Issue 9

An. Carpinteri et alii, Frattura ed Integrità Strutturale, 9 (2009) 46 – 54; DOI: 10.3221/IGF-ESIS.09.05 53 Reference No. specimens Scatter band 2 % Scatter band 3 % Archer [19] 18 94 100 Siljander et al. [20] 30 77 97 Bäckström et al. [21] 21 24 29 Sonsino et al. [11] 43 65 81 Table 1 : Percentage of the results included into the scatter bands with coefficients 2 and 3, for each experimental data set analysed [11, 19–21]. C ONCLUSIONS n the present paper, the criterion proposed by Carpinteri and Spagnoli for both smooth and notched structural components is extended to the fatigue assessment of welded joints under in-phase or out-of-phase loadings. The averaged principal stress axes, determined through the weight function method, are used to predict the orientation of the critical plane where to perform the fatigue failure assessment. Then a fatigue failure criterion based on a nonlinear combination of an equivalent normal stress amplitude and the shear stress amplitude acting on the critical plane is employed to carry out such an assessment. The criterion proposed is applied to relevant experimental results, available in the literature, related to welded joints subjected to bending (or tension), torsion, in-phase or out-of-phase combined bending (or tension) and torsion. It can be remarked that, in most of the cases here examined, the fatigue life predictions of the present criterion fall within a scatter band of coefficient 3. A CKNOWLEDGEMENTS he authors gratefully acknowledge the research support for this work provided by the Italian Ministry for University and Technological and Scientific Research (MIUR). R EFERENCES [1] D. Radaj, (1990). Design and analysis of fatigue-resistant welded structures. Abington Publishing, Cambridge, UK. [2] European Committee for Standardization. Eurocode 3. Design of steel structures. Part 1-1: General rules and rules for buildings. ENV 1993-1 (1992). [3] E. Haibach, B. Atzori, Applied to Welded Joints in AlMg5. Society of Environmental Engineers Fatigue Group, Mid- year Conference (1975). [4] T.R. Gurney, Fatigue of Welded Structures. Cambridge University Press, Cambridge, UK (1979). [5] P. Lazzarin, R. Tovo, Fatigue Fract. Engng. Mater. Struct., 21, (1998) 1089. [6] P. Lazzarin, C.M.Sonsino, R.Zambardi, Fatigue Fract. Engng. Mater. Struct., 27 (2004) 127. [7] D. Radaj, Z. Zheng, W. Möhrmann, Engng Fract. Mechs ., 37 (1990) 933. [8] D. Taylor, Engng Failure Analysis, 3 (1996) 129. [9] C.M. Sonsino, D. Radaj, U. Brandt, H.P. Lehrke, Int. J. Fatigue, 21 (1999) 985. [10] D. Taylor, N. Barrett, G. Lucano, Int. J. Fatigue, 24 (2002) 509. [11] C.M. Sonsino, M. Kueppers, Fatigue Fract. Engng. Mater. Struct., 24 (2001) 309. [12] A. Carpinteri, R. Brighenti, E. Macha, A. Spagnoli, Int. J. Fatigue, 21 (1999) 83. [13] A. Carpinteri, R. Brighenti, E. Macha, A. Spagnoli, Int. J. Fatigue, 21 (1999)89. [14] A. Carpinteri, R. Brighenti, A. Spagnoli, Fatigue Fract. Engng. Mater. Struct. 23 (2000) 355. [15] A. Carpinteri, A. Spagnoli, Int. J. Fatigue, 23 (2001) 135. [16] A. Carpinteri, A. Spagnoli, S. Vantadori, Fatigue Fract. Engng. Mater. Struct., 26 (2003) 515. [17] A. Carpinteri, A. Spagnoli, S. Vantadori, D. Viappiani, Engng Fract. Mechs ., 75 (2008) 1864. [18] A.Carpinteri, A. Spagnoli, S. Vantadori, Int. J. Fatigue, 31 (2009) 188. I T