Detail of GB/T 2423.56-2018

Introduction of GB/T 2423.56-2018

1 Scope This part of GB/T 2423 provides the test methods for specimens to resist dynamic loads without unacceptable degradation of its functional and/or structural integrity when subjected to the specified random vibration test requirements. Broadband random vibration may be used to identify accumulated stress effects and the resulting mechanical weakness and degradation in the specified performance. This information, in conjunction with the relevant specification, may be used to assess the acceptability of specimens. This standard is applicable to specimens which may be subjected to vibration of a stochastic nature resulting from transportation or operational environments, for example in aircraft, space vehicles and land vehicles. It is primarily intended for unpackaged specimens, and for items in their transportation container when the latter may be considered as part of the specimen itself. However, if the item is packaged, then the item itself is referred to as a product. This standard may be used in conjunction with IEC 60068-2-47:2005, for testing packaged products If the specimens are subjected to vibration of a combination of random and deterministic nature resulting from transportation or real life environments, for example in aircraft, space vehicles and for items in their transportation container, testing with pure random may not be sufficient. See GB/T 2424.26—2008 for estimating the dynamic vibration environment of the specimen and based on that, selecting the appropriate test method. Although primarily intended for electro technical specimens, this standard is not restricted to them and may be used in other fields where desired (see Annex A). 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 2423.43—2008 Environmental testing for electric and electronic products - Part 2: Test methods - Mounting of specimens for vibration impact and similar dynamic tests (IEC 60068-2-47: 2005, IDT) GB/T 2424.26—2008 Environmental testing - Supporting documentation and guidance - Selecting amongst vibration tests (IEC 60068-3-8: 2003, IDT) IEC 60050-300 International electrotechnical vocabulary- Electrical and electronic measurements and measuring instruments - Part 311: General terms relating to measurements-Part 312: General terms relating to electrical measurements- Part 313: Types of electrical measuring instruments - Part 314: Specific terms according to the type of instrument) IEC 60068-1 Environmental testing—Part 1: General and guidance IEC 60068-2-6 Environmental testing—Part 2-6: Tests—Test Fc: Vibration (sinusoidal) IEC 60068-5-2 Environmental testing—Part 5-2: Guide to drafting of test methods—Terms and definitions Guide to drafting of test methods—Terms and definitions) IEC 60721-3 (all parts) Classification of environmental conditions—Part 3: Classification of groups of environmental parameters and their severities IEC Guide 104 The preparation of safety publications and the use of basic safety publications and group safety publications ISO 2041 Vibration and shock—Vocabulary 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. Note: the terms used are generally defined in IEC 60050-300, IEC 60068-1, IEC 60068-2-6, and IEC 60068-5-2 and ISO 2041. If a definition from one of those sources is included here, the derivation is indicated and departures from the definitions in those sources are also indicated. 3.1 cross-axis motion motion not in the direction of the stimulus; generally specified in the two axes orthogonal to the direction of the stimulus Note: the cross-axis motion shall be measured close to the fixing points. 3.2 actual motion motion represented by the wide band signal returned from the reference point transducer 3.3 fixing point part of the specimen in contact with the fixture or vibration table at a point where the specimen is normally fastened in service Note: if a part of the real mounting structure is used as the fixture, the fixing points are taken as those of the mounting structure and not of the specimen. 3.4 control methods 3.4.1 single point control control method using the signal from the transducer at the reference point in order to maintain this point at the specified vibration level 3.4.2 multipoint control control method using the signals from each of the transducers at the checkpoints Note: the signals are either continuously averaged arithmetically or processed by using comparison techniques, depending upon the relevant specification. See 3.13. 3.5 gn standard acceleration due to the earth's gravity, which itself varies with altitude and geographical latitude Note: for the purposes of this standard, the value of g n is rounded up to the nearest whole number, that is 10m/s2. 3.6 measuring points Specific points at which data are gathered conducting the test Note: these points are of three types, as defined in 3.7 to 3.9.

Contents of GB/T 2423.56-2018

Foreword I Introduction V 1 Scope 2 Normative references 3 Terms and definitions 4 Requirements for test apparatus 4.1 General 4.2 Basic motion 4.3 Cross-axis motion 4.4 Mounting 4.5 Measuring systems 4.6 Vibration tolerances 4.7 Control strategy 4.8 Vibration response inspection 5 Severities 5.1 Test frequency range 5.2 RMS value of acceleration 5.3 Shape of acceleration spectral density curve 5.4 Test duration 6 Preconditioning 7 Initial measurements and functional performance test 8 Testing 8.1 General 8.2 Initial vibration response investigation 8.3 Low-level excitation for equalization prior to testing 8.4 Random testing 8.5 Final vibration response investigation 9 Recovery 10 Final measurements and functional performance 11 Information to be given in the relevant specification Annex A (Informative) Standardized test spectra Annex B (Informative) Guidance Bibliography