A new analytical model for the elastic–plastic behaviour of spot welded joints subjected to orthogonal load

Abstract An analytical procedure for the evaluation of the elastic–plastic stiffness behaviour of spot welded joints is presented. The procedure is based on a new model of spot weld region: a circular plate having variable thickness with a central rigid nugget, which is resolved using an original analytical method. The closed-form solution allows to describe the displacement of a rigid nugget when an axial orthogonal load is applied on the plate while plasticity and large deflections are present. The goal is to reach a reliable spot weld region model which can be used as the basis to develop a spot weld element in FE analysis even when plasticity and large deflections are in effect. The procedure is as completely original as no other can be found in the technical literature, and it has been applied to some examples of plates usually employed for spot weld analysis. The analytical results obtained by using the new general relations precisely match those obtained modelling spot weld area by FEA.

[1]  Ning Pan,et al.  Spot welds fatigue life prediction with cyclic strain range , 2002 .

[2]  S. Timoshenko,et al.  THEORY OF PLATES AND SHELLS , 1959 .

[3]  Tau Tyan,et al.  A general failure criterion for spot welds under combined loading conditions , 2003 .

[4]  Andreas Rupp,et al.  Computer Aided Dimensioning of Spot-Welded Automotive Structures , 1995 .

[5]  Tau Tyan,et al.  Failure loads of spot welds under combined opening and shear static loading conditions , 2002 .

[6]  Bertrand Langrand,et al.  Détermination expérimentale du comportement mécanique et de critère de rupture d'assemblages sous chargements mixtes. Application aux rivets et points soudés , 2003 .

[7]  J. Pan,et al.  Mode I stress intensity factor solutions for spot welds in lap-shear specimens , 2007 .

[8]  John E. Mottershead,et al.  Finite element models of spot welds in structural dynamics: review and updating , 2005 .

[9]  R. W. Landgraf,et al.  Advances in Fatigue Lifetime Predictive Techniques , 1992 .

[10]  Soo Won Chae,et al.  An optimal design system for spot welding locations , 2002 .

[11]  On the convergence of the Chien's perturbation method for von Karman plate equations , 1995 .

[12]  Pietro Salvini,et al.  Enforcing of an analytical solution of spot welds into finite element analysis for fatigue-life estimation , 2002 .

[13]  Jacek Skrzypek,et al.  Plasticity and Creep Theory Examples and Problems , 1993 .

[14]  Alain Combescure,et al.  A finite element to simulate the failure of weld points on impact , 2003 .

[15]  Hiroshi Abe,et al.  On Three-Dimensional Elastic-Plastic Stress Analysis of Spot-Welded Joint under Tensile Shear Load , 1991 .

[16]  Pietro Salvini,et al.  A spot weld finite element for structural modelling , 2000 .

[17]  Dieter Radaj.  10 – Structural stress, notch stress and stress intensity approach for assessment of fatigue strength of spot welded joints , 1990 .

[18]  Dung-An Wang,et al.  Stress intensity factors for spot welds and associated kinked cracks in cup specimens , 2005 .

[19]  Wei Chen,et al.  Three-dimensional finite element analysis of the mechanical behavior of spot welds , 2000 .

[20]  Shicheng Zhang,et al.  Fracture mechanics solutions to spot welds , 2001 .

[21]  Sd Sheppard.  Estimation of Fatigue Propagation Life in Resistance Spot Welds , 1993 .

[22]  Geoffrey Turvey,et al.  Elasto-plastic response of uniformly loaded sector plates: full-section yield model predictions and spread of plasticity , 2001 .

[23]  Pietro Salvini,et al.  Extension of the spot weld element to the elasto-plastic case , 2007 .

[24]  Alain Combescure,et al.  Non-linear and failure behaviour of spotwelds: a “global” finite element and experiments in pure and mixed modes I/II , 2004 .

[25]  P.-C. Lin,et al.  Modeling of failure near spot welds in lap-shear specimens based on a plane stress rigid inclusion analysis , 2006 .

[26]  Hongyan Zhang,et al.  Critical specimen sizes for tensile-shear testing of steel sheets , 1999 .

[27]  Shicheng Zhang,et al.  Stress Intensities at Spot Welds , 1997 .

[28]  J. Pan,et al.  Closed-form structural stress and stress intensity factor solutions for spot welds under various types of loading conditions , 2008 .