The stress field parameters, namely the notch stress intensity factors (N-SIFs) according to a more recent definition, can be used to predict the fatigue behaviour of mechanical components weakened by V-shaped re-entrant corners, where the singularity in the stress distribution makes any failure criterion based on the elastic peak stress no longer applicable. When the notch root radius is small but different from zero, the N-SIF can still be used, since a comprehensive analytical approach is available for open sharp and blunt notches. The fatigue strength reduction factor can be given as a function both of the elastic peak stress (only if it has a finite value) and of the N-SIF (for every notch tip radius value), by assuming that the fatigue strength of notched elements depends on a mean stress value in the critical zone.
The welded joints are an example of practical N-SIF use in fatigue strength prediction. In this case not only the fatigue crack initiation life but also the fatigue crack propagation phase are strictly correlated to the N-SIF value for the reason that the residual life is mainly dependent on crack propagation in the zone just governed by N-SIFs.
WilliamsM. L.Stress singularities resulting from various boundary conditions in angular corners of plates in extension. J. Appl. Mechanics, 1952, 19, 526–528.
2.
BogyD. B.Edge-bonded dissimilar orthogonal elastic wedges under normal and shear loading. J. Appl. Mechanics, 1968, 35, 460–466.
3.
BogyD. B.Two edge-bonded elastic wedges of different materials and wedge angles under surface tractions. J. Appl. Mechanics, 1971, 38, 377–386.
4.
EnglandA. H.On stress singularities in linear elasticity. Int. J. Engng Sci., 1971, 9, 571–585.
5.
KellyP. A.HillsD. A.NowellD.The design of joints between elastically dissimilar components. J. Strain Analysis, 1992, 27, 15–20.
6.
GrossR.MendelsonA.Plane elastostatic analysis of V-notched plates. Int. J. Fracture Mechanics, 1972, 8 (3), 267–276.
7.
CarpenterW. C.A collocation procedure for determining fracture mechanics parameters at a corner. Int. J. Fracture, 1984, 24, 255–266.
8.
CarpenterW. C.Mode I and mode II stress intensities for plates with cracks of finite opening. Int. J. Fracture, 1984, 26, 201–214.
9.
ChenD. H.NisitaniH.Singular stress field near the corner of jointed dissimilar materials. J. Appl. Mechanics, 1993, 60, 607–613.
10.
ChenD. H.Stress intensity factors for V-notched strip under tension or in-plane bending. Int. J. Fracture, 1995, 70, 81–97.
11.
AkisanyaA. R.On the singular stress field near the edge of bonded joints. J. Strain Analysis, 1997, 32, 301–311.
12.
SinclairG. B.OkajimaM.GriffinJ. H.Path independent integral for computing stress intensity at sharp notches in elastic strip. Int. J. Numer. Meth. Engng, 1984, 20, 999–1008.
13.
SinclairG. B.A remark on the determination of mode I and mode II stress intensity factors for sharp re-entrant corners. Int. J. Fracture, 1985, 27, R81–R85.
14.
AtkinsonC.BasteroJ. M.Martinez-EsnadaJ. M.Stress analysis in sharp angular notches using auxiliary fields. Engng Fracture Mechanics, 1988, 31, 637–646.
15.
HydeT. H.SunW.Stress singularities at the free surface of an axisymmetric two-material creep test specimen. J. Strain Analysis, 1997, 32 (2), 107–117.
16.
GradinP. A.A fracture criterion for edge-bonded bi-material bodies. J. Composite Mater., 1982, 16, 448–456.
17.
ReedyE. D.JrIntensity of stress singularity at the interface-comer between a bonded elastic and rigid layer. Engng Fracture Mechanics, 1990, 36, 575–583.
18.
ReedyE. D.JrAsymptotic interface-corner solutions for butt tensile joints. Int. J. Solids Structs, 1993, 30, 767–777.
19.
ReedyE. D.JrGuessT. R.Comparison of butt tensile strength data with interface corner stress intensity factor prediction. Int. J. Solids Structs, 1993, 30, 2929–2936.
20.
CarpinteriA.Stress singularity and generalised fracture toughness at the vertex of re-entrant corners. Engng Fracture Mechanics, 1987, 26, 143–155.
21.
KneslZ.A criterion of V-notch stability. Int. J. Fracture, 1991, 48, R79–R83.
22.
NuiL. S.ChehimiC.PluvinageG.Stress field near a large blunted tip V-notch and application of the concept of the critical notch stress intensity factor (NSIF) to the fracture toughness of very brittle materials. Engng Fracture Mechanics, 1994, 49, 325–335.
23.
SewerynA.Brittle fracture criterion for structures with sharp notches. Engng Fracture Mechanics, 1996, 47, 673–681.
24.
FettT.Failure of brittle materials near stress singularities. Engng Fracture Mechanics, 1996, 53, 518–551.
25.
DunnM. L.SuwitoW.CunninghamS. J.Fracture initiation at sharp notches: Correlation using critical stress intensities. Int. J. Solids Structs, 1997, 34, 3873–3883.
26.
DunnM. L.SuwitoW.CunninghamS. J.MayC. W.Fracture initiation at sharp notches under mode I, mode II, and mild mixed mode loading. Int. J. Fracture, 1997, 84, 367–381.
AtzoriB.Notch effect or linear elastic fracture mechanics in fatigue design (in Italian). In Proceedings of the 13th AIAS Conference, Bergamo, Italy, 1985, pp. 294–307.
29.
AtzoriB.PappalettereC.A method for the evaluation of the fatigue strength of mechanical structures with sharp notches is applied to the design of a single lap joint using numerical and experimental techniques. In Proceedings (Supplementary Papers) of the International Conference onFatigue of Engineering Materials and Structures, Sheffield, 1986, pp. 1–6.
30.
LazzarinP.Influence of welded joints geometry on the stress field present in the highly stressed zones (in Italian). Riv. Ital. Saldatura, 1986, 2, 107–116.
31.
LazzarinP.SantaneraA.A parametric analysis of stress concentrations due to longitudinal stiffeners (in Italian). In Proceedings of the 14th AIAS National Conference, Catania, Italy, 1986, pp. 413–427.
32.
AtzoriB.LazzarinP.StaccoE.Effect of spot welded distribution characteristics on the fatigue strength of resistance welded joints. Welding Int., 1988, 2 (8), 707–712.
33.
LazzarinP.AndreazzaR.Stress distribution in L-shaped butt joint: Welded or bonded. Theor. Appl. Fracture Mechanics, 1989, 12, 189–193.
34.
DemelioG.PappalettereC.Sharp V-notches subjected to axial and shear stresses. In Applied Stress Analysis (Eds HydeT. H.OllertonE.), 1990, pp. 711–718 (Elsevier Applied Science, London).
35.
DemelioG.PappalettereC.Stress field near sharp notches. J. Mater. Processing Technology, 1992, 32, 155–160.
36.
BoukharoubaT.TamineT.NuiL.ChehimiC.PluvinageG.The use of notch stress intensity factor as a fatigue crack initiation parameter. Engng Fracture Mechanics, 1995, 52, 503–512.
37.
VerremanY.NieB.Early development of fatigue cracking at manual fillet welds. Fatigue Fracture Engng Mater. Structs, 1996, 19, 669–681.
38.
KiharaS.YoshiA.A strength evaluation method of a sharply notched structure by a new parameter ‘the equivalent stress intensity factor’. Japan Soc. Mech. Engrs Int.J., 1991, 34, 70–75.
39.
LazzarinP.TovoR.A notch stress intensity factor approach to the stress analysis of welds. Fatigue Fracture Engng Mater. Structs, 1998, 21, 1089–1104.
40.
LazzarinP.TovoR.A unified approach to the evaluation of linear elastic stress fields in the neighborhood of cracks and notches. Int. J. Fracture, 1996, 78, 3–19.
41.
AtzoriB.LazzarinP.TovoR.Stress distribution for V-shaped notches under tensile and bending loading. Fatigue Fracture Engng Mater. Structs, 1997, 20, 1083–1092.
42.
GlinkaG.Energy density approach to calculation of inelastic strain-stress near notches and cracks. Engng Fracture Mechanics, 1985, 22, 485–508.
43.
LazzarinP.TovoR.FilippiS.Stress distribution in finite size plates with edge notches. Int. J. Fracture, 1998, 91, 249–262.
44.
LazzarinP.TovoR.MeneghettiG.Fatigue crack initiation and propagation phases near notches in metals with low notch sensitivity. Int. J. Fatigue, 1997, 19, 647–665.
YaoW.XiaK.GuY.On the fatigue notch factor Kf. Int. J. Fatigue, 1995, 17, 245–251.
47.
SähnS.SchaperM.PhamV. B.WurmB.HusertTh.WinschuhE.JaegerG.Damage evolution ahead of sharp notches under cyclic loading. Nucl. Engng Des., 1996, 165, 1–14.
48.
El HaddadM. H.TopperT. H.SmithK. N.Prediction of non-propagating cracks. Engng Fracture Mechanics, 1979, 11, 573–584.
49.
TaylorD.Geometrical effects in fatigue: A unifying theoretical model. Int. J. Fatigue, 1999, 21, 413–420.
50.
NodaN. A.NisitaniH.HaradaS.TakaseY.Fatigue strength of notched specimens having nearly equal sizes of ferrite. Int. J. Fatigue, 1995, 17, 237–244.
51.
Metals Handbook, Vol. 19, Fatigue and Fracture (Ed. LampmanS. R.), 1996 (American Society of Metals, Metals Park, Ohio).
52.
PluvinageG.Rupture and fatigue initiated from notches. Application of notch intensity factor. Rev. Fr. Mecanique, 1997, (1997–1), 53–61.
53.
AtzoriB.LazzarinP.TovoR.From local stress approach to fracture mechanics: A comprehensive evaluation of fatigue strength of welded joints. Fatigue Fracture Engng Mater. Structs, 1999, 22 (5), 369–382.
54.
MaddoxS. J.The Effect of Plate Thickness on the Fatigue Strength of Fillet Welded Joints, 1987 (Abington Publishing, Abington, Cambridge).
RadajD.Design and Analysis of Fatigue Resistant Welded Structures, 1990 (Abington Publishing, Abington, Cambridge).
63.
MaddoxS. J.Scale effect in fatigue of fillet welded aluminium alloy. In Proceedings of the Sixth International Conference onAluminium Weldments (INALCO 95), 1995, Cleveland, Ohio, 1995, pp. 77–93.
64.
HouC. Y.CharngJ. J.Models for the estimation of weldment fatigue crack initiation life. Int. J. Fatigue, 1997, 19, 537–541.
65.
MillerK. J.The three thresholds for fatigue crack propagation. In Fatigue and Fracture Mechanics, Vol. 27, ASTM STP 1296 (Eds PiascikR. S.NewmanJ. C.DowlingM. E.), 1997, pp. 267–286 (American Society for Testing and Materials, Philadelphia, Pennsylvania).
66.
AtzoriB.BlasiG.PappalettereC.Evaluation of fatigue strength of welded structures by local strain measurements. Expl Mechanics, 1985, 25 (2), 129–139.
67.
TovoR.LazzarinP.Relationships between local and structural stress in the evaluation of the weld toe stress distribution. Int. J. Fatigue (in press).
