December 2012 DIN DIN 743-2 ICS 21.120.10 Supersedes DIN 743-2:2000-10 Calculation of load capacity of shafts and axles - Part 2: Theoretical stress concentration factors and fatigue notch factors, English translation of DIN 743-2:2012-12 Tragfahigkeitsberechnung von Wellen und Achsen - Teil 2: Formzahlen und Kerbwirkungszahlen, Englische Ubersetzung von DIN 743-2:2012-12 Calcul de la capacité des arbres et axes - Partie 2: Coefficients théoriques de la concentration des contraintes, coefficients effectifs de la concentration des contraintes, Traduction anglaise de DIN 743-2:2012-12 Document comprises 34 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 15 DiN Deutsches Institut fur Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany, www.din.de has the exclusive right of sale for German Standards (DIN-Normen). www.beuth.de 08.15 2096510 DIN 743-2:2012-12 A comma is used as the decimal marker. Contents Page 1 Scope. 2 Normative reference 3 Symbols, designations and units... Fatigue notch factor ... 4 4.1 Definition of fatigue notch factor 4.2 Experimentally determined fatigue notch factors . 6 4.2.1 Parallel keyway and interference fit...... 4.2.2 Fatigue notch factors for splined shafts, serrated shafts and involute spline shafts 4.2.3 Fatigue notch factors for round bars with V-notch..... 10 4.2.4 Fatigue notch factors for circumferential rectangular notch .. 11 4.3 Fatigue notch factors for notches with known stress concentration factor... 4.3.1 Shoulder, U-notch, shoulder with undercut, transverse hole ..... 4.3.2 Notch cases not yet dealt with.... 14 5 Stress concentration factors .. 5.1 Definition of stress concentration factor .... .14 5.2 Stress concentration factors for different notch shapes 5.2.1 Shoulder and U-notch 15 5.2.2 Shoulder with undercut.. 22 5.2.3 Transverse hole .. 6 Size influence factors .. 6.1 .24 General information.. 6.2 Technological size influence factor K,(deff) 24 6.3 Geometrical size influence factor K2(d).... 26 6.4 Geometrical size influence factor K3(d) .. 27 Influence factor for surface roughness KFo. 7 ...28 8 Influence factor for surface conditioning Ky Bibliography ..... Figures Figure 1 Fatigue notch factors for splined shafts, serrated shafts and involute spline shafts ........ 8 Figure 2 - Fatigue notch factors for round bars with circumferential V-notch [2]. ..10 Figure 3 Circumferential rectangular notch for circlips according to DiN 471 and structural radius p* according to Neuber [9] .... Figure 4 Sensitivity factor n .... Figure 5 Stress concentration factors for notched round bars in tension .... Figure 6 - Stress concentration factors for notched round bars in bending .. Figure 7 Stress concentration factors for notched round bars in torsion .... Figure 8 Stress concentration factors for shouldered round bars in tension ... Figure 9 - Stress concentration factors for shouldered round bars in bending.... 20 Figure 1o Stress concentration factors for shouldered round bars in torsion . 21 2 DIN 743-2:2012-12 Figure 11 Shoulder with undercut. 22 Figure 12 Stress concentration factors for round bars with transverse hole in tension/ compression, bending or torsion (tension/compression [2], bending and torsion [1]) 23 Figure 13 - Technological size influence factor Ki(deff) . ...25 Figure 14 Geometrical size influence factor K2(d) 26 Figure 15 Geometrical size influence factor K3(d) . ..27 Figure 16 Influence factor for surface roughness Ke Figure 17 Influence factor for surface conditioning, Ky, in chemico-thermal processes .. Figure 18 Influence factor for surface conditioning, Ky, in mechanical processes . .32 Figure 19 Influence factor for surface conditioning, Ky, in thermal processes Tables Table 1 - Fatigue notch factors o.t (dbk) for shaft-hub connections Table 2 - Relative stress grad