BS ISO 8568-2008 Mechanical shock Testing machines Characteristics and performance《机械冲击 测试机 特征和性能》.pdf

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1、BRITISH STANDARD BS ISO 8568:2007 Mechanical shock Testing machines Characteristics and performance ICS 17.160; 19.060 BS ISO 8568:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2008 BSI 2007 ISBN 978 0 580 59442 7 National f

2、oreword This British Standard is the UK implementation of ISO 8568:2007. It supersedes BS 7347:1990 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee GME/21, Mechanical vibration, shock and condition monitoring, to Subcommittee GME/21/2, Vibration and s

3、hock measuring instruments and testing equipment. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance

4、with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. Date Comments Reference number ISO 8568:2007(E)INTERNATIONAL STANDARD ISO 8568 Second edition 2007-07-01 Mechanical shock Testing machines Characteristics and performance Chocs mcaniqu

5、es Machines dessai Caractristiques et performance BS ISO 8568:2007ii iii Contents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 2 4 Performance 2 4.1 General. 2 4.2 Operation principles. 2 4.3 Test types 3 4.4 Shock-testing machine components 3 5 Shock-testing mach

6、ine specification . 4 6 Requirements for shock-testing machines 5 6.1 General. 5 6.2 Safety requirements . 5 6.3 Table or carriage. 5 6.4 Hoisting or pre-loading 6 6.5 Braking systems . 6 6.6 Reaction mass. 6 6.7 Shock pulse-shaping devices and methods 7 7 Inspection of a shock-testing machine 7 7.1

7、 General. 7 7.2 Preparation procedure . 7 7.3 Example of an inspection procedure for a shock-testing machine operation . 8 Annex A (informative) Devices for shaping various pulse shapes . 10 Annex B (informative) Shock-response spectra, shock synthesis and analysis 12 Annex C (informative) Use of a

8、vibration generator for producing a shock pulse 15 Annex D (normative) Determination of uniformity of acceleration and relative transverse motion on the table of a shock-testing machine 20 Annex E (normative) Stray magnetic field. 22 Bibliography . 23 BS ISO 8568:2007iv Foreword ISO (the Internation

9、al Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been e

10、stablished has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standard

11、ization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for vo

12、ting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all su

13、ch patent rights. ISO 8568 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition monitoring, Subcommittee SC 6, Vibration and shock generating systems. This second edition cancels and replaces the first edition (ISO 8568:1989), which has been technically revised.

14、BS ISO 8568:20071 Mechanical shock Testing machines Characteristics and performance 1 Scope This International Standard specifies performance parameters and methods of inspection of mechanical shock-testing machines and gives guidelines for describing their characteristics. It is intended to ensure

15、that the potential user of a particular shock-testing machine is provided with an adequate description of the characteristics of the machine, and also to give guidance on the selection of such machines. This International Standard is applicable to the shock-testing machines that are used for demonst

16、rating or evaluating the effect of shock conditions representative of the service environment in accordance with the relevant part of IEC 60068 and also for diagnostic testing. The purpose of the shock test is to reveal mechanical weakness and/or degradation in specified performance. It can also be

17、used to determine the structural integrity of a test specimen or as a means of quality control. Machines used for simulation of earthquakes, sonic booms, explosions and implosions, bursting tests, metalworking, forming, etc. are not covered in this International Standard. Several techniques for gene

18、rating the desired shock motion are discussed. Both simple-pulse and complex transients can be produced. The simulation of transients can be achieved by control of the test with a specified shock-response spectrum. NOTE 1 Annex A gives a description of pulse-shaping devices. Annex B defines methods

19、of application of the shock response spectra. Annex C considers a method of evaluating the possibility of using a vibration generator for producing a shock pulse. Annexes D and E deal with the methods of measurement of some characteristics in inspection methods (or procedures) of shock-testing machi

20、nes. NOTE 2 Characteristics of vibration-generating equipment are covered in ISO 5344, ISO 6070 and ISO 8626. 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

21、, the latest edition of the referenced document (including any amendments) applies. ISO 2041:1990, Vibration and shock Vocabulary ISO 5347 (all parts), Methods for the calibration of vibration and shock pick-ups ISO 5348, Mechanical vibration and shock Mechanical mounting of accelerometers ISO 15261

22、, Vibration and shock generating systems Vocabulary ISO 16063 (all parts), Methods for the calibration of vibration and shock transducers IEC 60068-1:1988, Environmental testing Part 1: General and guidance IEC 60068-2-27:1987, Environmental testing Part 2: Tests Test Ea and guidance: Shock IEC 6006

23、8-2-81, Environmental testing Part 2-81: Tests Test Ei: Shock Shock response spectrum synthesis BS ISO 8568:20072 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 2041, ISO 15261 and the following apply. 3.1 check point fixing point nearest to the cen

24、tre of the table surface of the shock-testing machine, unless there is a fixing point having a more rigid connection to the table, in which case the latter point is used 3.2 nominal load maximum load used for the testing of a shock-testing machine as specified by the manufacturer 3.3 shock-testing m

25、achine device for subjecting a system to controlled and reproducible mechanical shock ISO 2041:1990, 3.23 NOTE Shock-testing machines can be classified as specially designed shock generators, gravity and powered, and vibration generators of electrodynamic and servo-hydraulic types used in a shock mo

26、de. 4 Performance 4.1 General The performance of a shock-testing machine is based on a relatively slow accumulation of energy used to reproduce a shock, and its consequent discharge in an energy-transducing device for a short period of time. The energy needed to create a shock may be achieved by the

27、 work against gravity (in free-fall machines) or, if the shock is in a direction other than upwards or if the free-fall machine does not provide enough velocity change, the necessary potential energy may be supplied by elastic cords, springs or hydraulic and pneumatic means. The shock can also be ac

28、hieved by releasing compressed gas, by explosives or by transfer of momentum from one moving mass to another. 4.2 Operation principles According to the principle used, shock-testing machines are classified as free-fall or accelerated shock-testing machines, or as gas guns or explosive guns, hydrauli

29、c and pneumatic, as well as servo-hydraulic and electrodynamic. The shock pulse (either a single-pulse or a transient vibration) is produced by a shock pulse-shaping device mounted on the table or carriage, on the reaction mass, or on both. A wide selection of pulse shapes can be produced depending

30、on how the kinetic energy is transferred by pulse-shaping devices. Annex A gives some guidelines on the selection of pulse-shaping devices. Pulse-shaping devices can be used in a rebounding or non-rebounding mode. Usually the device that attaches the test specimen is initially accelerated and a shoc

31、k is produced during the rebound of the test specimen. Sometimes (for large masses or when the acceleration of the test specimen during shock pre-history is undesirable) a reaction mass or a hammer can be initially accelerated and the shock is produced as a result of the impact between the reaction

32、mass and the device that attaches the test specimen. This mode is classified as non-rebounding. BS ISO 8568:20073 As an alternative to the shaping of the shock pulse, for electrodynamic or servo-hydraulic vibration generators, a shock-response spectrum of the impulse to be applied to the specimen ma

33、y be shaped to be similar to the required shock-response spectrum. When the test specification requires some tolerance for a test shock-response spectrum (e.g. +3 dB, 1,5 dB), electrodynamic and servo-hydraulic test equipment for generating vibration may also be used for shock testing. These machine

34、s can generate classical shock waveforms (half-sine, trapezoidal, saw-tooth, etc.) as well as arbitrary waveforms which have the required shock-response spectra, and are usually produced by means of digital control, but generally have limited velocity and displacement capability. A method for mainta

35、ining the above limitations is briefly treated in Annex C. Characteristics of vibration-generating equipment are covered in ISO 5344, ISO 6070 and ISO 8626. 4.3 Test types 4.3.1 Shock pulse generation Classical shock pulse shapes in accordance with IEC 60068-2-27 are generated with additional pre-pu

36、lse and post-pulse shaping to limit velocity and displacement. The amplitude of the pre-pulse and post-pulse shapes is limited to a small fraction of the primary pulse amplitude. 4.3.2 Shock-response spectrum generation A brief, low-level oscillatory transient impulse is typically applied to the spe

37、cimen. The shock-response spectrum is measured, compared with the desired shock-response spectrum, and the difference used to modify the shape of the next impulse. Typically, this process is repeated several times until the desired shock spectrum is achieved, and then an input transient impulse of t

38、he desired level is applied to the specimen. The desired shock spectrum may be either standardized (i.e. one of the shock spectra of Annex B) or the shock spectrum of a field environment. 4.4 Shock-testing machine components A shock-testing machine consists of the following: a) a rigid table or carr

39、iage with means of attaching test specimens and shock pulse-shaping devices; b) a set of guides that controls the movement of the carriage; c) a means for storing the potential energy necessary for imparting the shock, such as provisions for hoisting or preloading springs and cords attached to the c

40、arriage; d) a means for securing the carriage at a selected drop height or position, prior to initiation of the shock pulse; e) a release mechanism; f) a reaction mass or base upon which the carriage impacts; g) a pulse-shaping and rebound braking system, or means to generate and control the shock s

41、pectra; h) control equipment; i) shock-measuring system; j) auxiliary power, cooling and other equipment, as required. BS ISO 8568:20074 5 Shock-testing machine specification The motion of the table or carriage may be specified by shock-response spectra and/or time-history parameters. Depending on t

42、he type of shock-testing machine (specially designed shock generators or vibration generators used in a shock mode), where applicable, data together with tolerances, shall be given for the following items: a) available pulse shapes for free fall and accelerated tables; b) maximum velocity change; c)

43、 maximum displacement; d) range of reproducible shock-pulse peak accelerations versus pulse durations; e) initial or pre-pulse acceleration and final or post-pulse acceleration; f) minimum shock-pulse duration; g) frequency range of wavelets to reproduce a shock-response spectrum; h) shock-response

44、spectrum flatness with resolution in 1/3, 1/6 or 1/12 octave; i) maximum drop height, preload pressure or charge; j) tare mass of table or carriage and total moving mass; k) maximum allowable axial force of specimen-mounting screw; l) natural frequencies of the table or carriage; m) natural frequenc

45、ies of the machine on its foundation; n) required pressure and volume of gas and liquids; o) quantities and flow rates of fluid or gas for the operation of the machine; p) type of rebound braking system and braking force; q) size and overall dimensions of the machine and its parts, especially the ta

46、ble or carriage and its accessories; r) dimensions, mass and mounting method of reaction masses and floor-loading requirements; s) maximum size and mass of test specimen; t) mounting facilities for test specimen and transducers; u) number of shocks (shock pulses) possible per unit time, or, alternat

47、ively, minimum period between two shocks; v) specification of the shock-measuring system employed; w) centre of gravity of the table, plus the effect of any off-centre load; x) acceptable range of environmental conditions, i.e. temperature, humidity, etc. BS ISO 8568:20075 6 Requirements for shock-t

48、esting machines 6.1 General The performance of shock-testing machines shall be defined and specified by the manufacturer. Detailed installation, operation and maintenance instruction manuals shall be provided by the manufacturer. Instructions shall include requirements for periodic inspection, maint

49、enance and lubrication of the equipment. Signs of wear of replaceable components and possible structural failure shall be described by the manufacturer. Appropriate steps shall be proposed for replacing deteriorating pulse-shaping devices and for repairing leaks in the pneumatic and hydraulic systems. Application and mounting of test specimens, adapter plates and fixtures to the table or carriage shall be thoroughly described. The effects on th