GB/T 2423 Environmental testing - Part 2: Test methods is divided into several parts according to test methods.
This part is Part 63 of GB/T 2423.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part was proposed by and is under the jurisdiction of SAC/TC 8 Technical Committee on Environmental Conditions for Electric and Electronic Products and Environment Test of Standardization Administration of China.
Environmental testing - Part 2: Test methods - Test: combined temperature (cold and heat)/low air pressure/vibration (mixed mode)
1 Scope
This part of GB/T 2423 specifies the basic requirements, severity, test procedures and other technical rules for the combined test of temperature (cold and heat)/low air pressure/vibration (mixed mode).
This part is applicable to determining the adaptability of products to storage, transportation and use under the combined conditions including temperature (cold and heat), low air pressure and vibration (mixed mode). For a combined test with the change of temperature, please refer to this part.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2422 Environmental testing - Guide to drafting of test methods - Terms and definitions
GB/T 2423.1 Environmental testing for electric and electronic products - Part 2: Test methods- Tests A: Cold
GB/T 2423.2 Environmental testing for electric and electronic products - Part 2: Test methods - Test B: Dry heat
GB/T 2423.10 Environmental testing for electric and electronic products - Part 2: Tests methods - Test Fc: Vibration (sinusoidal)
GB/T 2423.21 Environmental testing for electric and electronic products - Part 2: Test methods - Test M: Low air pressure
GB/T 2423.22 Environmental testing - Part 2: Tests methods - Test N: Change of temperature
GB/T 2423.26 Environmental testing for electric and electronic products - Part 2: Tests methods - Test Z/BM: Combined dry heat/low air pressure tests
GB/T 2423.43 Environmental testing for electric and electronic products - Part 2: Test methods - Mounting of specimens for vibration, impact and similar dynamic tests
GB/T 2423.56 Environmental testing for electric and electronic products - Part 2: Test methods - Test Fh: Vibration, broadband random and guidance
GB/T 2423.58 Environmental testing for electric and electronic products - Part 2: Tests methods - Test Fi: Vibration - Mixed mode
GB/T 2424.26 Environmental testing for electric and electronic products - Part 3: Supporting documentation and guidance - Selecting amongst vibration tests
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2422, GB/T 2423.1, GB/T 2423.2, GB/T 2423.10, GB/T 2423.21, GB/T 2423.22, GB/T 2423.26, GB/T 2423.43, GB/T 2423.58 and GB/T 2424.26 apply.
4 General description
This is a combined test consisting of Test A: cold, Test B: heat, Test M: low air pressure, Test N: change of temperature and Test Fi: vibration (mixed mode).
The test samples shall, at the laboratory temperature, be subjected to a vibration test, a temperature test and a combined test and temperature/low air pressure in sequence according to the test procedure. Finally, the test samples shall be subjected to a combined test of temperature (cold and heat)/low air pressure/vibration (mixed mode) by superimposing the vibration (of a mixed mode). When the test samples have passed a single vibration (of a mixed mode) test, a temperature test and a combined test of temperature/low air pressure, they can directly be subjected to the combined test of temperature (cold and heat)/low air pressure/vibration (mixed mode).
Whether a test sample shall be in working condition during the tests shall be determined by relevant specifications.
Annex A gives the guide rules of the tests.
5 Test equipment
The test equipment shall meet the requirements of CB/T 2423.1, GB/T 2423.2, GB/T 2423.10, GB/T 2423.21, GB/T 2423.22, GB/T 2423.26, GB/T 2423.56, GB/T 2423.58 and GB/T 2424.26 for test equipment. A.4 gives relevant information of the test equipment.
6 Installation of test samples
The installation of test samples shall simulate the actual installation and meet the installation requirements of GB/T 2423.1, GB/T 2423.2, GB/T 2423.43 and GB/T 2423.58. For the tests on heat-dissipating samples, the insulated pad between a test sample and the vibration table shall be of high rigidity and low thermal conductivity (of thermal insulation).
7 Severities
7.1 General
The severities of the tests are jointly determined by those of temperature, air pressure and vibration.
For some relevant specifications, severities of temperature, air pressure and vibration selected from 7.2~7.5 may be prioritized for a test grade combination.
7.2 Temperature severities
See Table 1 for temperature severities.
Table 1 Temperature severities
Cold/℃ +5 -5 -10 -25 -40 -55 -65
Tolerance/K ±3
Heat/℃ +155 +125 +100 +85 +70 +55 +40 +30
Tolerance/K ±2
Note 1: In cold, when the air pressure is lower than 10kPa and thus it is difficult to reach the specified temperature tolerance, some relevant specifications may specify the tolerance separately.
Note 2: In heat, if the volume of the test chamber (room) is large and it is impossible to maintain a deviation of ±2K, it can be extended to ±3K at a temperature of 100℃ and below; to ±5K at a temperature of 100℃~200℃ (excluding 100℃), which shall be recorded in the report.
7.3 Air pressure severities
See Table 2 for air pressure severities.
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Table 2 Air pressure severities
7.4 Vibration severities
7.4.1 Parameter setting
7.4.1.1 The severity of the mixed-mode vibration test is determined by the combination of the following parameters:
a) Test frequency range;
b) Broadband acceleration spectral density;
c) Shape of the acceleration spectral density curve;
d) Narrowband randomization;
e) Sinusoidal component;
f) Sweep frequency speed;
g) Test duration.
7.4.1.2 The relevant specifications shall specify that each parameter shall:
a) Be selected from the values given in 7.4.2~7.4.4, or
b) Be obtained from the known environment if obviously different values are given.
Note: If the random and sinusoidal magnitude is determined by actual measured data, special attention should be paid that the adopted data processing technique may seriously affect the amplitude of different signals. See GB/T 2424.26.
7.4.2 Broadband random vibration
7.4.2.1 Test frequency range
The frequency limits selected for the test frequency range selected in the relevant specifications shall be as follows as far as possible: …1, 2, 5, 10, 20, 50…, with the lower limit frequency f1 starting at 1Hz as a minimum and the upper limit frequency f2 reaching up to 5,000Hz as a maximum.
7.4.2.2 Acceleration spectral density for broadband random vibration
The following data are expressed in(m/s2)2/Hz or m2/s3, and the acceleration spectral density values between f1 and f2 given in relevant specifications (see Figure 1), shall be as follows as possible: …1, 2, 5, 10…, with 0.01 as the minimum and 100 as the maximum.
7.4.2.3 Shape of the acceleration spectral density curve
The acceleration spectral density curve specified in this test has a straight section, as shown in Figure 1. Under special circumstances, a curvilinear acceleration spectral density curve can be specified, and the relevant specifications shall specify the shape of the curve according to forms of frequency functions. Different magnitudes and their corresponding frequency ranges, i.e. discontinuity points, shall be selected from the values given in 7.4.2.1 and 7.4.2.2 as far as possible. In addition, the relevant specifications shall specify the gradient of magnitudes.
Foreword II
1 Scope
2 Normative references
3 Terms and definitions
4 General description
5 Test equipment
6 Installation of test samples
7 Severities
7.1 General
7.2 Temperature severities
7.3 Air pressure severities
7.4 Vibration severities
7.5 Duration of the combined test of temperature (heat and cold)/low air pressure/vibration (mixed mode)
8 Preconditioning
9 Initial inspection
10 Tests
10.1 Test preparations
10.2 Condition tests
11 Intermediate inspection
12 Recovery
13 Final inspection
14 Failure criteria
15 information to be given in the relevant specifications
16 information to be given in the test report
Annex A (Informative) Guide
