This standard is equivalent to IEC 60068-2-64: 1993. Two test methods are provided in the standard to determine the ability of the test sample to withstand the specified broadband random vibration. This standard is only used for electrical and electronic products, but is not limited to this. GB/T 2423.56-2006 Environmental testing for electrical and electronic products Part 2: Test method Test Fh: Broadband random vibration (digital control) and guidance GB/T2423.56-2006 Standard download decompression password: www.bzxz.net
This standard is equivalent to IEC 60068-2-64: 1993. Two test methods are provided in the standard to determine the ability of the test sample to withstand the specified broadband random vibration. This standard is only used for electrical and electronic products, but is not limited to this.

ICS 19.020
National Standard of the People's Republic of China
GB/T 2423.56—2006/IEC 60068-2-64:1993Envirunmental testing for electric and electronic products-Part 2: Test methods-
Test Fh: Vibration, broad-band random(digital control)and guidance(IEC 60068-2-64:1993, IDI)
2006-11-08 Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of China
2007-04-01 Implementation
Normative references
Test requirements
Severity level
Pretreatment
Initial test
Final test -
11 Information to be given in the relevant specifications
Appendix A (Normative Appendix) Vibration response check Appendix B (Informative Appendix)
Appendix C (Informative Appendix)
Conversion between percentage and dH
Tolerance band of instantaneous acceleration value distribution
Tolerance of acceleration spectral density Difference limit
Gaussian (normal) probability density function
Signal clipping diagram
Non-Gaussian probability density function after clipping
GB/T2423.56-2006/IEC60068-2-64:199317
Relationship between statistical accuracy and degree of freedom of acceleration spectrum density at different confidence levelsFigure 6
Relationship between acceleration spectrum density and rate
Flow chart of random vibration test with competition
Regularized transmissibility factor of sputtering device
GB/T2423.56—2006/IEC60068-2-64:1993GB/T2423 "Environmental testing for electric and electronic products Part 2: Test methods" series of standards are divided into the following parts according to the test methods. This part is Part 56 of the GB/T2423 series of standards. This part is equivalent to IEC60068-2-64:1993 "Environmental testing Part 2: Test methods Test Fh: Broadband random vibration (numerical control) and guidance" (English version), but the following editorial changes are made according to the provisions of 4.2b) and 5.2 of GB/T20000.2-2001 Standardization Work Guide Part 2: Rules for the adoption of international standards: a) The term "this part of IEC60068" is changed to "this part of GB/T2423" or "this part"; b) The decimal point "\" is used instead of the comma " as a decimal point; the foreword of the international standard is deleted:
d) In order to be consistent with the names of other parts of GB/T2423, this part is changed to the current name. Appendix A of this part is a normative appendix, and Appendix B and Appendix C are informative appendices. This part is proposed by the China Electrical Engineering Association.
This part is under the jurisdiction of the National Technical Committee for Environmental Standardization of Electrical and Electronic Products (SAC/TC8). This part was drafted by Guangzhou University, the Fifth Electronic Research Institute of the Ministry of Information Industry, Shanghai Electronic Instrument Standard and Metrology Testing Institute, Beijing University of Aeronautics and Astronautics, the 301st Research Institute of Aviation Industry Corporation, Beijing Haidian Zhongyuan Micro Instrument Company, and Suzhou Test Instrument Factory. The main drafters of this part are: Xu Zhonggen, Ji Chunyang, Lu Zhaoming, Wang Deyu, Xu Ming, Xu Liyi, Zhang Yue, Ren Min, Yang Zequn, and Du Xueying. GB/T2423.56—2006/IEC60068-2-64;1993 Introduction
The broadband random vibration test standard is generally applicable to electrical and electronic products that may be subjected to random vibration. The test method specified in this part is based on digital control of random vibration. If required by relevant specifications, this part allows appropriate adjustments to the test method to apply to test samples of other types of products. This part replaces the existing analog broadband random vibration test method (Test Fd, GB/T2423.11-1982 GB/T 2423.14-1982).
It should be noted that random vibration testing is a complex process that requires a considerable understanding of the basic principles and techniques of the test, and considerable experience in process judgment during the test. Compared with most other tests, test Fh is not based on deterministic techniques but on statistical techniques. Therefore, the broadband random vibration test is described in terms of probability and statistical average. Appendix A (normative appendix) gives the requirements for vibration response inspection. Chapter 11 of this part lists in detail the information that the compiler of the relevant specifications should provide when using this test. Appendix B (informative appendix) gives the guidelines for this test. Appendix C (informative appendix) is for reference to the relevant chapters and gives the conversion between the reference value (expressed in B or percentage) and its alternative value.
1 Scope
GB/T2423.56—2006/IEC60068-2-64:1993 Environmental testing for electric and electronic products
Part 2: Test methods
Test Fh: Broadband random vibration (numerically controlled) and guidance This part provides two standard test methods (method 1 and method 2) to determine the ability of the test sample to withstand the specified broadband random vibration. It cannot be considered that one test method is more severe than the other test method. The difference is mainly that test method 2 provides more information to quantify the test applied, so it has better reproducibility. This part also reveals the stress accumulation effect and specific mechanical property degradation caused by random vibration, so as to use this information and related specifications to assess the acceptability of the test sample. Sometimes, this part is also used to prove the mechanical environmental adaptability of the sample and/or study their dynamic characteristics.
This part applies to samples that may be subjected to random vibration during transportation or working environment, such as in aircraft, spacecraft and land vehicles. It is mainly used for samples without packaging, and samples whose packaging is used as part of the sample itself during transportation. This part is applicable to electrical and electronic products, but is not limited to this. It can also be applied to products in its field. 2 Normative references
The clauses in the following documents become the clauses of this part through reference in this part. For all dated references, all subsequent amendments (excluding errors) or revisions are not applicable to this part. However, the parties to the agreement based on this part shall study whether the latest versions of these documents can be used. For all undated references, the latest versions shall apply to this part. GB/T 2298-1991 Mechanical vibration and shock terminology (idtISO 2041:1990) GB/T2421-1999 Environmental testing for electric and electronic products Part 1: General (idtIEC60068-1:1988) CB/T2423.10-1995 Environmental testing for electric and electronic products Part 2 Test methods Test Fc and guidance: Vibration (sinusoidal) (idtIEC 60068-2-6,1982)
GB/T2423.43-1995 Environmental testing for electric and electronic products Part 2 Test methods Requirements and guidance for the installation of components, equipment and other products in dynamic tests such as shock (Ea), collision (Eb), vibration (F and Fd) and steady-state acceleration (Ga) (idt IEC60068-2-47:1982)
GB/T4796 Classification of environmental parameters for electrical and electronic products and their severity classification (GB/T4796-2001, id1IFC6007211:1991)
[EC60050-301:1983 International Electrotechnical Terminology (IEV) Chapter 301: General Principles for Electronics IEC60050-302:1983 International Electrotechnical Terminology (IEV) Chapter 302: Electronic Measurement Measuring instruments [EC60050-303: 1983 International Electrotechnical Terminology (1FV) Chapter 303: Electronic measuring instruments (Advanced Edition) IEC60068 Environmental testing
IEC60068-2 Environmental testing Part 2: Test methods 3 Definitions
The terms used are in GB/T2298-1991 or 1EC60050 (301.302, 303): 1983 and GB/T2421-1999 or GB/T2423.10-1995. For the convenience of the reader, the definitions from the above standards but slightly different are included here, and their differences are pointed out.
In addition, the following additional terms and definitions also apply to this part. 1
GB/T 2423.56-2006/IEC60068-2-64:19933.1
-3 dB bandwidth B,- 3 dB bandwidth8.
The velocity width between two points in the frequency response function corresponding to 0.707 times the maximum response of a single resonance peak (see 4.3.6.2). [GB/T 2298-1991, revised]
Acceleration spectral density acceleration spectral density The mean value of the blood velocity signal per unit bandwidth passing through a narrow-band filter at the center frequency when the bandwidth tends to be dense and the averaging time tends to be zero penetration (see 4.3.4).
[GB/T 2298—1991, revised]
bias error
Systematic error caused by the use of limited frequency resolution to estimate the acceleration spectral density (see 4.3.6.2). 3.4
Check-point
The point on the tool, gripping table or sample used for signal detection should be as close as possible to the same fixed point and connected to it (see A.2.4.1).
Note 1: There should be enough check-points to meet the test requirements. Note 2: If the number of fixed points is less than or equal to 4, all of them shall be used as check-points. Otherwise, take 4 representative fixed points as measuring points in accordance with the provisions of the relevant specifications.
Note 3: In special cases, such as large or complex samples, if the measuring points cannot be close to the same fixed points, the relevant specifications shall have provisions. NOTE 4 When multiple small specimens are mounted on the same fixture or when a small specimen has several fixed points, a single detection point (reference point) may be selected to obtain the control signal. This signal is related to the fixture and not to the fixed point of the specimen. In this case, the lower resonance frequency of the actual fixture should be sufficiently higher than the upper limit of the test frequency. Control acceleration density Control acceleration spectral density The acceleration spectral density is measured at the reference point (see 4.3.3). 3.6 The control system loop includes the following operations: Control system loop Digitalization of the analog random signal at the reference point Performs the necessary data processing: Generates the updated analog random signal to the vibration system power amplifier (see B.134 3.7 Peak factor Crest factor The ratio of the peak value to the root mean square value (see 4.3.3). [GB/'r 2298—1991]
dampingratio
The ratio of actual damping to critical damping in a viscous damping system. 3.9
Distortion
Distortion:
×100(%)
. (1)
Where:
1The root mean square value of the velocity in the base signal: ur
The total root mean square value of all added gradients including 4, GB/T 2423.56—2006/1EC 60068-2-64:1993 (equivalent to the definition in Chapter 3 of GB/T2423.10—1995, different from the definition in GB/T2298—1991) 3.10
Clipping of drive signaldrivesignal Clipping Limitation of the instantaneous value of the drive signal (see 4.3.3). 3.11
Effective frequency rangeeffectivefrequencyrangeThe actual frequency range from the frequency below f: the front end of the ramp spectrum to the frequency above f: the rear end of the ramp spectrum (see Figure 2). 3.12
Error acceleration spectral densityerror
Error acceleration spectral densityThe difference between the acceleration spectral density value specified and the acceleration spectral density value achieved by the control. 3.13
Equalizationequalization
The process of minimizing the error in the velocity spectral density. 3.14
Final ramp spectrum
The part of the acceleration spectral density above F (see B.2.4). 3.15
Frequency resolution resolution The frequency of the acceleration spectral density is called the interval width and is expressed in Hertz. It is equal to the reciprocal of the sample record length in digital analysis. In a given frequency range, the number of spectral lines is equal to the number of intervals (see 4.3.6). 3.16
acceleration ofgravity
The acceleration due to the earth's gravity, which varies with altitude and geographical latitude (see 5.3). In this standard, g is rounded to 10 m/s. 3.17
indicated acceleration spectraldensityThe indicated value of the analyser affected by instrument error, random error and signal error (see 4.3.6). 3.18
initial slope
The part of the acceleration spectral density less than (see B.2.4). 3.19
instrament error
The error caused by each analog link of the control system and its input (see B.2.3.2). 3.20
Multipoint average controlmultipointcontrol, averagingControl acceleration spectrum density formed by arithmetic averaging of acceleration spectrum density of multiple detection points (see B.2.1.2). 3.21
Multipoint maximum controlmultipoint control, extralalControl acceleration spectrum density formed by the maximum value of acceleration spectrum density on the corresponding spectrum line of multiple detection points (see B.2.1.2). 3
GB/T2423.56—2006/IEC60068-2-64:19933.22
Preferred testing axesPreferred testing axes Select the three orthogonal axes corresponding to the weakest sample as far as possible according to actual conditions (see 8.1). 3.23
Random errorrandon error
Estimation error of acceleration spectrum density due to different actual averaging time and filter bandwidth limitation (see B.2.3.3). 3.24
record
a set of two equally spaced data points used for the calculation of the Fast Fourier Transform (see B.1). 3.25
reference point
a point selected from the test points whose signal is used for test control to meet the requirements of this standard. NOTE This point may be a pseudo-reference point (see A.2.4.2). 3.26
Ereproducibility
reproducibility the degree of agreement between the results of measurements of the same value of an inverse parameter made under the following different conditions: different test methods;
a different measuring instrument;
a different observer;
a different laboratory;
a different measuring time over a longer period of time!
a different instrument may be used. NOTE The term "reproducibility" may also be applied to situations where some of the above conditions are met. [IEC 60050(301,302,303)]
response points
response points
Points located at specific locations on the test specimen from which data are obtained for vibration response analysis. These points are not test points or reference points. (See A, 3.1).
root-mean-square value
fruot-mean-square value
The root-mean-square value of a single-valued function in the interval 2 is the square root of the average of the squares of the function values ​​in the interval (see 4.3.4).
[GB/T 2298—1991, revised]
Note: For this test method, the root-mean-square values ​​of acceleration, velocity and displacement can be calculated according to B.2.5, 3.29
standard deviation astandard deviation,a According to vibration theory, when the average value of the vibration amplitude is equal to 0, the standard deviation of the vibration is equal to the root mean square value. [GB/T2298—1991, revised]
Statistical accuracy
The ratio of the true value of the acceleration spectrum density to the indicated value of the acceleration spectrum density (see 4.3.5). 3.31
Statistical degrees of freedom
statistical degrees of freedom When the time averaging method is used to estimate the acceleration spectrum density of random data, the statistical degrees of freedom depend on the frequency resolution and the effective averaging time (see 4.3.5).
[GB/T 2298—1991, revised]
sweep cycle
GB/T2423.56—2006/IEC60068-2-64;1993 A reciprocating frequency sweep within a specified frequency range, for example 5 Hz-500 Hz-5 Hz (see A.2.5). GB/T 2423.10—1995
ftrue acceleration spectral density
The acceleration spectral density of a random wave acting on the test sample (see 4.3.6). 3.34
Window function windowfunction
A cut-off function used to reduce errors when processing weighted data (see 4.3.6.2). [GB/T 2298—1991]
4 Test requirements
4.1 General
When conducting the test, the entire vibration system including power amplifier, vibration generator, test tool, test sample and control system shall meet the necessary performance requirements.
This section provides two test methods.
Method 1 is usually applied to random vibration. However, the relevant specifications may also require a shake response check with sine or random vibration excitation before or before random vibration (see 8.2 and 8.6) Method 2 A vibration response check is performed with sine or random vibration excitation before the random vibration test to find the resonance with the narrowest 3 dB bandwidth. Under certain conditions, the relevant specifications may require additional vibration response checks (see 8,6). 4.2 Vibration response inspection
Test Fc (GB/T2423.10-1995) The requirements for sinusoidal excitation are specified in the normative Appendix A. The requirements for random excitation of random vibration test 4.3 are also specified in Appendix A. 4.3 Random vibration test
4.3.1 Basic motion
The relevant specifications should specify the basic motion of the fixed points of the test sample. These points should have roughly the same motion. Their basic motion should be linear motion and have random characteristics. Its instantaneous acceleration value should be normally (Gaussian) distributed. If it is difficult to achieve exactly the same motion at each point, multi-point control should be adopted.
4.3.2 Directional motion
The acceleration harmonic density of the inspection point measured on any axis perpendicular to the specified axis should not exceed 5dB of the specified value, and the corresponding acceleration root mean square value should not exceed 50% of the specified value of the basic motion. In special cases, such as small specimens, the specification shall limit the acceleration spectral density of the lateral motion to ensure that it does not exceed 3 dB of the fundamental motion. At certain frequencies or for specimens of large size or with a high centre of mass, it may be difficult to achieve these values. In such cases, the specification shall state that one of the following two applies: a) any lateral motion exceeding the values ​​given above shall be recorded in the test report; b) lateral motions known not to cause damage to the test specimen need not be monitored. 4.3.3 Distribution
Within the tolerance band given in Figure 1, the instantaneous acceleration values ​​at the reference point shall be distributed in a stationary (Gaussian) manner. For most random vibration test systems, the distribution will usually fall within the tolerance band. This should be verified during the routine calibration of the system (see B.2.2). If a virtual reference point is used for control, all test points used to construct the acceleration spectral density shall meet this distribution requirement. GB/T 2423.56—2006/IEC 60068-2-64: 1993 The relevant specification shall specify that the peak factor or clipping of the drive signal shall be at least 2.5. The acceleration waveform obtained from the test point shall be checked to ensure that the current signal includes a peak value not less than 2.5 times the specified RMS value. 4.3.4 Vibration tolerance
The tolerance of the velocity spectral density indication between the test point and the reference point in the required direction shall be within ±3 dB (see B.2.3.2) as shown in Figure 2. When method 2 is used, the relevant specification shall specify the maximum allowable deviation (see 8.1 and B, 2.3.4)
Within and f, the calculated or measured RMS value of the velocity shall be within ±10% of the RMS value of the specified acceleration spectral density. This value applies to single-point and multi-point control. At certain frequencies or for samples with large dimensions or high centroid, it may be difficult to achieve these values. In these cases, the relevant specifications should specify wider tolerances.
The initial and final slant spectra should be no less than +6 dB/oct and no less than -24 dB/oct, respectively (see B.2.4). 4.3.5 Statistical accuracy
Statistical accuracy is determined by the statistical degrees of freedom (N). The statistical degrees of freedom are calculated according to (2): Na = 2B. X T.
Where:
B. Frequency resolution; bZxz.net
T. -- Effective averaging time;
Na-- should be no less than 120 (see Table B.2 and Figure 6). 4.3.6 Frequency resolution
The frequency resolution necessary to minimize the error between the true value and the indicated value of the velocity spectral density shall be within the limits of 4.3.6.1 for method 1 and within the limits calculated in 4.3, 6.2 for method 2. 4.3, 6, 1 Method 1
The maximum value of the frequency resolution shall be selected from Table 1. Table 1
Test frequency range
4.3.6.2 Method 2
Frequency resolution, method 1
Unit: Hertz
Upper limit of frequency resolution
Frequency resolution B. The narrowest -3 dB bandwidth B shall be selected from the resonant frequency response check (see A.2.6 and A.3.1). The rate resolution is calculated by equation (3):
B. = a XB,
where α1, the factor α takes into account the systematic error E and should be taken from Table 2 (see B.2.3.4). Factor and systematic error in the rectangular window function Systematic error E,/dB
Factor a
Note: For other types of window functions, the factor a should be divided by the factor W in Table H.3 (see B.2.3.4). 4.4 Installation
±0, 5
Unless otherwise specified in the relevant specifications, the sample shall be installed in accordance with the provisions of GB/T2423.10-1995, which refers to GB/T2423.43-1995.6
5 Severity level
5.1 General
The test severity level is composed of the following parameters: test frequency range;
acceleration spectrum density value;
-acceleration spectrum density spectrum type;
test duration.
GB/T2423.56-2006/1EC 60068-2-64:1993 The relevant specifications shall specify each parameter value. They are selected from the following parameters: a) from the given values ​​in 5.2~5.5; b) when a clearly different value is obtained from known environmental conditions, the value is purchased; c) obtained from known relevant data (such as GB/T 4796). 5.2 Test frequency range
If option a) in 5.1 is selected, the test frequency range should be selected from Table 3. Table 3 Test frequency range
The cheek rate f and their relationship with the acceleration spectrum density are shown in Figure 2. 5.3 Acceleration spectral density
Unit: Hz
If option a) in 5.1 is selected, the acceleration spectral density between f and Hz (0 dB in Figure 2) shall be selected from the following values ​​(in units of (m/s\)\/Hz):
0.05;0.1:0.5;1.0,5.0;10,0;50,0;100,0.0 shall be expressed in g., g. being 10 m/s. 5.4 Spectral shape of acceleration spectral density
The spectral shape of acceleration spectral density is specified as a flat spectrum (see Figure 2). In special cases, it may be necessary to specify an acceleration spectral density spectral shape of approximate shape. In this case, the relevant specifications shall specify the shape of the acceleration spectral density curve as a frequency function. It shall be possible to select from 5.2 and 5.3 Select different spectral density values ​​and corresponding frequency ranges from the given values, i.e., the points. In addition, the relevant specifications shall specify the slope between different spectral density values. 5. 5 Test duration
The duration of each axis shall be selected from the following values, in minutes, with a tolerance of 0--5%: 1.3, 10, 30, 100: 300
6 Pretreatment
If the relevant specifications require pretreatment, the corresponding conditions shall be specified. 7 Initial inspection
The appearance, size and function of the sample shall be inspected in accordance with the requirements of the relevant specifications (see B.7). 7
GB/T 2423.56—2006/IEC 60068-2-64: 19938 Test
8.1 General
The test shall be carried out according to different test procedures using method 1 or method 2 according to the relevant specifications. The procedure is as follows: Method 1:
—If required, perform an initial vibration response check (see 8.2); —Equalize with low-magnitude excitation before testing (see 8.3): —Random vibration test (see 8.4);
—If required, perform a final vibration response check (see 8.6). Method 2:
Initial vibration response check (see 8.2);
—Equalize with low-magnitude excitation before testing (see 8.3): Random vibration test (see 8.4);
—If required, perform a final vibration response check (see 8.6). Unless otherwise specified in the relevant specification, the sample shall be subjected to vibration excitation in each selected test axis in turn. Unless otherwise specified in the relevant specification, the order of tests along these axes is not necessary. The control acceleration spectral density of the reference point is obtained from one test point if single-point control is used and from multiple test points if multi-point control is used. For the latter, the relevant specification should state that it is the average of the signals at the various test points that should be controlled within the specified range, and it is the signal value at the selected point, such as the maximum amplitude, that should be controlled within the specified range. In any case of multiple point control, this point becomes the reference point for simulation. When a sample with a vibration damper is to be tested without a vibration damper: special treatment should be given (see B.4). 8.2 Vibration response check
When the relevant specification specifies the use of method 1, it is not required to check the vibration response as part of the test method. However, the relevant specification may also specify that a vibration response check be carried out before or before and after the random vibration test (see 4.2 and Appendix A). When the relevant specification specifies the use of method 2, the vibration characteristics of the sample should be analyzed within the test frequency range. The vibration response check can be carried out according to the sinusoidal or random excitation specified in the relevant specification. The specification should specify the response measurement points on the sample (see 4.2 and Appendix A). When sinusoidal excitation is used, the relevant specification shall specify that at least one sweep cycle covering the test frequency range shall be carried out and that the acceleration amplitude shall be ≤ 10 m/s° or the displacement shall be 5 m, whichever is the smaller. If more accurate response characteristics are to be obtained, the amplitude and sweep rate may be different from the specified values. Long durations should be avoided. To prevent the specimen from being stressed more than in the random vibration test, the vibration amplitude may also be reduced. When the specimen is very sensitive to sinusoidal vibration, the root mean square value of the acceleration when random excitation is used shall not exceed 5% of the energy specified in the random vibration test. The duration shall be as short as possible, but at least long enough to ensure that the free contact is at least N2-120 (see B, 2, 3, 3 and Figure 8). 8.3 Equalization of low-magnitude excitation before testing
Before carrying out random vibration tests at the specified values, it may be necessary to carry out low-magnitude random tests on actual specimens for equalization and preliminary analysis. It is important that the spectral density of the applied acceleration is kept to a minimum during this stage. The permissible duration of random excitation is as follows: g. Root mean square value is lower than -12dB: no time limit: g. Root mean square value is between 12dB and -6dB: not more than 1.5 times of the specified test time:, Root mean square value is between -6dB0dB: not more than 10% of the specified test time. The specified time of random vibration test does not include the duration of the balance. 8.4 Random vibration test
The relevant specifications should select the appropriate test frequency range (f1, to f2.), acceleration spectrum density, acceleration spectrum density spectrum type and test time. If required by the relevant specifications, in order to verify the stability of the random input wave, multiple measurements such as velocity spectrum density and acceleration root mean square value should be carried out at appropriate time intervals at the test point, which should be recorded in the test report.
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