GB/T 2423.15-1995 Environmental testing for electric and electronic products Part 2: Test method Test Ga and guidance: Steady-state acceleration
Some standard content:
GB/T2423.15-1995
This standard is revised based on the second edition of 1983 and the first revised edition of 1986 of the International Electrotechnical Commission IEC68-2-7 "Environmental testing Part 2 Test methods Test Ga and guidance: Steady-state
acceleration". And it is adopted as such. This standard replaces GB2423.15--81 "Basic environmental test procedures for electric and electronic products Test Ga: Constant acceleration test method" and GB2424.8-81 "Basic environmental test procedures for electric and electronic products Constant acceleration test guide". GB2423.15-81 and GB2424.8-81 were drafted with reference to the first edition of IEC68-2-7 in 1968. And this version of IEC68-27 standard is divided into two standards. The main body (test method) becomes GB2423.15; the appendix (guide) becomes GB2424.8. This revision merges the two parts together. According to the second edition of IEC68-2-7 (1983), Appendix B "Supplementary Guidelines" was added; according to the first revision in 1986, the severity levels and Table B1 of Chapter 4 were deleted and revised. The title of GB2423.15-81 was translated as "Constant Acceleration Test Method", and this revision was changed to "Steady State Acceleration" (Acceleration, steady state). The purpose is to make the expression more accurate and more in line with the actual situation. This standard was first issued in 1981 and revised for the first time in August 1995. It will be implemented on August 1, 1996. From the date of implementation of this standard, the original national standards of the People's Republic of China GB2423.15-81 and GB2424.8--81 will be abolished at the same time. Appendix A of this standard is the standard appendix;
Appendix B of this standard is the indicative appendix.
This standard is 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 Environmental Conditions and Environmental Testing of Electrical and Electronic Products. The drafting units of this standard are: Shanghai Electronic Instrument Standard and Measurement Test Institute, China Aviation Industry Corporation No. 511 Factory and the Fifth Research Institute of the Ministry of Electronics Industry.
The main drafters of this standard are: Lu Zhaoming, Lin Zongyang and Wang Shurong. 190
GB/T2423.15—1995
IEC Before
This standard was formulated by the International Electrotechnical Commission Technical Committee 50 (Environmental Testing) and the 50A Technical Committee (Shock and Vibration Testing).
This standard IEC68-2-7 (1983) second edition combines the first edition (1968) and the first revision (1982). Many editorial changes have been made to adapt to the changes to the installation in IEC68-2-47 "Environmental Testing Part 2: Test Methods Requirements and Guidelines for Installation of Components, Equipment and Other Products in Dynamic Tests such as Shock (Ea), Bump (Eb), Vibration (Fc and Fd) and Steady Acceleration (Ga)". The first draft of the test Ga was discussed at the Aix-les-Bains Conference in 1964, the Tokyo Conference in 1965, and the London Conference in 1966, and the draft was formed into Document 50A (Office of the Central Committee). It was submitted to the technical committees of various countries for voting according to the June rule in March 1967. The technical committees of the following countries voted publicly in favor of the first version of this standard: Australia
Belgium
Israel
Canada
Turkey
Czechoslovakia
South Africa (Republic)
United Kingdom
A draft of Appendix B (Supplementary Guidelines) was discussed at the Moscow Conference in 1977, and the conference formed the draft into Document 50A (Office of the Central Committee) No. 151. It was submitted to the technical committees of various countries for voting according to the "June Rule" in February 1980. The technical committees of the following countries are open for voting: Australia
Turkey
Belgiumwww.bzxz.net
Hungary
Israel
Romania
United Kingdom
Other IEC standards referenced in this standard:
Canada
North Korea (Democratic Republic of)
South Africa (Republic of)
IEC68-1 Basic environmental testing procedures Part 1: General principles and guidelines Egypt
Spain
New Zealand
IEC68~2-47 Environmental testing Part 2: Test methods Installation requirements and guidelines for components, equipment and other products in dynamic tests such as impact (Ea), collision (Eb), vibration (Fc and Fd) and steady-state acceleration (Ga) IEC721 Classification of environmental conditions
The second edition of this standard was revised for the first time in June 1986 by Sub-Technical Committee 50A. Main contents of the revision:
I. 4. Severity level (delete equivalent gn value); Table B1: Examples of typical test levels for different purposes (except equivalent g value and application examples, individual data have been adjusted). 191
1 Purpose
National Standard of the People's Republic of China
Environmental testing for electric and electronic products
Part 2: Test methods
Test Ga and guidance, Acceleration, steady stateGB/T 2423.15—1995
idt IEC 68-2-7: 1986
Replaces GB2423.15-81
GB2424.8—81
Used to determine whether the adaptability and performance of the structure of components, equipment and other electrical and electronic products (hereinafter referred to as "samples") are good under the force (excluding gravity) generated by the steady-state acceleration environment, such as the force generated by running vehicles, air vehicles, rotating machinery and projectiles, and to assess the structural integrity of some components. 2 General description
Samples installed in moving bodies will be subjected to the forces generated by steady-state acceleration. Although in some cases, the acceleration of ground transportation vehicles is also quite large. However, this environment is most obvious in air vehicles and rotating machinery. Generally speaking, the acceleration values experienced by the sample during use are different along each main axis of the moving body. In addition, the acceleration values in the two opposite directions of each main axis are often different. If the orientation of the sample is not certain relative to the moving body, the relevant specification should specify the steady-state acceleration levels in two opposite directions of each main axis of the sample after taking into account the maximum acceleration values of the moving body on different axes. 3 Test conditions
3.1 Description of the test equipment
3.1.1 Overview
When a centrifuge is used to produce steady-state acceleration, the direction of acceleration is toward the center of the rotating system. In some special cases, because some samples may be sensitive to gyroscopic couples, only a machine that can produce linear acceleration can be used for this test, and the relevant specifications should explain this.
3.1.2 Tangential acceleration
When the speed of the centrifuge increases from zero to the specified value, or decreases from the specified value to zero, the control of the centrifuge should ensure that the tangential acceleration experienced by the sample is not greater than 10% of the specified steady-state acceleration value. 3.1.3 Acceleration gradient
The size of the centrifuge relative to the sample should be such that no part of the sample (except the hanging leads) will be subjected to a steady-state acceleration value with a tolerance exceeding the value specified in 3.1.4.
3.1.4 Acceleration tolerance
If the linear dimension of the sample is less than 10 cm, any part of the sample (except the hanging leads) shall be within ±10% of the specified steady-state acceleration value.
Approved by the State Administration of Technical Supervision on August 29, 1995
Implementation on August 1, 1996
GB/T2423.15-1995
In other cases, the specified steady-state acceleration tolerance is -10% to +30%. 3.2 Installation
It shall be in accordance with 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)" stipulates that the sample is installed on the test equipment.
Note: For safety reasons, the sample should be prevented from being thrown out when the mounting accessories are damaged. Moreover, any safety device used should not introduce additional stress during the test. 4 Severity level
The relevant specifications should specify the acceleration value of the test, which should be selected from the following standard values when possible. If necessary, the angle of the applied acceleration relative to the axis of the sample should be specified.
Note: When specifying the acceleration value, the purpose of the test should be considered, whether it is to check the structural integrity of the sample or to assess the ability of the sample to withstand the forces generated by the vehicle or rotating machinery.
The standard levels of the test are:
10 000
100000
200000
300000
500000
Note: If the author of the relevant specification still wants to give the acceleration in the form of "g.", when selecting the acceleration value in this standard, "g." should be rounded to the nearest integer, that is, 10 m/s.
5 Initial inspection
The sample shall be inspected for appearance, dimensions and function in accordance with the provisions of the relevant specifications. 6 Conditional test
Test procedure using a centrifuge
6.1 Unless otherwise specified in the relevant specifications, the three mutually perpendicular axes of the sample shall be tested in two opposite directions in sequence. 6.2 The centrifuge shall be able to generate the speed required for the specified acceleration value. 6.3 After the required speed is reached, it shall be maintained for not less than 10s or for the time specified in the relevant specifications. 6.4 The relevant specifications shall specify the following functional conditions that must be met or the acceleration levels to be experienced at the corresponding acceleration levels (Chapter A2). a) Sample a) The sample does not have to work within the performance limits specified in the relevant specifications, but no permanent disorder shall occur; c) The sample does not need to work, but no permanent disorder shall occur; d) Although the sample may have permanent damage or disorder, it shall not be loose. 6.5 The relevant specifications shall specify the inspection sequence of the inspection items specified in Article 6.4 (Chapter A2). 193
Final inspection
GB/T2423.15—1995
The appearance, size and function of the sample shall be inspected in accordance with the provisions of the relevant specifications. Contents that the relevant specifications should provide
The relevant specifications adopt this test When specifying the method, the following details shall be specified: type of test equipment (3.1);
method of sample installation (3.2);
acceleration level (Chapter A2 and Chapter B2) (Chapter 4); axis and direction of acceleration (Chapter A1) (Chapters 4 and 7); initial test (Chapter 5);
duration of test (6.3);
function of the sample during the test and the conditions it withstands (Chapter B1) (6.4); inspection sequence (6.5);
final test (Chapter 7).
direction of test for A1 sample
GB/T2423.15-1995
|Appendix A
(Standard Appendix)
In many cases, especially in aviation, the force generated by the acceleration of a moving body is always complex. However, it can always be regarded as a simple force at any moment. This force can be expressed by the angle direction of the three main axes of the moving body. For design purposes, the maximum acceleration value of a specific motion of the moving body can be decomposed and specified relative to each main axis of the moving body. If the sample has a known fixed orientation relative to the given moving body and the three components of acceleration must be simulated simultaneously, these components can be combined and the sample is subjected to only a single acceleration value equal to the sum of the three components in amplitude and direction. However, this requires a very complex fixture to enable the sample to have such an orientation relative to the testing machine that a steady-state acceleration is applied along the direction of the sum. Unless it is very important to maintain the angular relationship between the total sum acceleration and the sample, it can be simplified to apply the sum acceleration value along the main axis containing the highest component of the three specified component values, and the remaining axes are applied with appropriate acceleration values. When the orientation of the test sample to the moving body is unknown, the maximum sum acceleration should be applied in two opposite directions along each of the three main axes of the sample.
A2 Acceleration severity level
Some of the acceleration severity levels listed in Chapter 4 of this standard represent actual environments, while others (especially high levels) are artificial environments used to test the structural integrity of certain electronic components. Due to the high acceleration values that may be generated in rotating machinery, the actual acceleration levels specified for some purposes may overlap with the artificial levels specified for other purposes. The design and finalization of aviation equipment requires that functional and tolerance tests be carried out in sequence at different acceleration levels. There is a certain factor associated between the functional and tolerance requirements. The requirements of these tests should be specified in the design requirements of aviation equipment, and generally the following four points need to be met:
a) Acceptance or working level: Generally speaking, the sample is required to work at this level, and the performance is not less than the specified limit; b) Higher supplementary level: The sample can be required to work, but the performance is not necessarily within the specified limit; c) Structural or extreme level: A higher acceleration level that checks the sample's resistance to structural deformation; d) Other levels: This level uses steady-state acceleration tests as a means to check the firmness of the installation connection of the test sample. And it will not break loose in an emergency, so as to avoid personal accidents directly or due to crosstalk at the spare lead-out terminals. The relevant specifications should specify the conditions that should be met among the above conditions, the acceleration levels that should be used, and the working conditions that must be met (see 6.4.6.5).
In some application examples, the compiler of the relevant specifications cannot always specify the various levels that comply with the above a) to d), but only one level. It is specified based on the maximum acceleration measured and calculated for the moving body, as well as the safety factor agreed by both parties. When specifying this test, the relevant specifications should specify the required performance category (see 6.4; 6.5). When selecting the acceleration level, the relevant specifications should take into account that even in a known direction, the maximum acceleration values at different locations of the moving body may vary greatly.
Some components, especially semiconductor devices, should use very high acceleration to check the integrity of the structure (robust mechanical assembly). Although this level has nothing to do with the actual use conditions, it can be used as a simple means of applying high stress to the sample to expose possible structural weaknesses.
When using a centrifuge to test a sample with a rotating component (such as a gyroscope), the coupling effect between the rotation of the component and the rotation of the centrifuge may make the test difficult. In this case, the relevant specifications should propose appropriate test methods and specify the corresponding working conditions of the sample during the test and the acceptable changes in performance tolerances. 195
B1 Test Purpose
CB/T 2423.15—1995
Appendix B
(Indicative Appendix)
Supplementary Guidelines
The purpose of the steady-state acceleration test is to simulate the effects of steady-state acceleration on the sample installed on a rotating component, projectile and running vehicle, especially space vehicles.
In terms of structural integrity, this test can also be used as a method to determine the quality of component design and production. The relevant specifications should clearly specify whether the sample must work when undergoing the test, or whether it is only required that its structure can withstand the effects of steady-state acceleration and work normally after the test. In either case, the specification shall specify the acceptable performance tolerances and permissible perturbations required to determine whether the sample is qualified in accordance with the requirements of 6.4. B2 Selection of test severity levels (Chapter 4, Chapter 6, Chapter 8 c) and f)) Refer to the severity levels in Chapter A2.
The specification writer who adopts this test method should refer to Chapter 8 and include all necessary information in the relevant specification. Whenever possible, the severity level applied to the test sample should be related to the expected conditions to which the test sample will be subjected during transportation or operation. If this information is available, the appropriate severity level should be selected from the values given in Chapter 4. When the severity level is not applicable, the relevant specification may select the most appropriate severity level from the typical severity levels for different uses listed in Table B1.
Note: The various parts of IFC721: Classification of Environmental Conditions are related to actual steady-state accelerations. The purpose of this standard is to make the values of the standardized tests produce the same effects as the actual environment. Table B1 Examples of typical test levels for different purposes plus
B3 Tolerance requirements (see 3.1.2, 3.1.4) Speed
1001000
a≥5 000
This test method has high reproducibility when the linear dimension of the sample is small, for example less than 10 cm. For larger samples, the reproducibility is lower. This depends on the relative size of the sample and the centrifuge. 196
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.