December 2012 DIN DIN 743-4 ICS 21.120.10 Calculation of load capacity of shafts and axles - Part 4: Fatigue limit, endurance limit - Equivalently damaging continuous stress, English translation of DIN 743-4:2012-12 Tragfahigkeitsberechnung von Wellen und Achsen - Teil 4: Zeitfestigkeit, Dauerfestigkeit - Schadigungsaquivalente Spannungsamplitude, Englische Ubersetzung von DIN 743-4:2012-12 Calcul de la capacité des arbres et axes - Partie 4: Résistance a la fatigue pour une durée de vie limitee, résistance a la fatigue pour une durée de vie illimitée - Amplitude de contrainte pour endommagement équivalent, Traduction anglaise de DIN 743-4:2012-12 Document comprises 11 pages Translation by DIN-Sprachendienst. In case of doubt, the German-language original shall be considered authoritative. No part of this translation may be reproduced without prior permission of English price group 8 www.din.de has the exclusive right of sale for German Standards (DIN-Normen). www.beuth.de 08.15 2096511 DIN 743-4:2012-10 A comma is used as the decimal marker. Contents Page Foreword 1 Scope 2 Normative references 3 Symbols, designations and units.... 4 Calculation... 4.1 General... 4.2 Single direction of loading.. 4.2.1 Calculation of safety factor for time-constant amplitude in the limited life strength domain .... 4.2.2 Calculation of safety factor for load spectra in the limited life strength and fatigue strength domains. 4.3 Combined loads ..... Bibliography Figures Figure 1 - Limited life strength value ANK Figure 2 - Method according to Miner - extended 2 DIN 743-4:2012-10 Foreword This standard has been prepared by Working Committee NA 060-34-32 AA Wellen- und Welle-Nabe- Verbindungen of Section Antriebstechnik of the Normenausschuss Maschinenbau (Mechanical Engineering Standards Committee) in DIN. DIN 743, Calculation of load capacity of shafts and axles comprises: Part 1: General Part 2: Theoretical stress concentration factors and fatigue notch factors Part 3: Strength of materials Part 4: Fatigue limit, endurance limit - Equivalently damaging continuous stress Supplement 1: Examples to part 1 to 3 Supplement 2: Examples to part 4 3 DIN 743-4:2012-10 Scope This standard applies to the calculation and verification of the safety of shafts and axles, in accordance with DIN 743-1, in the limited life strength domain (fatigue failure) as well as in the limited life strength and fatigue strength domains for load spectrum loading. Users can make use of their own verified experience or results. 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. DIN 743-1, Calculation of load capacity of shafts and axles — Part 1: General 3 Symbols, designations and units Symbol Designation Unit Dm Miner sum i Load bin of the load spectrum i Number of load spectrum bins Kk Load spectrum factor K Corrected number of load spectrum bins ne Corrected number of load cycles in bin k ni Number of load cycles in bin i Np Salient point of the Wohler curve between the limited life strength and fatigue strength domains NL Required number of load cycles N* Reference number of load cycles Ns Salient point of the Wohler curve between the quasi-static strength and the limited life strength domain Exponent of the Wohler curve q s Safety of the component Smin Required minimum safety of the component Shape of the load spectrum v Fatigue strength value N/mm2 Ozd,bADK, TADK Limited life strength value N/mm2 Ozd,bANK, TtANK 4 DIN 743-4:2012-10 Equivalent damaging stress amplitude N/mm2 Ozd,ba, Tta Stress amplitude of load bin i N/mm2 Ozd,bai, Tai Maximum stress amplitude of the given load spectrum N/mm2 Ozd,ba1, Tta1 So. St Single safety Subscripts Bending b Torsion t, t zd Tension/compression Tension/compression, bending Calculation 4.1 General effective lo