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1、 Reference number ISO 14347:2008(E) ISO 2008 INTERNATIONAL STANDARD ISO 14347 First edition 2008-12-01 Fatigue Design procedure for welded hollow-section joints Recommendations Fatigue Procdure de dimensionnement la fatigue des assemblages souds de profils creux Recommandations Copyright Internation
2、al Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14347:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In acc
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5、nting. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2008 All rights reserved. Unless otherwi
6、se specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright o
7、ffice Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/591
8、0770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14347:2008(E) ISO 2008 All rights reserved iii Contents Page Foreword iv 1 Scope1 1.1 General .1 1.2 Materials.1 1.3 Types of joints .1 2 Normative references1 3 Terms and defini
9、tions.2 4 Symbols and abbreviated terms7 5 Cumulative fatigue damage12 6 Partial safety factor .12 7 Fatigue design procedures.12 7.1 Hot-spot stress method12 7.2 Design procedures13 8 Fatigue strength 13 8.1 Member forces.13 8.2 Nominal stress ranges14 8.3 SCF calculations14 8.4 Hot-spot stress ran
10、ges .14 8.5 Fatigue strength curves15 9 SCF calculations for CHS joints 17 9.1 Uniplanar CHS T- and Y-joints .17 9.2 Uniplanar CHS X-joints.18 9.3 Uniplanar CHS K-joints with gap .18 9.4 Multiplanar CHS XX-joints19 9.5 Multiplanar CHS KK-joints with gap20 9.6 Minimum SCF values 21 10 SCF calculation
11、s for RHS joints 21 10.1 Uniplanar RHS T- and X-joints .21 10.2 Uniplanar RHS K-joints with gap .22 10.3 Uniplanar RHS K-joints with overlap.23 10.4 Multiplanar RHS KK-joints with gap24 10.5 Minimum SCF values 25 Annex A (normative) Quality requirements for hollow sections26 Annex B (normative) Weld
12、 details.27 Annex C (informative) A fatigue assessment procedure29 Annex D (normative) SCF equations and graphs for CHS joints.31 Annex E (normative) SCF equations and graphs for RHS joints.47 Bibliography67 Copyright International Organization for Standardization Provided by IHS under license with
13、ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14347:2008(E) iv ISO 2008 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national st
14、andards 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 established has the right to be represented on that committee. International o
15、rganizations, 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 standardization. International Standards are drafted in accordance with the rules giv
16、en 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 voting. Publication as an International Standard requires approval by at least
17、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 such patent rights. ISO 14347 was prepared by the International Institute of We
18、lding, Commission XV, Design, analysis and fabrication of welded structures, recognized as an international standardizing body in the field of welding in accordance with Council Resolution 42/1999. Requests for official interpretations of any aspect of this International Standard should be directed
19、to the ISO Central Secretariat, who will forward them to the IIW Secretariat for an official response. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking pe
20、rmitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 14347:2008(E) ISO 2008 All rights reserved 1 Fatigue Design procedure for welded hollow-section joints Recommendations 1 Scope 1.1 General This International Standard gives recommendations for the design and analysis of unstiffened, w
21、elded, nodal joints in braced structures composed of hollow sections of circular or square shape (with or without rectangular chord) under fatigue loading. This International Standard applies to structures: a) fulfilling quality requirements for hollow sections (see Annex A); b) complying with recom
22、mended weld details (see Annex B); c) employing permitted steel grades (see 1.2); d) having hollow section joints (see 1.3); e) having either 1) square or rectangular hollow sections with a thickness between 4 mm and 16 mm, or 2) circular hollow sections with a thickness between 4 mm and 50 mm; f) h
23、aving as stress range the range of “hot-spot” stress; g) having identical brace (branch) members. 1.2 Materials This International Standard applies to both hot-finished and cold-formed steel structural hollow sections, complying with the applicable national manufacturing specification, that fulfil s
24、pecified quality requirements (see Annex A). 1.3 Types of joints This International Standard applies to joints consisting of circular hollow sections (CHS) or rectangular hollow sections (RHS) as used in uniplanar or multiplanar trusses or girders, such as T-, Y-, X-, K-, XX-, and KK-joints (see Fig
25、ure 1 and Figure 2). 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. ISO 6
26、30:1995, Structural steels Plates, wide flats, bars, sections and profiles Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without license from
27、 IHS -,-,- ISO 14347:2008(E) 2 ISO 2008 All rights reserved a) CHS T-joints b) CHS Y-joints c) CHS X-joints d) CHS K-joints with gap e) RHS T-joints f) RHS X-joints g) RHS K-joints with gap h) RHS K-joints with overlap NOTE RHS are assumed to be square, although this International Standard is likely
28、 to be applicable to rectangular chord members, welded to square branch members. Figure 1 Types of uniplanar joints covered by this International Standard a) CHS XX-joints b) CHS KK-joints with gap c) RHS KK-joints with gap NOTE RHS are assumed to be square, although this International Standard is l
29、ikely to be applicable to rectangular chord members, welded to square branch members. Figure 2 Types of multiplanar joints covered by this International Standard 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 brace branch welded hollow secti
30、on joints cut and welded member See Figure 3. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14347:2008(E)
31、ISO 2008 All rights reserved 3 Key 1 load applied in the branch 2 crown point 3 branch 4 saddle point 5 weld 6 chord a) Joint nomenclature Key 1 chord wall 2 stress increase due to weld geometry 3 brace hot-spot stress 4 weld toe 5 extrapolation of geometric stress distribution to weld toe 6 stress
32、in branch 7 nominal stress 8 increase in stress due to overall joint geometry 9 branch wall 10 weld b) Stress distribution in branch Figure 3 Hot-spot stress definition in nodal joints Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/
33、5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14347:2008(E) 4 ISO 2008 All rights reserved Key 1 chord wall 2 stress increase due to weld geometry 3 chord hot-spot stress 4 weld toe 5 extrapolation of geometric stress dis
34、tribution to weld toe 6 stress in chord 7 nominal stress 8 increase in stress due to overall joint geometry 9 branch wall c) Stress distribution in chord Figure 3 (continued) 3.2 constant amplitude fatigue limit welded hollow section joints stress range for a specific S-N curve when the number of cy
35、cles, N, is 5 million or greater 3.3 cut-off limit stress range for a specific S-N curve when the number of cycles, N, is 100 million or greater, used in the assessment of fatigue under variable amplitude loading 3.4 fatigue deterioration of a component due to the initiation and growth of cracks und
36、er fluctuating loads 3.5 fatigue life endurance Nf number of applied cycles to achieve a defined failure criterion ISO 1099:2006, 3.14 NOTE In this International Standard, crack growth through the wall thickness is considered as failure. 3.6 gap length g distance measured along the length of the con
37、necting face of the chord between the toes of the adjacent brace members See Figure 4. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without
38、license from IHS -,-,- ISO 14347:2008(E) ISO 2008 All rights reserved 5 Key 1 member (overlapping in the lower diagram) 2 optionally overlapped member NOTE For variable definitions, see Clause 4. Figure 4 Definition of gap g and overlap q 3.7 hot-spot stress welded hollow section joints point along
39、the weld vicinity where the extrapolated primary stress has its maximum value (i.e. the maximum geometric stress) NOTE This definition differs from the more general definition of hot-spot stress as the structural stress at the weld toe. The extrapolation is carried out from the region outside the in
40、fluence of the effect on the stress of geometric discontinuities due to the joint configuration, but close enough to fall inside the zone of the stress gradient caused by the global geometrical effects of the connection. The extrapolation is carried out on the branch or brace (cut and welded member)
41、 side and the chord (continuous member) side of each weld (see Figure 3). The hot-spot stress can be determined by considering the stress perpendicular to the weld toe for the chord and the stress parallel to the brace axis for the brace. 3.8 nominal stress welded hollow section joints maximum stres
42、s in a cross-section calculated on the actual cross-section by simple elastic theory without taking into account the effect of geometrical discontinuities due to the joint configuration on the stress Copyright International Organization for Standardization Provided by IHS under license with ISO Lice
43、nsee=Boeing Co/5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 14347:2008(E) 6 ISO 2008 All rights reserved 3.9 overlap Ov ratio of the overlap length, q, to the projected connecting length to chord of overlapping brace, p
44、NOTE The overlap is expressed as a percentage. See Figure 4, where b1 = h1 = h2, t1 = t2, and 1 = 2. See Clause 4 for the variable definitions. 3.10 S-N curve curve giving the relation between the stress range and the number of cycles to failure NOTE 1 Conventionally, the range of stress is plotted
45、on the vertical axis and the number of cycles on the horizontal axis using logarithmic scales for both axes. NOTE 2 The S-N curves given in this International Standard have been derived from a statistical analysis of relevant experimental data and represent lives that are less than the mean life by
46、two standard deviations of lg N. 3.11 stress concentration factor SCF Kt welded hollow section joints ratio between the hot-spot stress at the joint and the nominal stress in the member due to a basic member load that causes this hot-spot stress NOTE In joints with more than one branch, each branch
47、is considered. Generally, stress concentration factors are calculated for the chord and branch. 3.12 stress range S arithmetic difference between the maximum and minimum stress S = Smax Smin NOTE 1 Adapted from ISO 1099:2006, 3.10. NOTE 2 The nominal stress range is based on the nominal stresses whi
48、le the hot-spot stress range is based on hot- spot stresses. See Figure 5. Key S tensile stress S compressive stress Figure 5 Stress range, S, and stress ratio, R Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 01/31/2009 00:55:56 MSTNo reproduction or networking permitted without license from IH