The error threshold may be set to 2%.

[0130] The measured spectrum conversion method of the vibration acceleration power spectrum disclosed in the above embodiment is used to Figure 1 The power spectrum of vibration acceleration of typical parts of a turboprop aircraft during flight is shown and converted as follows.

[0131] S1. The vibration acceleration power spectrum of typical parts of turboprop aircraft during flight is used as the basic acceleration power spectrum density According to equations (11) and (12), different natural frequencies f are calculated. n Next The root mean square of the relative displacement caused by rms , the random vibration response spectrum f of the vibration acceleration power spectrum of typical parts of the turboprop aircraft during flight is obtained n -δ rms ,like Figure 6 shown.

[0132] S2. Construct the measured spectrum:

[0133] The horizontal axis of the measured spectrum is frequency in Hz, and the vertical axis is the acceleration power spectrum density amplitude in g2 / Hz.

[0134] In the vibration acceleration power spectrum of typical parts of a turboprop aircraft during flight, the cutoff frequency is 600 Hz, there are five narrow-band spectra, and the corresponding peak frequencies are 108 Hz, 216 Hz, 324 Hz, 432 Hz, and 540 Hz.

[0135] The measured spectrum is the starting frequency f a Take 15Hz, the end frequency f b Take 600Hz, the characteristic frequencies f1, f2, f3, f4, and f5 are 108Hz, 216Hz, 324Hz, 432Hz, and 540Hz respectively, and the bandwidth of the narrowband spectrum is 95% to 105% of the corresponding peak frequency. The upper and lower limit frequencies of the corresponding narrowband spectrum are 102.6Hz to 113.4Hz, 205.2Hz to 226.8Hz, 307.8Hz to 340.2Hz, 410.4Hz to 453.6Hz, and 513.0Hz to 567.0Hz respectively.

[0136] S3, preliminarily set the amplitude G0 of the measured spectrum broadband spectrum to 0.0003g2 / Hz, and set the amplitudes G1, G2, G3, G4, and G5 of the measured spectrum narrowband spectrum broadband spectrum to 0.02g2 / Hz, 0.01g2 / Hz, 0.005g2 / Hz, 0.0025g2 / Hz, and 0.00125g2 / Hz respectively, then preliminarily construct the measured spectrum as follows Figure 7 The specific values ​​are shown in the following table:

[0137] S4. According to GJB150.18A-2009, the quality factor for random vibration response spectrum analysis is generally 10, which is equivalent to 5% critical viscous damping. Therefore, the critical damping ratio ζ = 0.05 is set, the excitation frequency f is set to a range of 15Hz to 600Hz, the frequency step is 0.1Hz, and the natural frequency f is set to n The frequency range is 15Hz~600Hz, and the frequency step is 1Hz.

[0138] The measured spectrum is used as the basic acceleration power spectral density According to formula (11) and formula (12), different natural frequencies f are calculated. n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the measured spectrum n -δ rms ,like Figure 8 shown.

[0139] S5. Calculate the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, err4, and err5 of the maximum vibration response amplitude caused by each narrowband spectrum in the measured spectrum and the vibration acceleration power spectrum. The specific values ​​are shown in the following table: Relative error sign Relative error value <![CDATA[err0]]> 24.42％ <![CDATA[err1]]> 8.98％ <![CDATA[err2]]> 2.43％ <![CDATA[err3]]> 3.84％ <![CDATA[err4]]> 3.14％ <![CDATA[err5]]> 11.10％

[0140] If the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum, and the relative errors err1, err2, err3, err4, and err5 of the maximum vibration response amplitude caused by each narrowband spectrum are all greater than the set error threshold of 2%, then the amplitude G0 of the broadband spectrum of the measured spectrum in the measured spectrum is reset, and the amplitudes G1, G2, G3, G4, and G5 of the broadband spectrum of the narrowband spectrum of the measured spectrum are reset to optimize the measured spectrum, such as Fig. 9 The specific values ​​are shown in the following table: Frequency / Hz <![CDATA[Measured spectrum amplitude / (g 2 / Hz)]]> 15.0 0.0002 102.5 0.0002 102.6 0.0243 113.4 0.0243 113.5 0.0002 205.1 0.0002 205.2 0.0094 226.8 0.0094 226.9 0.0002 307.7 0.0002 307.8 0.00446 340.2 0.00446 340.3 0.0002 410.3 0.0002 410.4 0.0028 453.6 0.0028 453.7 0.0002 512.9 0.0002 513.0 0.00176 567.0 0.00176 567.1 0.0002 600.0 0.0002

[0141] Repeat S4 to S5 to obtain the random vibration response spectrum f of the measured spectrum. n -δ rms , and calculate the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum in the measured spectrum and the vibration acceleration power spectrum, as well as the relative errors err1, err2, err3, err4, err5 of the maximum vibration response amplitude caused by each narrowband spectrum. The specific values ​​are shown in the following table:

[0142] It can be seen that the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum, and the relative errors err1, err2, err3, err4, and err5 of the maximum vibration response amplitude caused by each narrowband spectrum are all less than the set error threshold of 2%. The optimized measured spectrum meets the design requirements, and the measured spectrum is obtained.

[0143] Comparison of the random vibration response spectrum corresponding to the measured spectrum after optimization and the random vibration response spectrum corresponding to the vibration acceleration power spectrum (PSD), such as Fig.10 As shown, the two are in good agreement.

[0144] The measured spectrum conversion method of the vibration acceleration power spectrum disclosed in the above embodiment aims to consider the system response caused by the vibration acceleration power spectrum as the excitation, take the vibration acceleration power spectrum as the basic excitation, calculate the random vibration response spectrum caused by it, take the response spectrum as the optimization target, and adjust the amplitudes of the broadband spectrum and the narrowband spectrum in the initial measured spectrum so that the random vibration response spectrum caused by it is consistent with the optimization target, thereby obtaining the measured spectrum.

[0145] The method for converting the measured spectrum of the vibration acceleration power spectrum disclosed in the above embodiment takes into account the system response caused by the vibration acceleration power spectrum as an excitation, which helps to make up for the shortcomings of the existing conversion methods. The vibration acceleration power spectrum of typical parts of the turboprop aircraft during flight can be reasonably and effectively converted into a measured spectrum, so that the vibration environment test of the airborne equipment can be carried out, and the results consistent with the actual can be obtained, which can effectively guide the design and improvement of the airborne equipment.

[0146] Based on the above, the present application provides a vibration acceleration power spectrum conversion system, such as Fig.11 shown.

[0147] The vibration acceleration power spectrum random vibration response spectrum calculation module is used to calculate the random vibration response spectrum of the vibration acceleration power spectrum.

[0148] The vibration acceleration power spectrum is used as the basic acceleration power spectrum density According to formula (11) and formula (12), different natural frequencies f are calculated. n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the vibration acceleration power spectrum n -δ rms .

[0149] The measured spectrum construction module is used to construct the measured spectrum.

[0150] The horizontal axis of the measured spectrum is frequency in Hz, and the vertical axis is the acceleration power spectrum density amplitude in g2 / Hz.

[0151] The characteristic frequencies of the measured spectrum include f a 、f b ,f1,f2,f3,…,f j , where f a is the starting frequency, usually 15Hz; f b is the termination frequency, and the cutoff frequency of the vibration acceleration power spectrum is taken; f1, f2, f3, ..., f j is the peak frequency of each narrowband spectrum, corresponding to the peak frequency of each narrowband spectrum in the vibration acceleration power spectrum.

[0152] The bandwidth of each narrowband spectrum in the measured spectrum is 95% to 105% of the corresponding peak frequency in the vibration acceleration power spectrum.

[0153] The module for setting the amplitude of the measured spectrum wideband spectrum and its narrowband spectrum is used to set the amplitude of the measured spectrum wideband spectrum and its narrowband spectrum.

[0154] Set the amplitude G0 of the measured spectrum wideband spectrum wideband spectrum, and set the amplitude G1, G2, G3, ..., G of the measured spectrum narrowband spectrum wideband spectrum j , corresponding to the characteristic frequencies f1, f2, f3, ..., f j The corresponding narrowband spectrum.

[0155] The measured spectrum random vibration response spectrum calculation module is used to calculate the random vibration response spectrum of the measured spectrum.

[0156] The measured spectrum is used as the basic acceleration power spectral density According to formula (11) and formula (12), different natural frequencies f are calculated. n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the measured spectrum n -δ rms .

[0157] The module for calculating and determining the random vibration response error between the measured spectrum and the vibration acceleration power spectrum is used to calculate and determine the random vibration response error between the measured spectrum and the vibration acceleration power spectrum.

[0158] Calculate the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum in the measured spectrum and the vibration acceleration power spectrum, as well as the relative errors err1, err2, err3, ..., err4, err5, err6, err7, err8, err9, err10, err11, err2, err3, ..., err12, err13, err14, err15, err16, err17, err18, err19, err20, err21, err22, err3, err3 j .

[0159] If the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err j If there is a value greater than the set error threshold, the amplitude of the corresponding spectrum in the measured spectrum is reset, and the random vibration response spectrum of the measured spectrum is calculated until the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err1 of the maximum vibration response amplitude caused by each narrowband spectrum are j There is no value greater than the set error threshold, thus the measured spectrum is obtained.

[0160] The error threshold may be set to 2%.

[0161] On the other hand, a system for converting a measured spectrum of a vibration acceleration power spectrum is provided, comprising:

[0162] A vibration acceleration power spectrum random vibration response spectrum calculation module is used to calculate the random vibration response spectrum of the vibration acceleration power spectrum;

[0163] A measured spectrum construction module, used to construct a measured spectrum;

[0164] A module for setting the amplitude of the measured spectrum broadband spectrum and its narrowband spectrum, used to set the amplitude of the measured spectrum broadband spectrum and its narrowband spectrum;

[0165] A random vibration response spectrum calculation module of a measured spectrum is used to calculate the random vibration response spectrum of the measured spectrum;

[0166] The module for calculating and determining the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum is used to calculate and determine the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum. If the error is greater than the set error threshold, the amplitude of the corresponding frequency spectrum in the measured spectrum is reset, and the module for calculating the random vibration response spectrum of the measured spectrum calculates and determines the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum until the error is less than the set error threshold.

[0167] Optionally, in the above-mentioned measured spectrum conversion system of the vibration acceleration power spectrum, in the vibration acceleration power spectrum random vibration response spectrum calculation module, the vibration acceleration power spectrum is used as the basic acceleration power spectrum density Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the vibration acceleration power spectrum n -δ rms ;

[0168] In the random vibration response spectrum calculation module, the measured spectrum is used as the basic acceleration power spectrum density Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the measured spectrum n -δ rms ;

[0169] The specific calculation formula is:

[0170]

[0171]

[0172] in,

[0173] G A (f) is the power spectrum density of relative displacement;

[0174] f is the excitation frequency;

[0175] ζ is the critical damping ratio.

[0176] Optionally, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the vibration acceleration power spectrum random vibration response spectrum calculation module, and in the measured spectrum random vibration response spectrum calculation module, the critical damping ratio ζ is taken as 0.05.

[0177] Optionally, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the vibration acceleration power spectrum random vibration response spectrum calculation module, and in the measured spectrum random vibration response spectrum calculation module, the step size of the excitation frequency f is 0.01 Hz.

[0178] Optionally, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the vibration acceleration power spectrum random vibration response spectrum calculation module, and in the measured spectrum random vibration response spectrum calculation module, the natural frequency f n The step size is 0.1Hz.

[0179] Optionally, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the measured spectrum construction module, the characteristic frequencies of the measured spectrum include f a 、f b ,f1,f2,f3,…,f j ,in,

[0180] f a is the starting frequency, usually 15Hz;

[0181] f b is the termination frequency, and the cutoff frequency of the vibration acceleration power spectrum is taken;

[0182] f1, f2, f3, …, f j is the peak frequency of each narrowband spectrum, corresponding to the peak frequency of each narrowband spectrum in the vibration acceleration power spectrum.

[0183] Optionally, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the measured spectrum construction module, the bandwidth of each narrowband frequency spectrum of the measured spectrum is constructed to be 95% to 105% of the corresponding peak frequency in the vibration acceleration power spectrum.

[0184] Optionally, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the measured spectrum broadband spectrum and its narrowband spectrum amplitude setting module, the amplitude G0 of the measured spectrum broadband spectrum is set, and the amplitudes G1, G2, G3, ..., G1 of the measured spectrum narrowband spectrum are set. j.

[0185] Optionally, in the measured spectrum conversion system of the vibration acceleration power spectrum, in the random vibration response error calculation and judgment module of the measured spectrum and the vibration acceleration power spectrum, the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum in the measured spectrum and the vibration acceleration power spectrum, and the relative errors err1, err2, err3, ..., err4, err5, err6, err7, err8, err9, err10, err11, err2, err3, ..., err12, err3, err13, err14, err15, err16, err17, err18, err19, err20, err21, err22, err3, err3, err4, err5, err6, err7, err8, err9, err10, err11, err2 j ;

[0186] If the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err j If there is a value greater than the set error threshold, the amplitude of the corresponding spectrum in the measured spectrum is reset, and the measured spectrum random vibration response spectrum calculation module and the measured spectrum and vibration acceleration power spectrum random vibration response error calculation and judgment module are re-performed until the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err4, caused by each narrowband spectrum are j There is no value greater than the set error threshold, thus the measured spectrum is obtained.

[0187] Optionally, in the above-mentioned measured spectrum conversion system of the vibration acceleration power spectrum, in the random vibration response error calculation and determination module between the measured spectrum and the vibration acceleration power spectrum, an error threshold is set to 2%.

[0188] Regarding the measured spectrum conversion system of the vibration acceleration power spectrum disclosed in the above embodiment, since it corresponds to the measured spectrum conversion method of the vibration acceleration power spectrum disclosed in the above embodiment, the description is relatively simple. For specific related matters, please refer to the relevant instructions in the part of the measured spectrum conversion method of the vibration acceleration power spectrum. Its technical effects can also refer to the technical effects of the relevant part of the measured spectrum conversion method of the vibration acceleration power spectrum, which will not be repeated here.

[0189] In addition, technicians in the field should also be able to realize that the various modules and units of the measured spectrum conversion system of the vibration acceleration power spectrum disclosed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, this application generally describes them according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Technicians in the field can choose to adopt different methods to implement the described functions for each specific application and its actual constraints, but such implementation should not be considered to be beyond the scope of this application.

[0190] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for converting a measured spectrum of a vibration acceleration power spectrum, characterized in that: include: Calculation steps of random vibration response spectrum of vibration acceleration power spectrum: Calculate the random vibration response spectrum of vibration acceleration power spectrum; Measured spectrum construction steps: construct the measured spectrum; The steps of setting the amplitude of the measured spectrum wideband spectrum and its narrowband spectrum are as follows: setting the amplitude of the measured spectrum wideband spectrum and its narrowband spectrum; Calculation steps of random vibration response spectrum of measured spectrum: Calculate the random vibration response spectrum of measured spectrum; Calculation and determination steps of the random vibration response error between the measured spectrum and the vibration acceleration power spectrum: Calculate and determine the random vibration response error between the measured spectrum and the vibration acceleration power spectrum. If the error is greater than the set error threshold, reset the amplitude of the corresponding frequency spectrum in the measured spectrum, and repeat the calculation steps of the random vibration response spectrum of the measured spectrum and the calculation and determination steps of the random vibration response error between the measured spectrum and the vibration acceleration power spectrum until the error is less than the set error threshold.

2. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 1 is characterized in that: In the calculation step of random vibration response spectrum, the vibration acceleration power spectrum is used as the basic acceleration power spectrum density. Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the vibration acceleration power spectrum n -δ rms ; In the random vibration response spectrum calculation step, the measured spectrum is used as the basic acceleration power spectrum density Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the measured spectrum n -δ rms ; The specific calculation formula is: in, G A (f) is the power spectrum density of relative displacement; f is the excitation frequency; ζ is the critical damping ratio.

3. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 2 is characterized in that: In the calculation step of the random vibration response spectrum of the vibration acceleration power spectrum and the calculation step of the random vibration response spectrum of the measured spectrum, the critical damping ratio ζ is taken as 0.

05.

4. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 3 is characterized in that: In the calculation step of the random vibration response spectrum of the vibration acceleration power spectrum and the calculation step of the random vibration response spectrum of the measured spectrum, the step size of the excitation frequency f is 0.01 Hz.

5. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 4 is characterized in that: In the calculation step of the random vibration response spectrum of the vibration acceleration power spectrum and the random vibration response spectrum of the measured spectrum, the natural frequency f n The step size is 0.1Hz.

6. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 5 is characterized in that: In the step of constructing the measured spectrum, the characteristic frequencies of the measured spectrum include f a 、f b ,f1,f2,f3,…,f j ,in, f a is the starting frequency, usually 15Hz; f b is the termination frequency, and the cutoff frequency of the vibration acceleration power spectrum is taken; f1, f2, f3, …, f j is the peak frequency of each narrowband spectrum, corresponding to the peak frequency of each narrowband spectrum in the vibration acceleration power spectrum.

7. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 6 is characterized in that: In the step of constructing the measured spectrum, the bandwidth of each narrowband frequency spectrum of the measured spectrum is constructed to be 95% to 105% of the corresponding peak frequency in the vibration acceleration power spectrum.

8. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 7 is characterized in that: In the step of setting the amplitude of the measured spectrum broadband spectrum and its narrowband spectrum, the amplitude G0 of the measured spectrum broadband spectrum is set, and the amplitudes G1, G2, G3, ..., G1 of the measured spectrum narrowband spectrum and the wideband spectrum are set. j .

9. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 8 is characterized in that: In the step of calculating and determining the random vibration response error between the measured spectrum and the vibration acceleration power spectrum, the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum in the measured spectrum and the vibration acceleration power spectrum, and the relative errors err1, err2, err3, ..., err j ; If the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err j If there is a value greater than the set error threshold, the amplitude of the corresponding spectrum in the measured spectrum is reset, and the steps of calculating the random vibration response spectrum of the measured spectrum and calculating and judging the random vibration response error between the measured spectrum and the vibration acceleration power spectrum are repeated until the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, …, err4, caused by each narrowband spectrum are j There is no value greater than the set error threshold, thus the measured spectrum is obtained.

10. The measured spectrum conversion method of the vibration acceleration power spectrum according to claim 9 is characterized in that: In the step of calculating and determining the error between the measured spectrum and the vibration acceleration power spectrum random vibration response, the error threshold is set to 2%.

11. A measured spectrum conversion system for vibration acceleration power spectrum, characterized in that: include: A vibration acceleration power spectrum random vibration response spectrum calculation module is used to calculate the random vibration response spectrum of the vibration acceleration power spectrum; A measured spectrum construction module, used to construct a measured spectrum; A module for setting the amplitude of the measured spectrum broadband spectrum and its narrowband spectrum, used to set the amplitude of the measured spectrum broadband spectrum and its narrowband spectrum; A random vibration response spectrum calculation module of a measured spectrum is used to calculate the random vibration response spectrum of the measured spectrum; The module for calculating and determining the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum is used to calculate and determine the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum. If the error is greater than the set error threshold, the amplitude of the corresponding frequency spectrum in the measured spectrum is reset, and the module for calculating the random vibration response spectrum of the measured spectrum calculates and determines the error between the random vibration response of the measured spectrum and the vibration acceleration power spectrum until the error is less than the set error threshold.

12. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 11, characterized in that: In the random vibration response spectrum calculation module, the vibration acceleration power spectrum is used as the basic acceleration power spectrum density. Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the vibration acceleration power spectrum n -δ rms ; In the random vibration response spectrum calculation module, the measured spectrum is used as the basic acceleration power spectrum density Calculate different natural frequencies f according to the calculation formula n Next The root mean square δ of the relative displacement rms , and obtain the random vibration response spectrum f of the measured spectrum n -δ rms ; The specific calculation formula is: in, G A (f) is the power spectrum density of relative displacement; f is the excitation frequency; ζ is the critical damping ratio.

13. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 12, characterized in that: In the vibration acceleration power spectrum random vibration response spectrum calculation module and the measured spectrum random vibration response spectrum calculation module, the critical damping ratio ζ is taken as 0.

05.

14. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 13, characterized in that: In the vibration acceleration power spectrum random vibration response spectrum calculation module and the measured spectrum random vibration response spectrum calculation module, the step size of the excitation frequency f is 0.01 Hz.

15. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 14, characterized in that: In the vibration acceleration power spectrum random vibration response spectrum calculation module, as well as the measured spectrum random vibration response spectrum calculation module, the natural frequency f n The step size is 0.1Hz.

16. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 15, characterized in that: In the measured spectrum construction module, the characteristic frequencies of the measured spectrum include f a 、f b ,f1,f2,f3,…,f j ,in, f a is the starting frequency, usually 15Hz; f b is the termination frequency, and the cutoff frequency of the vibration acceleration power spectrum is taken; f1, f2, f3, …, f j is the peak frequency of each narrowband spectrum, corresponding to the peak frequency of each narrowband spectrum in the vibration acceleration power spectrum.

17. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 16, characterized in that: In the measured spectrum construction module, the bandwidth of each narrowband frequency spectrum of the measured spectrum is constructed, and 95% to 105% of the corresponding peak frequency in the vibration acceleration power spectrum is taken.

18. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 17, characterized in that: In the measured spectrum broadband spectrum and narrowband spectrum amplitude setting module, the amplitude G0 of the measured spectrum broadband spectrum is set, and the amplitudes G1, G2, G3, ..., G1 of the measured spectrum narrowband spectrum and G2 of the measured spectrum broadband spectrum are set. j .

19. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 18, characterized in that: In the random vibration response error calculation and judgment module between the measured spectrum and the vibration acceleration power spectrum, the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum in the measured spectrum and the vibration acceleration power spectrum, as well as the relative errors err1, err2, err3, ..., err j ; If the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err j If there is a value greater than the set error threshold, the amplitude of the corresponding spectrum in the measured spectrum is reset, and the measured spectrum random vibration response spectrum calculation module and the measured spectrum and vibration acceleration power spectrum random vibration response error calculation and judgment module are re-performed until the relative error err0 of the maximum vibration response amplitude caused by the broadband spectrum and the relative errors err1, err2, err3, ..., err4, caused by each narrowband spectrum are j There is no value greater than the set error threshold, thus the measured spectrum is obtained.

20. The measured spectrum conversion system of vibration acceleration power spectrum according to claim 19, characterized in that: In the random vibration response error calculation and judgment module between the measured spectrum and the vibration acceleration power spectrum, the error threshold is set to 2%.

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