GB/T 2423.5-1995 Environmental testing for electric and electronic products Part 2: Test method Test Ea and guidance: Shock
Some standard content:
GB/T2423.5—1995
This standard is equivalent to the International Electrotechnical Commission standard IEC68-2-27 Environmental testing Part 2: Test method Test Ea and guidance: Shock" 1987 3rd edition.
This standard replaces GB2423.5-81 "Basic environmental testing procedures for electric and electronic products Test Ea: Shock test method" and GB2424.3-81 "Basic environmental testing procedures for electric and electronic products: Shock test guidance". GB2423.5-81 and GB2424.3--81 were drafted with reference to the IEC68-2-27\Basic Environmental Test Procedures Part 2: Various Tests Test Ea: Shock" 1972 2nd Edition, and the IEC standard was divided into two standards, the main text became GB2423.5 shock test method, and the appendix became GB2424.3 shock test guide. This revision merged the test method and guide together, and like the IEC68-2-27 3rd Edition, added Chapter 3 Definitions, and the number of appendices increased from ~ to three, namely Appendix A Guidelines; Appendix B Shock Response Spectrum and Other Characteristics of Pulse Waveforms; Appendix C Comparison of Impact Test Methods. The tolerance requirements for pulse waveforms have been relaxed.||t t||This standard was first issued in 1981 and revised for the first time in August 1995. It came into force on August 1, 1996. From the date of implementation of this standard, the former national standards of the People's Republic of China GB2423.5-81 and GB2424.3-81 shall be repealed at the same time. Appendix A, Appendix B and Appendix C of this standard are all appendices to the standard. This standard was proposed by the Ministry of Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Environmental Conditions and Environmental Testing for Electrical and Electronic Products. The main drafting unit of this standard: the Fifth Institute of the Ministry of Electronics Industry. The main drafters of this standard: Xu Yongmei and Wang Shurong. 34
GB/T2423.5-1995
IEC former
1) All national committees that are particularly concerned about this issue shall participate in the drafting of the standard 1) The formal resolutions or agreements on technical issues formulated by the technical committees of the International Electrotechnical Commission, which reflect and express the international consensus on the issue as much as possible. 2) These resolutions or agreements are for international use in the form of recommended standards and are accepted by national committees in this sense. 3) In order to promote international unification, the International Electrotechnical Commission hopes that all member countries will adopt the contents of the International Electrotechnical Commission's recommended standards as their national standards when formulating national standards, as long as national specific conditions permit. Any differences between the International Electrotechnical Commission's recommended standards and national standards should be clearly stated in the national standards as much as possible. This standard was developed by the International Electrotechnical Commission Technical Committee 50 (Environmental Testing) Subcommittee 50A (Shock and Vibration Testing) .
This third edition of IEC68-2-27 replaces the second edition of 1972, including Amendment 1 of 1982 and Amendment 2 of 1983. The text of this standard is based on the following documents: June Method
50A (Central Office) 161
50A (Central Office) 162
For further information, see the relevant voting reports in the table above. Voting Report
50A (Central Office) 168
50A (Central Office) 169
1 Purpose
National Standard of the People's Republic of China
Environmental testing for electric and electronic products
Part 2: Test methods
Test Ea and guidance: Shock
Environmental testing for electric and electronic products Part 2: Test methods
Test Ea and guidance, Shock
Provides a standard method for determining the ability of a sample to withstand a specified level of severe shock. 2 General description
GB/T 2423. 5—1995
idt IEC 68-2-27:1987
Metabolism C
This standard is written based on specified pulse waveforms. The guidance for selecting and using these pulse waveforms is shown in Appendix A. The characteristics of various pulse waveforms are discussed in Appendix B. This standard includes three pulse waveforms, namely half-sine pulses, post-peak sawtooth pulses and trapezoidal pulses. The choice of pulse waveform depends on many factors, and making such a choice is a difficult task in itself, so this standard does not give a priority order of waveforms (Chapter A3).
The purpose of this test is to reveal mechanical weaknesses and (or) performance degradation, and use this information, combined with relevant specifications, to decide whether the sample is acceptable. In some cases, this impact test can also be used to determine the structural integrity of the sample, or as a means of quality control (Chapter A2).
This test is mainly for non-packaged samples, and samples whose packaging can be regarded as part of the product itself under transportation conditions. The impact of this standard is not intended to simulate the actual impact. If possible, the test severity and impact pulse waveform applied to the sample should simulate the effects of the actual transportation and working environment to which the sample will be subjected. Alternatively, if the purpose of the test is to evaluate the structural integrity, the design requirements should be met (Chapters A2 and A4). During the conditional test, the sample should be fastened directly to the table or fastened to the table by a clamp. For ease of use, the main body of this standard lists the item numbers of Appendix A to be referred to, and Appendix A also lists the item numbers of the main body.
This standard should be used in conjunction with GB2421-89 "General Principles of Basic Environmental Testing Procedures for Electrical and Electronic Products". 3 Definitions
The terms used in this standard are generally based on the provisions of GB/T2298--91 "Terms for Mechanical Vibration and Shock" or GB2421-89. For the purpose of this standard, the following additional terms and definitions shall be used. 3.1 Fixing point
The part where the sample is connected to the fixture or the sample is connected to the impact test machine table. It is usually used to fix the sample during use. 3.2 Check point
The check point refers to the fixing point closest to the center of the impact test machine table, except when a fixing point with better rigidity to the impact table is used as the check point. The State Administration of Technical Supervision approved it on August 29, 1995.
It was implemented on August 1, 1996.
GB/T2423.5---1995
Note: This definition is only applicable to the case where there is only one designated check point. The check point defined in other standards of GB 2423 is used for control tests through more than one designated check point. 3.3 Shock test severity The shock test severity is the combination of peak acceleration and nominal pulse duration. 3.4 Velocity change Velocity change is the absolute value of the sudden change in velocity produced by the application of the specified acceleration. NOTE A change in velocity is generally considered to be sudden if it occurs in a time shorter than the fundamental period of the excitation pulse involved. 3.5 Standard acceleration due to the earth's gravity (g,) Standard acceleration due to the earth's gravity (g,) which varies with altitude and geographical location. For the purposes of this standard, the value is taken as an integer of 10 m/s.
4 Test equipment description
4.1 Characteristics requirements
When the shock test machine and fixture are equipped with the sample, the shock pulse applied at the test point shall be approximately one of the nominal curves of acceleration versus time shown as the dotted line in Figures 1, 2 and 3. 4.1.1 Basic pulse waveform
The true value of the actual pulse shall be within the tolerance limit indicated by the solid line in the relevant figure. Note: When a pulse waveform that falls within the specified tolerance range cannot be obtained, the relevant specification shall specify another applicable method (Chapter A5). All specified pulse waveforms are as follows. The order in which they are arranged does not indicate priority for the preceding pulses. Rear peak sawtooth pulse: an asymmetrical triangle with a short fall time, as shown in Figure 1. Half-sine pulse: half a cycle of a sine wave, as shown in Figure 2. Trapezoidal pulse: a symmetrical quadrilateral with short rise and fall times, as shown in Figure 3. 4.1.2 Speed change tolerance
For all pulse waveforms, the actual speed change shall be within ±15% of its corresponding nominal pulse value. When the speed change is determined by the integration of the actual pulse, it should be integrated from 0.4D before the pulse to 0.1D after the pulse, where,D is the duration of the nominal pulse.
Note: If the velocity variation tolerance cannot be obtained due to the lack of an accurate integrating device, the relevant specification shall specify an alternative method. 4.1.3 Lateral motion
The positive or negative peak acceleration perpendicular to the predetermined impact direction at the test point shall not exceed 30% of the nominal pulse peak acceleration in the predetermined direction. And its measurement system shall comply with the provisions of 4.2 (Chapter A5). Note: If the error requirements for lateral motion cannot be met, the relevant specification shall specify an alternative method (Chapter A5). 4.2 Measurement system
The frequency characteristics of the measurement system shall ensure that the true value of the actual pulse measured in the predetermined direction of the test point is within the tolerance range required by the figure referenced in 4.1.1.
The frequency characteristics of the entire measurement system, including the accelerometer, have a significant impact on the measurement accuracy and should be within the tolerance limits shown in Figure 4 (Chapter A5).
4.3 Installation
During the conditional test, the sample shall be installed on the table or fixture of the impact test machine according to its normal installation method. The installation method shall comply with the provisions of GB/T2423.43-1995 "Environmental testing for electrical and electronic products Part 2: Test methods Requirements and guidelines for installation of components, equipment and other products in dynamic tests such as impact (Ea), collision (Eb), vibration (Fc and Fd) and steady-state acceleration (Ga)". 5 Test severity level
The relevant specifications shall give both the pulse waveform and the test severity level. A pulse waveform given in 4.1.1 and a severity level specified in Table 1 shall be selected.
GB/T2423.5--1995
Unless otherwise specified, a set of data on the same line in Table 1 shall be selected. The data in the rows marked with * shall be used first. The corresponding speed changes specified are listed in Table 1 (see Chapter A4). Note: If the severity level in Table 1 cannot simulate the impact of a known environment on the sample, the relevant specification may select one of the three standard pulse waveforms shown in Figures 1, 2 and 3 (see Chapter A4) to specify other appropriate test severity levels. Table 1 Acceleration and duration of pulses
Acceleration
￥15000
Pretreatment
Corresponding nominal
Pulse duration
The relevant specification may propose pretreatment requirements. 7 Initial test
Half sine
2ADX10-3
The sample should be tested for appearance, size and function in accordance with the provisions of the relevant specifications. 8 Conditional test
8.1 Application of impact
Corresponding velocity change
Rear peak sawtooth
Au=0.5ADX10-3
Au= 0.9ADX10-3
Unless otherwise specified in the relevant specification, three impacts shall be applied continuously in each of the three mutually perpendicular directions of the sample, i.e. 18 times in total. When multiple identical samples are tested simultaneously, they may be installed in different directions so that the samples can be subjected to impacts in the above-mentioned axes and directions at the same time (see Chapter A7).
8.2 Working mode and function monitoring
The relevant specification shall specify
a) whether the sample is to work and whether its function is to be monitored during the impact test; and/or b) whether the sample is to withstand the impact applied. For the above two situations, the relevant specification shall give the criteria for acceptance or rejection. 38
9 Recovery
The relevant specification may put forward recovery requirements.
10 Final inspection
GB/T 2423.5—1995
The samples shall be inspected for appearance, dimensions and functions in accordance with the relevant specifications. The relevant specifications shall provide the criteria for acceptance or rejection. 11 Contents to be provided in the relevant specifications
When the relevant specifications adopt this test, the following contents shall be provided: a) Pulse waveform (A3) (4.1.1),
b) Tolerance under special circumstances (A5) (4.1.1); c) Speed change under special circumstances (A6) (4.1.2); d) Lateral movement under special circumstances (4.1.3); e) Installation method (4.3)
f) Severity level (A4)||t t||(Chapter 5);
g) Pretreatment (Chapter 6);
h) Initial test (Chapter 7);
i) Direction and number of impacts only in special cases (A7);j) Operating mode and function monitoring (8.2), k) Acceptance and rejection criteria (8.2, Chapter 10);1) Recovery (Chapter 9);
m) Final test (Chapter 10);
n) High cut-off frequency (A5)
(Figure 4).
GB/T2423.5—1995
Integration time
2. 4D= T,
-Nominal pulse line
-Tolerance range line
D Duration of nominal pulse
A Peak acceleration of nominal pulse
T, When the impact is generated by a conventional impact tester, the shortest time for monitoring the pulse is T, When the impact is generated by an electric vibration table, the shortest time for monitoring the pulse is Figure 1 Post-peak sawtooth pulse
Integration time
----Nominal pulse line
Tolerance range line
D Duration of nominal pulse
A Peak acceleration of nominal pulse
T1 When the impact is generated by a conventional impact machine, the shortest time for monitoring the pulse is T When the impact is generated by an electric vibration table, the shortest time for monitoring the pulse is Figure 2 Half-sine pulse
GB/T2423.5—1995
Integration time
--*Nominal pulse line
Tolerance range line
D Duration of nominal pulse
A Peak acceleration of nominal pulse
The shortest time for monitoring pulse when impact is generated by conventional impact machine T
The shortest time for monitoring pulse when impact is generated by electric vibration table Figure 3 Trapezoidal pulse
Pulse duration
18 and 30
GB/T2423.51995
Low load stop frequency
High cut-off lock rate
24aB/oct
Should exceed + when
Note: For impacts with duration equal to or less than 0.5ms, the,, and f. given by this institute may be too high. In this case, the relevant specifications may specify other applicable values.
Frequency characteristics of the measurement system
A1 Introduction
GB/T2423.5—1995
Appendix A
(Appendix to the standard)
Guidelines
This test provides a method to reproduce the actual environmental effects in the test room. The effects produced on the sample by this method can be compared with the environmental effects that the sample may actually experience during transportation or operation. The basic purpose of this test is not to simulate the real environment.
In order to obtain consistent test results when tested by different people in different test rooms, the parameters specified in this test are standardized and have appropriate tolerances. The standardization of values also enables components to be classified according to their ability to withstand a certain test severity level specified in this standard.
For ease of use, this appendix lists the relevant items in the text of the standard. A2 Scope of application of impact test
Many samples are susceptible to impact during use, loading and unloading, and transportation. The magnitude of these impacts varies greatly and has complex properties. This test provides a very convenient method for determining the ability of samples to withstand these non-repetitive shock conditions. For repetitive shocks, GB/T2423.6-1995 "Environmental testing for electrical and electronic products Part 2: Test method Test Eb and guidance: Collision" is more appropriate (Appendix C).
Shock tests are also applicable to structural integrity tests on component-type samples for identification or quality management. In these cases, high acceleration shocks are usually used, and the main purpose is to apply a known impact force to the internal structure of the sample (especially for samples with cavities) (Chapter 2).
Any specification writer who intends to use this standard should refer to Chapter 11 "Contents to be given in the relevant specifications" to ensure that the requirements for these contents can be specified.
A3 Pulse waveform (Chapter 2)
This standard specifies three commonly used shock pulse waveforms, any of which can be selected according to the purpose of the test (see also 4.1.1 and Table 1 of this standard).
Half-sine pulses are suitable for simulating the impact effects caused by the impact of linear systems or the deceleration of linear systems, such as the impact of elastic structures.
Trapezoidal pulses can produce higher responses than half-sine pulses over a wider spectrum. If the purpose of the test is to simulate the effects of a shock environment such as that caused by explosive bolts during the launch phase of a space probe or satellite, this shock waveform can be used. Note: The most commonly used is the half-sine pulse, and the trapezoidal pulse is basically not used for component-type samples. The post-peak sawtooth pulse has a more uniform response spectrum compared to the half-sine pulse and the trapezoidal pulse.
The shock spectrum data related to these pulses can be found in Appendix B of this standard. When the shock spectrum of the working or transportation environment is known, Figures B4, B5 and B6 should be referred to in order to select the pulse waveform that is closest to this shock spectrum. When the shock response spectrum of the working or transportation environment is unknown, Table A1 should be referred to, because Table A1 lists the test severity levels and pulse waveforms for samples suitable for various types of transportation and various working methods. For packaged samples, the shocks experienced during handling and transportation are usually simple in characterization, so a half-sine pulse derived from observing the velocity variation can be used. 43
GB/T 2423.5—1995
Table A1 Typical examples of pulse waveforms and test severity levels for various occasions The test severity levels indicated in this table for various situations are not mandatory, but are typical. It must be remembered that there will be situations where the actual severity level is different from the severity level shown in the table
Peak acceleration
Duration
Pulse waveform
Post-peak sawtooth
Half-sine ladder
Post-peak sawtooth
Half-sine ladder
Post-bee sawtooth
Components for transport in reliable packaging by wheeled vehicles
(standard road or railway), subsonic or supersonic transport aircraft, merchant ships, light naval craft.
Mounted in wheeled vehicles (standard road
half-sine ladder or railway), subsonic or supersonic transport
rear peak sawtooth
half-sine ladder
half-sine
*Basically not intended for component type samples. A4 test severity level (Chapter 2 and Chapter 5)
components in equipment transported by aircraft, merchant ships, light ships, or components installed and used on the above-mentioned transport
tools.bZxz.net
Components installed in heavy industrial equipment
Components transported by off-road vehicles in reliable packaging,
components in equipment transported by off-road vehicles, or components installed and used on off-road vehicles.
Mounted in subsonic Components in equipment on high-speed or supersonic transporters. Components in equipment transported in bulk on road or rail vehicles for long distances Structural integrity tests for semiconductors, integrated circuits, microcircuits, and microelectronic assemblies Structural integrity tests for semiconductors, integrated circuits, microcircuits Basic tests of equipment for handling and transportation. Structural strength of equipment permanently installed on the ground or in strong, shock-resistant packaging for transportation by road, rail or air. Installation in a secure position on a standard road or rail or transport aircraft or in a transport aircraft Equipment transported in this way Equipment mounted or transported in a secure position on an off-road vehicle. Equipment transported in bulk in standard road or rail vehicles for long distances. Products used in industrial areas and subjected to shocks from mechanical handling equipment such as dock cranes, fork-lift trucks, etc., subjected to severe handling shocks during road or rail transport. High-intensity shocks due to detonation, separation of multi-stage rockets (air vehicles), aerodynamic shocks, reentry of space vehicles, etc. Portable equipment Shocks caused by explosions on land, at sea or in the air The test severity and pulse waveform applied to the sample should be as consistent as possible with the environment to which the sample will be subjected during transportation or in the course of operation. If the purpose of the test is to evaluate the structural integrity, it should be subjected to the environment required by the design. 44
GB/T2423.5-1995
Transportation environmental conditions are often more severe than working environmental conditions. In this case, the selection of the test severity level needs to be consistent with the transportation environment. However, although the sample only needs to withstand the transportation environmental conditions, it is usually required to operate in the working environmental conditions. Therefore, if possible, the sample must usually be subjected to impact tests under the above two conditions, that is, impact tests for parameter measurement after the transportation environmental conditions test and impact tests for functional inspection during the working environmental conditions test. When determining the test severity level, an appropriate safety margin may need to be given between the test severity level and the actual environmental conditions. When the actual transportation and working environmental conditions are unknown, the appropriate test severity level should be selected from Table 1, and Chapter B3 should also be referred to. In determining the severity of the test, the specification writer should consider the relevant content of the environmental condition series standards, such as GB4796-84 "Classification of environmental parameters for electrical and electronic products and their severity classification", GB4798.1-86 "Environmental conditions for the application of electrical and electronic products" and GB4798.5-87 "Environmental conditions for the application of electrical and electronic products: ground vehicle use". However, it should be remembered that the above standards list the actual shock values experienced, while this standard can give standard shock pulses for testing consistent with the shock effects during life. A5 Tolerances
The test method specified in this standard has high reproducibility when the tolerance requirements for the basic pulse waveform, velocity variation and lateral movement are met.
However, there are some exceptions to these tolerances, which are mainly for samples with high reaction loads, that is, samples whose mass and dynamic response may affect the characteristics of the shock tester. In these cases, the relevant specification may relax the tolerance range or provide that the actual tolerance obtained be recorded in the test report (see 4.1.1; 4.1.2 and 4.1.3). When testing samples with high reaction loads, impact pre-adjustment must be carried out to check the characteristics of the impact machine after loading. For complex samples, since only one or a limited number of samples may be available for testing, repeated impacts before formal testing may lead to over-testing or unrepresentative cumulative damage. In this case, it is recommended to use a representative sample (such as a non-conforming sample) or, when such a sample is not available, a model with accurate mass and center of gravity position can be used for impact pre-adjustment. However, it should be pointed out that the above model cannot have exactly the same dynamic response as the real sample. The frequency response of the entire measurement system, including the accelerometer, is an important factor in achieving the required pulse shape and severity level, and should be within the tolerance range shown in Figure 4. When a low-pass filter is required to reduce the high-frequency resonance effects inherent in the accelerometer, the amplitude-frequency and phase-frequency characteristics of the measurement system must be considered to avoid waveform distortion caused by the measurement system itself (see 4.2). For shocks with a pulse duration equal to or less than 0.5 ms, the f and f indicated in Figure 4 may appear too high. In this case, the relevant specification may specify them separately (see 4.2). A6 Velocity change (see 4.1.2)
For all pulse waveforms, the actual velocity change is specified. This velocity change can be determined by a number of methods, for example: For shock pulses that do not cause rebound motion, it is determined by the impact velocity. For a free-fall machine, it is determined by the height of the drop and rebound. It is determined by the integration of the acceleration-time curve. When the integration technique is specified, the actual velocity change should be determined from the integral between 0.4D before the pulse and 0.1D after the pulse, where D is the nominal pulse duration, unless otherwise specified. However, it must be pointed out that the determination of the velocity change by electronic integration may be difficult and may require precision equipment. Therefore, the test cost should be considered before using this method. One of the purposes of specifying speed changes and their corresponding tolerance requirements is to facilitate the test laboratory to achieve a shock pulse equivalent to the nominal pulse, that is, in the center of the pulse tolerance range (see Figures 1, 2 and 3). Only in this way can the reproducibility of the test be guaranteed. Another purpose of specifying speed changes is related to the shock response spectrum of the pulse (see Chapter B3). A7 condition test (see 8.1)
One of the basic requirements of this test is to apply three impacts in each of the six directions of the sample. When it is not necessary to test all six directions, for example due to symmetry reasons or because there are directions where the impact effect is significantly smaller, the relevant specifications can reduce the number of test directions to 45
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