Sample selection and determination method for supplementary verification of captive vibration test

Abstract

The invention provides a sample selection and determination method for supplementary verification of a hang-off vibration test, and the method specifically comprises the steps: obtaining the maximum vibration equivalent time tmax of the reliability test of a plurality of vibration magnitudes and the acceleration power spectrum psdmax of the maximum vibration magnitude test for a sample A subjected to a plurality of vibration tests and a sample B subjected to a plurality of reliability tests; the acceleration power spectrum and the duration of each full-order vibration test and the maximum vibration equivalent time t'max of the vibration test are obtained; respectively comparing the acceleration power spectrum, the duration time and the maximum vibration equivalent time t'max of each vibration test of the sample A with the psdmax and the tmax of the reliability test of the sample B in a low-frequency vibration region, so as to realize the selection of the sample A or the sample B. Therefore, the existing sample, namely the sample A or the sample B, can be reasonably selected, the selected sample A or the sample B is improved and then subjected to supplementary verification of the hanging vibration test again, the test verification efficiency is improved, and the cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental adaptability, and in particular relates to a sample selection and determination method for supplementing and verifying a flying vibration test. Background Art

[0002] Aircraft are generally affected by the vibration environment during use, so aircraft flight vibration tests will be carried out during the development and identification process. In addition, in order to verify the aircraft's flight reliability, aircraft flight reliability tests will also be carried out.

[0003] Taking into account the life of the aircraft, the aircraft flight vibration test and the flight reliability test will use different aircraft as samples for testing. The aircraft sample for the flight vibration test is sample A, and the aircraft sample for the flight reliability test is sample B. Since the flight vibration test takes a long time, which can reach several hours or even dozens of hours, and the vibration value of the flight vibration test is larger than that of the reliability test, sample A is more likely to fail during the test. At this time, it is necessary to analyze the cause of the failure and improve the aircraft. The improved aircraft needs to be re-tested for flight vibration for additional verification. Since most of the time, the improvements are only local design improvements of the aircraft, the flight vibration tests that have been completed on other parts of the aircraft are valid. If a brand new aircraft is selected for re-testing for additional verification, the cost is high and the cycle is long. Summary of the invention

[0004] The present invention aims to solve at least one of the problems existing in the prior art.

[0005] To this end, the present invention provides a sample selection and determination method for supplementary verification of the flying vibration test, which can reasonably select existing samples, namely sample A or sample B, and improve the selected sample A or sample B and re-perform the flying vibration test (hereinafter referred to as vibration test) for supplementary verification, thereby improving the test verification efficiency and reducing costs.

[0006] The technical solution of the present invention is:

[0007] A method for selecting and determining samples for supplementary verification of the flying vibration test is as follows:

[0008] Step 1: for sample A subjected to multiple vibration tests and sample B subjected to multiple reliability tests, respectively obtain vibration acceleration power spectral density data of the multiple vibration tests and vibration acceleration power spectral density data of the multiple reliability tests;

[0009] Step 2: According to the vibration conditions of the reliability test, the maximum acceleration power spectrum psdtjmax of the reliability test of multiple vibration levels and the maximum vibration equivalent time tmax of the reliability test are obtained; and according to the vibration acceleration power spectrum density data of the reliability test, the acceleration power spectrum psdmax of the vibration level corresponding to the maximum vibration level test, i.e. psdtjmax, is obtained;

[0010] According to the vibration acceleration power spectrum density data of the vibration test, the acceleration power spectrum, duration and maximum vibration equivalent time t'max of the vibration test at each full-scale level are obtained;

[0011] Step 3: Compare the vibration measurement results of each vibration test of sample A with the psdmax and tmax of the reliability test of sample B in the low-frequency vibration area:

[0012] If the acceleration power spectrum of any vibration test exceeds the psdmax of the reliability test and the duration exceeds the tmax of the reliability test, or the acceleration power spectra of all vibration tests exceed the psdmax of the reliability test and the sum of the durations of all vibration tests exceeds the tmax of the reliability test, then sample B that undergoes the reliability test shall be selected for a supplementary verification test; if the above two conditions are not met, then the cumulative vibration comparison shall continue: if the t'max of the vibration test is greater than the tmax of the reliability test, then sample B that undergoes the reliability test shall be selected for a subsequent supplementary verification test, otherwise sample A that undergoes the vibration test shall be selected for a subsequent supplementary verification test.

[0013] Furthermore, in step 2, the maximum vibration equivalent time tmax of the reliability test is calculated as follows:

[0014] Since the vibration environment in the reliability test is composed of multiple vibration levels with the same vibration spectrum, the acceleration power spectra corresponding to the test conditions of multiple vibration levels are psdtj1, psdtj2, ..., psdtjn, and the corresponding durations are t1, t2, ..., tn, among which the largest acceleration power spectrum is psdtjmax; the vibration equivalent time t corresponding to each vibration level is calculated according to the following formula 等效 :

[0015] t 等效 = tn*(psdtjmax / psdtjn) 4 Formula (1)

[0016] After accumulating the vibration equivalent time of all reliability tests, the maximum vibration equivalent time tmax of the reliability test is obtained.

[0017] Furthermore, in step 2, the maximum vibration equivalent time t'max of the vibration test is calculated as follows:

[0018] According to the vibration acceleration power spectrum density data of the vibration test, the acceleration power spectra of each full-scale vibration test are obtained, namely psda, psdb, ..., psdm, and the corresponding durations are ta, tb, ..., tm, respectively, where the maximum acceleration power spectrum is recorded as psdmax'; the vibration equivalent time t' of each full-scale vibration test is calculated according to formula (2): 等效 :

[0019] t' 等效 = tm*(psdmax' / psdm) 4 Formula (2)

[0020] After accumulating the vibration equivalent time of all vibration tests, the maximum vibration equivalent time t'max of the vibration test is obtained.

[0021] Furthermore, in step three, the lower limit of the vibration frequency in the low-frequency vibration area is the starting frequency of the vibration condition, and the upper limit of the vibration frequency in the low-frequency vibration area is the larger value of the first-order natural frequency of the aircraft and 100 Hz.

[0022] Furthermore, the specific steps of step one are:

[0023] Step 1-1, according to the simulation results of the vibration test or previous test experience, the position of the stiffness mutation section of the aircraft is used as the measurement point position of the vibration test and reliability test;

[0024] Step 1-2, select sample A as the test sample for each vibration test of the aircraft, install a vibration sensor on sample A according to the measurement point position determined in step 1-1, and perform multiple vibration tests on sample A, each vibration test is a full-scale test;

[0025] Vibration measurement is performed in each vibration test, and the measured vibration acceleration time domain data or vibration acceleration power spectrum density data is saved;

[0026] If the measured data is vibration acceleration time domain data, then the acceleration power spectrum density analysis is performed on the vibration acceleration time domain data to obtain vibration acceleration power spectrum density data;

[0027] Step 1-3, select sample B as the test sample for the aircraft reliability test, install a vibration sensor on sample B according to the measurement point position determined in step 1-1, and perform multiple reliability tests on sample B, wherein the vibration spectra of the multiple reliability tests are the same but the vibration magnitudes are different;

[0028] Vibration measurement is performed in each reliability test, and the measured vibration acceleration time domain data or vibration acceleration power spectrum density data is saved;

[0029] If the measured data is vibration acceleration time domain data, acceleration power spectrum density analysis is performed on the vibration acceleration time domain data to obtain vibration acceleration power spectrum density data.

[0030] Furthermore, when performing vibration measurement in each vibration test, the sampling frequency fs of the vibration measurement shall not be less than 2.56 times the highest frequency of the vibration test and shall not be less than 5120 Hz;

[0031] When vibration measurement is performed in each reliability test, the sampling frequency fs of the vibration measurement shall not be less than 2.56 times the highest frequency of the reliability test and shall not be less than 5120 Hz.

[0032] Furthermore, when the vibration acceleration time domain data is subjected to acceleration power spectrum density analysis, the number of Fourier transform points used should be no less than the ratio of the sampling frequency fs to the minimum frequency resolution df, and the minimum frequency resolution should be no greater than 2.5 Hz.

[0033] Furthermore, since sample A is damaged during the vibration test, before the selected sample A or sample B is subjected to a supplementary verification test, local improvements are made to the selected sample A or sample B at the corresponding damaged position.

[0034] By applying the above technical solution, the present invention has the following beneficial effects:

[0035] (1) For supplementary test verification after failure in aircraft vibration test and local improvement design, the present invention can give priority to using existing test samples (i.e., sample A for vibration test and sample B for reliability test) for supplementary test verification. On the issue of how to select sample A and sample B, the present invention proposes for the first time a specific method of selecting and determining test samples for supplementary test verification by performing vibration measurement in each test and comparing equivalent vibration responses in key frequency bands. This method can shorten the test verification cycle and reduce the cost of test samples. The results can be extended to various supplementary verification vibration tests of aircraft that are in flight for a long time.

[0036] (2) The present invention uses the maximum acceleration power spectrum and the maximum vibration equivalent time for comparison, which clarifies a quantitative comparison method for evaluating the structural fatigue damage accumulation between different test pieces and can obtain clear evaluation conclusions.

[0037] (3) The method of calculating the vibration equivalent time of the present invention takes into account the characteristics that the duration of large-scale tests accounts for a small proportion and the duration of small-scale tests accounts for a large proportion in reliability tests, and takes into account the vibration fatigue damage accumulated by multiple vibration magnitude tests in the reliability test. The analysis result is compared with the vibration test measurement result, and the comparison result is more accurate.

[0038] (4) The present invention selects the low-frequency vibration area as a comparison element. According to the rule that the structural damage of an aircraft is mainly caused by low-frequency vibration, by comparing the vibration accumulation in the low-frequency area, it is determined which test piece has more serious structural vibration fatigue damage.

[0039] (5) The present invention uses the location of the aircraft's stiffness mutation section as the measurement point location for vibration tests and reliability tests, which can obtain the vibration response of the area of ​​the aircraft that is most susceptible to damage due to vibration stress, providing a basis for the subsequent implementation of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 is a flow chart of the present invention;

[0042] Figure 2 It is the power spectrum density curve of vibration acceleration at the WB position of the first vibration test;

[0043] Figure 3 It is the power spectrum density curve of vibration acceleration at the WC position of the first vibration test;

[0044] Figure 4 It is the power spectrum density curve of vibration acceleration at the WB position of the second vibration test;

[0045] Figure 5 It is the power spectrum density curve of vibration acceleration at the WC position of the second vibration test;

[0046] Figure 6 It is the acceleration power spectrum density curve at the WB position of the maximum vibration level test of the reliability test;

[0047] Figure 7 This is the acceleration power spectrum density curve at the WC position of the maximum vibration level test of the reliability test. DETAILED DESCRIPTION

[0048] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0051] Embodiment 1:

[0052] This embodiment provides a method for selecting and determining samples for a supplementary verification vibration test. The method is a method for selecting sample A or sample B as a sample for a subsequent supplementary verification vibration test for sample A that fails during the aircraft vibration test. The method is as follows:

[0053] Step 1: for sample A subjected to multiple vibration tests and sample B subjected to multiple reliability tests, respectively obtain vibration acceleration power spectral density data of the multiple vibration tests and vibration acceleration power spectral density data of the multiple reliability tests;

[0054] Step 2: According to the vibration conditions of the reliability test, the maximum acceleration power spectrum psdtjmax of the reliability test of multiple vibration levels and the maximum vibration equivalent time tmax of the reliability test are obtained; and according to the vibration acceleration power spectrum density data of the reliability test, the acceleration power spectrum psdmax of the maximum vibration level (i.e., the vibration level corresponding to psdtjmax) test is obtained;

[0055] According to the vibration acceleration power spectrum density data of the vibration test, the acceleration power spectrum, duration and maximum vibration equivalent time t'max of the vibration test at each full-scale level are obtained;

[0056] Step 3: Compare the vibration measurement results of each vibration test of sample A (i.e., the acceleration power spectrum, duration and maximum vibration equivalent time t'max of each vibration test) with the measurement results of the maximum vibration magnitude test of the reliability test of sample B (i.e., the acceleration power spectrum psdmax) and the maximum vibration equivalent time tmax of the reliability test in the low-frequency vibration area:

[0057] If the acceleration power spectrum of any vibration test exceeds the psdmax of the reliability test and the duration exceeds the tmax of the reliability test, or the acceleration power spectra of all vibration tests exceed the psdmax of the reliability test and the sum of the durations of all vibration tests exceeds the tmax of the reliability test, then sample B that undergoes the reliability test shall be selected for a supplementary verification test; if the above two conditions are not met, then the cumulative vibration comparison shall continue: if the t'max of the vibration test is greater than the tmax of the reliability test, then sample B that undergoes the reliability test shall be selected for a subsequent supplementary verification test, otherwise sample A that undergoes the vibration test shall be selected for a subsequent supplementary verification test.

[0058] Embodiment 2:

[0059] This embodiment provides a method for selecting and determining samples for supplementary verification of the flying vibration test based on embodiment 1. Figure 1 The specific steps of the determination method are as follows:

[0060] The first step is to determine the measurement point locations for each vibration test and reliability test of the aircraft:

[0061] According to the simulation results of vibration tests or previous test experience, the parts prone to damage are used as the measurement points for vibration tests and reliability tests, generally near the section with sudden change in stiffness (such as the connection between cabin sections);

[0062] The second step is to perform vibration measurements on each vibration test of the aircraft:

[0063] Select sample A as the test sample for each vibration test of the aircraft, install a vibration sensor on sample A according to the measurement point position determined in the first step, and perform multiple vibration tests on sample A, each vibration test is a full-scale test;

[0064] Vibration measurement is performed in each vibration test. The sampling frequency fs of the vibration measurement is not less than 2.56 times the highest frequency of the vibration test, generally not less than 5120Hz. The measured vibration acceleration time domain data or vibration acceleration power spectrum density data is saved;

[0065] If the measured data is vibration acceleration time domain data, it is necessary to perform acceleration power spectrum density analysis on the vibration acceleration time domain data to obtain vibration acceleration power spectrum density data. The specific analysis method is:

[0066] Select the vibration acceleration time domain data in the vibration test, and perform acceleration power spectrum density analysis on the vibration acceleration time domain data. The number of Fourier transform points used in the analysis should not be less than the ratio of the sampling frequency fs to the minimum frequency resolution df. The minimum frequency resolution is generally not greater than 2.5Hz.

[0067] The measurement results of the vibration tests at each full-scale level are as follows: the acceleration power spectra are psda, psdb, ..., psdm, and the corresponding durations are ta, tb, ..., tm;

[0068] The third step is to conduct vibration measurement for the aircraft reliability test:

[0069] Select sample B as the test sample for the aircraft reliability test. According to the measurement point position determined in the first step, install a vibration sensor on sample B, and perform multiple reliability tests on sample B. The vibration spectra of the multiple reliability tests are the same, but the vibration magnitudes are different. The test conditions of the reliability tests with different vibration magnitudes are: the acceleration power spectra are psdtj1, psdtj2, ..., psdtjn, and the corresponding durations are t1, t2, ..., tn, respectively. The maximum acceleration power spectrum is recorded as psdtjmax, and the vibration magnitude corresponding to psdtjmax is the maximum vibration magnitude.

[0070] Vibration measurement is carried out in each reliability test. The sampling frequency fs of vibration measurement shall not be less than 2.56 times of the highest frequency of the reliability test, generally not less than 5120Hz, and the measured vibration acceleration time domain data or vibration acceleration power spectrum density data shall be saved;

[0071] If the measured data is vibration acceleration time domain data, it is necessary to perform acceleration power spectrum density analysis on the vibration acceleration time domain data to obtain vibration acceleration power spectrum density data. The specific analysis method is:

[0072] Select the vibration acceleration time domain data in the reliability test, and perform acceleration power spectrum density analysis on the vibration acceleration time domain data. The number of Fourier transform points used in the analysis should not be less than the ratio of the sampling frequency fs to the minimum frequency resolution df. The minimum frequency resolution is generally not greater than 2.5Hz.

[0073] The measurement results of the reliability test of the maximum vibration level (i.e. the vibration level corresponding to psdtjmax) obtained by measurement: acceleration power spectrum psdmax, psdmax is close to psdtjmax;

[0074] The fourth step is to perform vibration time equivalence on the reliability test:

[0075] Since the vibration environment in the reliability test is generally composed of multiple vibration levels with the same vibration spectrum, the acceleration power spectra corresponding to the test conditions of multiple vibration levels are psdtj1, psdtj2, ..., psdtjn, and the corresponding durations are t1, t2, ..., tn, among which the largest acceleration power spectrum is psdtjmax; the vibration equivalent time t corresponding to each vibration level is calculated according to the following formula 等效 :

[0076] t 等效 = tn*(psdtjmax / psdtjn) 4 Formula (1)

[0077] The acceleration power spectrum, duration and vibration equivalent time t corresponding to multiple vibration levels are calculated. 等效 Draw into Table 1:

[0078] Table 1

[0079] Acceleration power spectrum Duration Vibration equivalent time psdtj1 t1 <![CDATA[t1*(psdtjmax / psdtj1) 4 ]]> psdtj2 t2 <![CDATA[t2*(psdtjmax / psdtj2) 4 ]]> …… …… …… psdj tn <![CDATA[tn*(psdtjmax / psdtjn) 4 ]]>

[0080] After accumulating all the vibration equivalent times in Table 1, the maximum vibration equivalent time tmax of the reliability test is obtained.

[0081] Step 5: Determine the vibration comparison frequency range:

[0082] In order to compare the reliability test with the vibration test, the low-frequency vibration area is used as the vibration comparison frequency range, mainly to assess the impact of structural damage. The lower limit of the vibration frequency in the low-frequency vibration area is the starting frequency of the vibration condition, and the upper limit of the vibration frequency in the low-frequency vibration area is the larger value of the first-order natural frequency of the aircraft and 100Hz.

[0083] Step 6: Preliminary comparison of vibration conditions:

[0084] The vibration measurement results of each vibration test of sample A are compared with the measurement results of the maximum vibration level (i.e., the vibration level corresponding to psdtjmax) and the vibration equivalent time t of the reliability test of sample B. 等效 Compare in the low-frequency vibration area. If the vibration magnitude of any vibration test (i.e., acceleration power spectrum psdm) exceeds psdmax of the reliability test, and the duration tm exceeds tmax of the reliability test, or the vibration magnitudes of all vibration tests (i.e., acceleration power spectrum psda, psdb, ..., psdm) exceed psdmax of the reliability test, and the cumulative duration of each vibration test (ta+tb+ ...+tm) exceeds tmax of the reliability test, then select sample B for the reliability test for supplementary verification test; if direct evaluation is not possible, proceed to step 7;

[0085] Step 7: Comparison of cumulative vibration:

[0086] Since the acceleration power spectra of the low-frequency vibration measurement results of each full-scale vibration test are psda, psdb, ..., psdm, and the corresponding durations are ta, tb, ..., tm, the maximum acceleration power spectrum is recorded as psdmax'; the vibration equivalent time t' of each full-scale vibration test is calculated according to the following formula 等效 :

[0087] t' 等效 = tm*(psdmax' / psdm) 4 Formula (2)

[0088] The acceleration power spectrum, duration and vibration equivalent time t' of each full-scale vibration test 等效 Draw into Table 2:

[0089] Table 2

[0090] Acceleration power spectrum Duration Vibration equivalent time psd ta <![CDATA[ta*(psdmax’ / psda) 4 ]]> psdb tb <![CDATA[tb*(psdmax’ / psdb) 4 <!-- 6 -->]]> …… …… …… psdm tm <![CDATA[tm*(psdmax’ / psdm) 4 ]]>

[0091] After accumulating all vibration equivalent times in Table 2, the maximum vibration equivalent time t'max of the vibration test is obtained. If the t'max of the vibration test is greater than the tmax of the reliability test, the sample B for the reliability test is selected for the subsequent supplementary verification test, otherwise the sample A for the vibration test is selected for the subsequent supplementary verification test;

[0092] Among them, since sample A is damaged during the vibration test, before the selected sample A or sample B is subjected to a supplementary verification test, it is necessary to perform local improvements on the selected sample A or sample B at the corresponding damaged position.

[0093] Embodiment 3:

[0094] This embodiment provides an application example of a sample selection and determination method for supplementary verification of the flying vibration test on the basis of embodiment 2. The specific method of this example is as follows:

[0095] The first step is to determine the measurement point locations for each vibration test and reliability test of the aircraft:

[0096] There are two stiffness mutation sections in the aircraft, which are marked as WB and WC. These two locations are used as the measurement points for vibration test and reliability test.

[0097] The second step is to perform vibration measurements on each vibration test of the aircraft:

[0098] Sample A is selected as the test sample for each vibration test of the aircraft, vibration sensors are installed on sample A at the WB and WC positions, and a vibration test is performed on sample A; in this embodiment, two full-scale vibration tests are performed on sample A, the duration of the first vibration test is 10 hours, and the duration of the second vibration test is 9 hours;

[0099] In each vibration test, vibration measurement is performed, the sampling frequency fs is 5120 Hz, and the measured vibration acceleration time domain data is saved;

[0100] The vibration acceleration time domain data in the vibration test is selected for acceleration power spectrum density analysis. The number of Fourier transform points used in the analysis should not be less than the ratio of the sampling frequency fs to the minimum frequency resolution df. The minimum frequency resolution is generally not greater than 2.5Hz.

[0101] In the first vibration test of this embodiment, the acceleration power spectrum density curves at the WB and WC positions are shown in the attached Figure 2-Figure 3 ; In the second vibration test, the acceleration power spectrum density curves at the WB and WC positions are shown in the attached Figure 4-Figure 5 .

[0102] The third step is to conduct vibration measurement for the aircraft reliability test:

[0103] Select sample B as the test sample for the aircraft reliability test, install vibration sensors at the WB and WC positions of sample B, and perform a reliability test on sample B; in this embodiment, perform two vibration tests on sample B with the same vibration spectrum and different vibration magnitudes;

[0104] In each reliability test, vibration measurement is carried out, the sampling frequency fs is 5120Hz, and the measured vibration acceleration power spectrum density data is saved; the acceleration power spectrum density curves of WB and WC are shown in the attached Figure 6-Figure 7 , Figure 6 and Figure 7 It is the data measured in the maximum vibration level test in the reliability test;

[0105] The fourth step is to perform vibration time equivalence on the reliability test:

[0106] Since the vibration environment in the reliability test in this embodiment is composed of two vibration levels with the same vibration spectrum type, the acceleration power spectrum density of any frequency point is compared. For example, at a frequency of 20 Hz, the acceleration power spectra corresponding to the two vibration level test conditions are psdtj1 and psdtj2, respectively, and the corresponding durations are t1 and t2, wherein the maximum acceleration power spectrum is recorded as psdtjmax=psd1; the vibration equivalent time of the two vibration levels is calculated respectively according to formula (1), and after accumulating the vibration equivalent time, the maximum vibration equivalent time tmax=14.6h of the reliability test is obtained, as shown in Table 3:

[0107] Table 3

[0108]

[0109] Step 5: Determine the vibration comparison frequency range:

[0110] The low-frequency vibration region is used as the vibration comparison frequency range, the lower limit of the vibration frequency in the low-frequency vibration region is 20 Hz, 20 Hz is the starting frequency of the vibration condition, and the upper limit of the vibration frequency in the low-frequency vibration region is 100 Hz;

[0111] Step 6: Preliminary comparison of vibration conditions:

[0112] The vibration measurement results of each vibration test of sample A were compared with the maximum vibration level measurement results of the reliability test of sample B (i.e., the vibration level corresponding to psdtjmax) in the low-frequency vibration area. Since the vibration response of the vibration test at 20 Hz is the most prominent, the power spectrum density of the vibration acceleration at this frequency point is used for comparison. The comparison results are shown in Table 4.

[0113] Table 4 Low frequency vibration value comparison table

[0114]

[0115] Among them, the vibration response of the reliability test of sample B in the table corresponds to the measured value of the maximum vibration level psdtjmax, and psdtj1 and psdtj2 of the reliability test are test conditions used to stimulate the aircraft, and the measured values ​​may be inconsistent with the test conditions.

[0116] Therefore, the vibration responses of the two vibration tests exceeded the vibration response of the maximum vibration level reliability test (i.e., the test with a vibration level of psdtjmax). The two vibration test times were 10 h and 9 h respectively, and the cumulative time exceeded the tmax of the reliability test (13+1.6=14.6 h). Therefore, sample B, which was used for the reliability test, was selected for the subsequent supplementary verification test.

[0117] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0118] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0119] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for selecting and determining samples for supplementary verification of flying vibration test, characterized in that: The determination method is: Step 1: for sample A subjected to multiple vibration tests and sample B subjected to multiple reliability tests, respectively obtain vibration acceleration power spectral density data of the multiple vibration tests and vibration acceleration power spectral density data of the multiple reliability tests; Step 2: According to the vibration conditions of the reliability test, the maximum acceleration power spectrum psdtjmax of the reliability test of multiple vibration levels and the maximum vibration equivalent time tmax of the reliability test are obtained; and according to the vibration acceleration power spectrum density data of the reliability test, the acceleration power spectrum psdmax of the vibration level corresponding to the maximum vibration level test, i.e. psdtjmax, is obtained; According to the vibration acceleration power spectrum density data of the vibration test, the acceleration power spectrum, duration and maximum vibration equivalent time t'max of the vibration test at each full-scale level are obtained; Step 3: Compare the vibration measurement results of each vibration test of sample A with the psdmax and tmax of the reliability test of sample B in the low-frequency vibration area: If the acceleration power spectrum of any vibration test exceeds the psdmax of the reliability test and the duration exceeds the tmax of the reliability test, or the acceleration power spectra of all vibration tests exceed the psdmax of the reliability test and the sum of the durations of all vibration tests exceeds the tmax of the reliability test, then sample B that undergoes the reliability test shall be selected for a supplementary verification test; if the above two conditions are not met, then the cumulative vibration comparison shall continue: if the t'max of the vibration test is greater than the tmax of the reliability test, then sample B that undergoes the reliability test shall be selected for a subsequent supplementary verification test, otherwise sample A that undergoes the vibration test shall be selected for a subsequent supplementary verification test.

2. A method for selecting and determining samples for supplementary verification of flying vibration test according to claim 1, characterized in that: In step 2, the maximum vibration equivalent time tmax of the reliability test is calculated as follows: Since the vibration environment in the reliability test is composed of multiple vibration levels with the same vibration spectrum, the acceleration power spectra corresponding to the test conditions of multiple vibration levels are psdtj1, psdtj2, ..., psdtjn, and the corresponding durations are t1, t2, ..., tn, among which the largest acceleration power spectrum is psdtjmax; the vibration equivalent time t corresponding to each vibration level is calculated according to the following formula 等效 : t 等效 = tn*(psdtjmax / psdtjn) 4 Formula(1) After accumulating the vibration equivalent time of all reliability tests, the maximum vibration equivalent time tmax of the reliability test is obtained.

3. A method for selecting and determining samples for supplementary verification of flying vibration test according to claim 1, characterized in that: In step 2, the maximum vibration equivalent time t'max of the vibration test is calculated as follows: According to the vibration acceleration power spectrum density data of the vibration test, the acceleration power spectra of each full-scale vibration test are obtained, namely psda, psdb, ..., psdm, and the corresponding durations are ta, tb, ..., tm, respectively, where the maximum acceleration power spectrum is recorded as psdmax'; the vibration equivalent time t' of each full-scale vibration test is calculated according to formula (2): 等效 : t' 等效 = tm*(psdmax' / psdm) 4 Formula (2) After accumulating the vibration equivalent time of all vibration tests, the maximum vibration equivalent time t'max of the vibration test is obtained.

4. A method for selecting and determining samples for supplementary verification of flying vibration test according to claim 1, characterized in that: In step three, the lower limit of the vibration frequency in the low-frequency vibration area is the starting frequency of the vibration condition, and the upper limit of the vibration frequency in the low-frequency vibration area is the larger value of the first-order natural frequency of the aircraft and 100 Hz.

5. A method for selecting and determining samples for supplementary verification of flying vibration test according to claim 1, characterized in that: The specific steps of step one are: Step 1-1, according to the simulation results of the vibration test or previous test experience, the position of the stiffness mutation section of the aircraft is used as the measurement point position of the vibration test and reliability test; Step 1-2, select sample A as the test sample for each vibration test of the aircraft, install a vibration sensor on sample A according to the measurement point position determined in step 1-1, and perform multiple vibration tests on sample A, each vibration test is a full-scale test; Vibration measurement is performed in each vibration test, and the measured vibration acceleration time domain data or vibration acceleration power spectrum density data is saved; If the measured data is vibration acceleration time domain data, then the acceleration power spectrum density analysis is performed on the vibration acceleration time domain data to obtain vibration acceleration power spectrum density data; Step 1-3, select sample B as the test sample for the aircraft reliability test, install a vibration sensor on sample B according to the measurement point position determined in step 1-1, and perform multiple reliability tests on sample B, wherein the vibration spectra of the multiple reliability tests are the same but the vibration magnitudes are different; Vibration measurement is performed in each reliability test, and the measured vibration acceleration time domain data or vibration acceleration power spectrum density data is saved; If the measured data is vibration acceleration time domain data, acceleration power spectrum density analysis is performed on the vibration acceleration time domain data to obtain vibration acceleration power spectrum density data.

6. A method for selecting and determining samples for supplementary verification of flying vibration test according to claim 5, characterized in that: When performing vibration measurement in each vibration test, the sampling frequency fs of the vibration measurement shall not be less than 2.56 times the highest frequency of the vibration test and shall not be less than 5120 Hz; When vibration measurement is performed in each reliability test, the sampling frequency fs of the vibration measurement shall not be less than 2.56 times the highest frequency of the reliability test and shall not be less than 5120 Hz.

7. A method for selecting and determining samples for supplementary verification of flying vibration test according to claim 6, characterized in that: When performing acceleration power spectrum density analysis on the vibration acceleration time domain data, the number of Fourier transform points used should not be less than the ratio of the sampling frequency fs to the minimum frequency resolution df, and the minimum frequency resolution should not be greater than 2.5 Hz.

8. A method for selecting and determining samples for supplementary verification of a flying vibration test according to any one of claims 1 to 6, characterized in that: Since sample A is damaged during the vibration test, before the selected sample A or sample B is subjected to the supplementary verification test, local improvements are made to the selected sample A or sample B at the corresponding damaged position.

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