Quantification of the Influence of Residual Stresses on Fatigue Strength of Al-Alloy Welded Joints by Means of the Local Strain Energy Density Approach

Depending on boundary conditions, welding parameters and plate thickness, high residual tresses may arise near the weld toe of a welded joint. Compressive or tensile residual stresses significantly influence the fatigue strength of the joints in the high-cycle regime. If the weld toe is modelled as a sharp, zero-radius V-shaped notch, the residual stress fields can be expressed in terms of residual notch stress intensity factors (R–NSIFs) calculated in the elastic or elastic-plastic fields. The possibility to quantify the intensity of the residual singular stress field by means of the R–NSIFs allows the designer to estimate the influence of residual stresses on the fatigue life of welded joints. In this work, the influence of residual stresses on the fatigue resistance of Al-alloy butt-welded joints is estimated by using the local stain energy density approach. Values predicted by the proposed method show a good agreement with experimental data taken from literature.

[1]  Bernard Gross,et al.  Plane elastostatic analysis of V-notched plates , 1972 .

[2]  Yuh J. Chao,et al.  Effects of temperature-dependent material properties on welding simulation , 2002 .

[3]  Filippo Berto,et al.  A comparison among some recent energy- and stress-based criteria for the fracture assessment of sharp V-notched components under Mode I loading , 2014 .

[4]  Filippo Berto,et al.  Three‐dimensional stress fields due to notches in plates under linear elastic and elastic–plastic conditions , 2015 .

[5]  Jani Romanoff,et al.  Fatigue strength assessment of laser stake‐welded web‐core steel sandwich panels , 2013 .

[6]  Paolo Ferro,et al.  The local strain energy density approach applied to pre-stressed components subjected to cyclic load , 2014 .

[7]  Paolo Lazzarin,et al.  A NOTCH INTENSITY FACTOR APPROACH TO THE STRESS ANALYSIS OF WELDS , 1998 .

[8]  Filippo Berto,et al.  Recent developments in brittle and quasi-brittle failure assessment of engineering materials by means of local approaches , 2014 .

[9]  A. Barroso,et al.  Prediction of welding residual stresses and displacements by simplified models. Experimental validation , 2010 .

[10]  Franco Bonollo,et al.  The influence of phase transformations on residual stresses induced by the welding process—3D and 2D numerical models , 2006 .

[11]  Paolo Lazzarin,et al.  From a local stress approach to fracture mechanics: a comprehensive evaluation of the fatigue strength of welded joints , 1999 .

[12]  Guy Pluvinage,et al.  The use of notch stress intensity factor as a fatigue crack initiation parameter , 1995 .

[13]  P. Ferro,et al.  Influence of phase transformations on the asymptotic residual stress distribution arising near a sharp V-notch tip , 2012 .

[14]  Filippo Berto,et al.  A review of the volume-based strain energy density approach applied to V-notches and welded structures , 2009 .

[15]  Filippo Berto,et al.  Fatigue strength of structural components under multi-axial loading in terms of local energy density averaged on a control volume , 2011 .

[16]  R. Ambriz,et al.  Mechanical Behavior of Precipitation Hardened Aluminum Alloys Welds , 2014 .

[17]  M. Williams,et al.  Stress Singularities Resulting From Various Boundary Conditions in Angular Corners of Plates in Extension , 1952 .

[18]  Filippo Berto,et al.  Fatigue strength of severely notched specimens made of Ti–6Al–4V under multiaxial loading , 2015 .

[19]  Gaoyang Mi,et al.  A thermal–metallurgical model of laser beam welding simulation for carbon steels , 2015 .

[20]  Franco Bonollo,et al.  Methodologies and experimental validations of welding process numerical simulation , 2010 .

[21]  Nicola Petrone,et al.  Asymptotic thermal and residual stress distributions due to transient thermal loads , 2009 .

[22]  Paolo Lazzarin,et al.  Notch stress intensity factors and fatigue strength of aluminium and steel welded joints , 2001 .

[23]  Timothy Russell Gurney,et al.  Fatigue of Welded Structures , 1980 .

[24]  Yves Verreman,et al.  Early development of fatigue cracking at manual fillet welds , 1996 .

[25]  Paolo Lazzarin,et al.  Fatigue strength of steel and aluminium welded joints based on generalised stress intensity factors and local strain energy values , 2005 .

[26]  Jf Throop,et al.  Residual Stress Effects in Fatigue , 1982 .

[27]  Alberto Cardona,et al.  Finite element modeling of welding processes , 2011 .

[28]  Hidekazu Murakawa,et al.  Influence of thermo-mechanical material properties of different steel grades on welding residual stresses and angular distortion , 2015 .

[29]  Vigilio Fontanari,et al.  Influence of post weld treatments on the fatigue behaviour of Al-alloy welded joints , 1998 .

[30]  Filippo Berto,et al.  High temperature fatigue tests of un-notched and notched specimens made of 40CrMoV13.9 steel , 2014 .

[31]  Shahram Sarkani,et al.  An efficient approach for computing residual stresses in welded joints , 2000 .

[32]  L. Pook.  A 50‐year retrospective review of three‐dimensional effects at cracks and sharp notches , 2013 .

[33]  D. Radaj,et al.  State‐of‐the‐art review on extended stress intensity factor concepts , 2014 .

[34]  Filippo Berto,et al.  Generalized stress intensity factors due to steady and transient thermal loads with applications to welded joints , 2006 .

[35]  Paolo Lazzarin,et al.  A finite-volume-energy based approach to predict the static and fatigue behavior of components with sharp V-shaped notches , 2001 .

[36]  T. Teng,et al.  Analysis of residual stresses and distortions in T-joint fillet welds , 2001 .

[37]  Filippo Berto,et al.  Fatigue strength of notched specimens made of 40CrMoV13.9 under multiaxial loading , 2014 .

[38]  Øystein Grong,et al.  Metallurgical modelling of welding , 1994 .

[39]  D H B Mok,et al.  Finite Element Study of Residual Stresses in a plate T-Joint Fatigue Specimen , 1990 .

[40]  J. Goldak,et al.  A new finite element model for welding heat sources , 1984 .