1、 ISO 2017 Metallic materials Fatigue testing Axial force-controlled method Matriaux mtalliques Essais de fatigue Mthode par force axiale contrle INTERNATIONAL STANDARD ISO 1099 Third edition 2017-06 Reference number ISO 1099:2017(E) ISO 1099:2017(E)ii ISO 2017 All rights reserved COPYRIGHT PROTECTED
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3、itten permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO 109
4、9:2017(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Test plan 3 4.1 General outline 3 4.2 Presentation of fatigue results 4 4.2.1 General 4 4.2.2 Whler or S-N curve 4 4.2.3 Mean stress diagrams 4 5 Shape and size of specimen . 4 5.1 Form of specime
5、ns . 4 5.2 Specimen temperature measurement 5 6 Geometry 5 6.1 Bars and flat sheets 5 mm thick 5 6.2 Flat sheets . 6 6.2.1 General 6 6.2.2 Thicknesses between 5 mm and 2,5 mm 6 6.2.3 Thicknesses 2,5 mm 6 6.3 Preparation of specimens 6 6.3.1 Machining procedure . 7 6.3.2 Sampling and marking 7 6.3.3
6、Surface condition of the specimen . 7 6.3.4 Dimensional checks . 8 6.3.5 Storage and handling . 8 7 Apparatus . 8 7.1 Test machine . 8 7.2 Alignment check 9 7.3 Force transducer 9 7.4 Gripping of specimen. 9 8 Instrumentation for test monitoring 10 8.1 Recording systems 10 8.2 Cycle counter .10 9 Ch
7、ecking and v erification.10 10 Mounting of specimen 10 11 Rate of testing .10 12 Application of force.11 13 Recording of temperature and humidity11 14 Criterion of failure and test termination11 14.1 Criterion of failure .11 14.2 Test termination .11 15 Test report 11 Bibliography .23 ISO 2017 All r
8、ights reserved iii Contents Page ISO 1099:2017(E) Foreword ISO (the International 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
9、 member body interested in a subject for which a technical committee has been established 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 Internationa
10、l Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different
11、types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall
12、not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents). Any trade name used in this document
13、is information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformit y assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Tec
14、hnical Barriers to Trade (TBT) see the following URL: www . i s o .org/ iso/ foreword .html This document was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee SC 5, Fatigue testing. This third edition cancels and replaces the second edition (ISO 1099:2006), whic
15、h has been technically revised. It shall be noted that this document does not address safety or health concerns, should such issues exist, that may be associated with its use or application. The user of this document has the sole responsibility to establish any appropriate safety and health concerns
16、 as well as to determine the applicability of any national or local regulatory limitations regarding the use of this document.iv ISO 2017 All rights reserved ISO 1099:2017(E) Introduction This document is intended to provide guidance for conducting axial, constant-amplitude, force- controlled, cycli
17、c fatigue tests on specimens of a metal for the sake of generating fatigue-life data (i.e. stress vs. cycles to failure) for material characterization. Nominally identical specimens are mounted in an axial force-type fatigue-testing machine and subjected to the required cyclic force conditions that
18、introduce any one of the types of cyclic stress as illustrated in Figure 1. The test waveform should be of constant amplitude and sinusoidal unless otherwise specified. The force being applied to the specimen is along the longitudinal axis passing through the centroid of each cross-section. The test
19、 is continued until the specimen fails or until a predetermined number of stress cycles have been exceeded (See Clauses 4 and 13). Tests are typically conducted at ambient temperature (ideally between 10 C to 35 C). NOTE The results of a fatigue test can be affected by atmospheric conditions and whe
20、re controlled conditions are required, ISO 554:1976, 2.1 applies. ISO 2017 All rights reserved v Metallic materials Fatigue testing Axial force- controlled method 1 Scope This document specifies the conditions for conducting axial, constant-amplitude, force-controlled, fatigue tests at ambient tempe
21、rature on metallic specimens, without deliberately introduced stress concentrations. The object of testing while employing this document is to provide fatigue information, such as the relation between applied stress and number of cycles to failure for a given material condition, such as hardness and
22、 microstructure, at various stress ratios. While the form, preparation and testing of specimens of circular and rectangular cross-section are described, component testing and other specialized forms of testing are not included in this document. NOTE 1 Fatigue tests on notched specimens are not cover
23、ed by this document since the shape and size of notched test pieces have not been standardized. However, fatigue-test procedures described in this document can be applied to fatigue tests of such notched specimens. NOTE 2 Throughout this document, the engineering stress is employed. Engineering stre
24、ss is defined as the quotient of the axially applied force to the cross-sectional area of the test specimen, S = Force/Area, at the test temperature. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of
25、 this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 4965-1, Metallic materials Dynamic force calibration for uniaxial fatigue testing Part 1: Testing systems ISO 7500-1, Me
26、tallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system ISO 23788, Metallic materials Verification of the alignment of fatigue testing machines 3 T erms a nd definiti ons For the purpose
27、s of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p :/ www .iso .org/ o
28、bp 3.1 test specimen diameter d diametric distance or width of the specimen or test piece where the stress is at a maximum 3.2 grip diameter D diameter of the specimen at grip end INTERNATIONAL ST ANDARD ISO 1099:2017(E) ISO 2017 All rights reserved 1 ISO 1099:2017(E) 3.3 thickness of test section t
29、 thickness of reduced section of rectangular test specimen 3.4 width of test section w width of reduced section of rectangular test specimen 3.5 parallel length L p length in the gauge test section of a specimen or test piece that has equal test diameter or test width and is parallel 3.6 specimen le
30、ngth L z overall length of test specimen 3.7 f ill e t ra di us r radius between the parallel length and the grip end of test specimen Note 1 to entry: The curve need not be a true arc of a circle over the whole of the distance between the end of the parallel length and the start of the grip end. 3.
31、8 maximum stress S max greatest algebraic value of stress in a stress cycle Note 1 to entry: See Figure 2. 3.9 mean stress S m one-half the algebraic sum of the maximum stress and the minimum stress in a stress cycle Note 1 to entry: See Figure 2. 3.10 minimum stress S min least algebraic value of s
32、tress in a stress cycle Note 1 to entry: See Figure 2. 3.11 stress amplitude S a one-half the algebraic difference between the maximum stress and the minimum stress Note 1 to entry: See Figure 2.2 ISO 2017 All rights reserved ISO 1099:2017(E) 3.12 stress range S algebraic difference between the maxi
33、mum and minimum stress S = S max S min Note 1 to entry: See Figure 2. 3.13 stress ratio R s ratio of minimum to maximum stress during any single cycle of fatigue operation R s= S min /S max Note 1 to entry: See Figure 2. 3.14 stress cycle variation of stress with time, repeated periodically and iden
34、tically Note 1 to entry: See Figure 2. 3.15 number of cycles N number of smallest segments of the force-time, stress-time, etc., function that is repeated periodically 3.16 fatigue life N f number of applied cycles to achieve a defined failure criterion 3.17 fatigue strength at N cycles S N value of
35、 the stress amplitude at a stated stress ratio under which the specimen would have a life of N cycles 4 Test plan 4.1 General outline Before commencing testing, the following shall be agreed by the parties concerned, unless specified otherwise in the relevant product standard: a) the form of specime
36、n to be used (see 5.1); b) the R-ratio(s) to be used; c) the objective of the tests, i.e. which of the following is to be determined: the fatigue life at a specified stress amplitude; the fatigue strength at a specified life; a full Whler or S-N curve. d) the number of specimens to be tested and the
37、 testing sequence; ISO 2017 All rights reserved 3 ISO 1099:2017(E) e) the number of cycles at which a test on an un-failed specimen shall be terminated; f) the testing temperature if different from the requirements given in 5.2. In the light of recent research, it is of importance to note that metal
38、s generally do not exhibit a “fatigue limit” per se, that is, a stress below which the metal will endure an “infinite number of cycles”. Typically, the “plateau(s)” in stress-life are referred to as the conventional “fatigue limit(s)”, but failures below these levels have been reported and do occur.
39、 See, for example, References 6 to9. 4.2 Presentation of fatigue results 4.2.1 General The design of the investigation and the use to be made of the results, govern the choice of the most suitable method of presenting the results from the many available, graphically and otherwise. The results of fat
40、igue tests are usually presented graphically. In reporting fatigue data, the test conditions should be clearly defined. In addition to graphical presentations, tabulated numerical data are desirable where the presentation format permits. 4.2.2 Whler or S-N curve The most general method of presenting
41、 the results graphically is to plot the number of cycles to failure, N, as abscissa and the values of stress amplitude or, depending on the type of stress cycle, those of any other stress, as ordinate. The curve drawn smoothly as an approximate middle line through the experimental points is called a
42、 Whler or S-N curve. A logarithmic scale is used for the number of cycles and the choice of whether a linear or logarithmic scale is used for the stress axis lies with the experimenter. Individual curves are plotted for each set of tests for each R-ratio. Experimental results are usually plotted on
43、the same figure. An example of these graphical representations is shown in Figure 3, where a linear stress scale is used. 4.2.3 Mean stress diagrams The fatigue strengths derived from the Whler or S-N curve are plotted in fatigue strength diagrams as constant life lines. The results can be represent
44、ed by a graph giving directly, for particular fatigue lives, the stress amplitude against the mean stress, as shown in Figure 4; or by plotting the maximum and minimum stresses against the mean stress, as shown in Figure 5; or by plotting the maximum stress against the minimum stress, as shown in Fi
45、gure 6. Experimental results may be plotted on the same figure. 5 Shape and size of specimen 5.1 Form of specimens Generally, a specimen having a fully machined test section is of the type shown in Figure 7 for a smooth cylindrical-type gauge section. The specimens may be of the following: circular
46、cross-section with tangentially blending fillets between the test section and the ends, or with a continuous radius between the ends (i.e. “hourglass” specimen); rectangular cross-section of uniform thickness over the test section with tangentially blending fillets between the test section and the g
47、ripped ends (see Figure 8). Specimens commonly known as “hourglass” specimens may be employed for testing with caution. In such specimens, there is a continuous radius between grip ends with a minimum diameter or width of the test section centrally located between these ends for cylindrical and flat
48、 specimens respectively. Unlike a smooth, constant diameter or width, gauge section where a volume of material is equally under stress, the hourglass specimen permits sampling only of a thin planar element of material at 4 ISO 2017 All rights reserved ISO 1099:2017(E) the minimum cross section. Thus
49、, the fatigue results produced may not represent the response of the bulk material where, particularly in the long-life fatigue regime, inclusions govern behaviour in high hardness metals and there is a duality in crack initiation from surface to subsurface 9 . In fact, such results may be non-conservative particularly in the longer life regime where the largest micro discontinuity may not lie in the planar section of greatest stress. It is important to note that for specimens of rectangular cros
