FINITE ELEMENT-BASED FATIGUE LIFE PREDICTION OF A LOADCARRYING CRUCIFORM JOINT
DOI:
https://doi.org/10.15282/jmes.8.2015.16.0138Keywords:
Cruciform welded joint; lack of penetration; SIF; fatigue; FRANC 2D/3D.Abstract
The aim of this study is to determine the stress intensity factor (SIF) and fatigue lifecycle of load-carrying 6 mm-thick fillet-welded cruciform joints subjected to fatigue loading conditions by means of finite element analysis (FEA). These joints are typical of automotive structures such as the mid-series rear axle of motor trucks which are sensitive to fatigue loading because of their construction and loading conditions. Finite element software was used to develop various cruciform joint models with varying geometrical dimensions, namely the depth of penetration and weld throat length, and simulation and analysis of the crack propagation were performed with 2D and 3D crack simulation software. The effect of the variations in the weld geometry with an induced crack at the weld root and weld toe on fatigue life was determined from the simulation results. The stress intensity factor values and lifecycles determined by the fracture mechanics approach were compared with the simulation results. It was shown that an increase in the depth of weld penetration and the weld size in isosceles triangles fillet weld shape for crack initiated in the weld root can decrease the stress intensity factor (SIF) and intensify the fatigue lifecycle. It was also found that linear misalignment had no significant effect on the SIF and fatigue life of cracks originating from the weld toe.
References
Motarjemi AK, Kokabi AH, Ziaie AA, Manteghi S, Burdekin FM. Comparison of the stress intensity factor of T and cruciform welded joints with different main and attachment plate thickness. Engineering Fracture Mechanics. 2000;65:55-66.
Al-Mukhtar A, Biermann H, Henkel S, Hübner P. Comparison of the Stress Intensity Factor of Load-Carrying Cruciform Welded Joints with Different Geometries. J of Materi Eng and Perform. 2010;19:802-9.
Barsoum Z, Barsoum I. Residual stress effects on fatigue life of welded structures using LEFM. Engineering Failure Analysis. 2009;16:449-67.
Wei Z, Dong P. Multiaxial fatigue life assessment of welded structures. Engineering Fracture Mechanics. 2010;77:3011-21.
Kamal M, Rahman M, Rahman A. Fatigue life evaluation of suspension knuckle using multi body simulation technique. Journal of Mechanical Engineering and Sciences. 2012;3:291-300.
Kamal M, Rahman MM. Fatigue life estimation models: A state of the art. International Journal of Automotive and Mechanical Engineering. 2014;9:1599-608.
Kamal M, Rahman MM, Sani M. Application of multibody simulation for fatigue life estimation. International Journal of Automotive and Mechanical Engineering. 2013;7:912-23.
Branco R, Antunes FV, Costa JD. A review on 3D-FE adaptive remeshing techniques for crack growth modelling. Engineering Fracture Mechanics. 2015;141:170-95.
Balasubramanian V, Guha B. Influences of welding processes on fatigue life of cruciform joints of pressure vessel grade steels containing LOP defects. Mechanics of Materials. 2000;32:265-76.
Lee CH, Chang KH. Finite element computation of fatigue growth rates for mode I cracks subjected to welding residual stresses. Engineering Fracture Mechanics. 2011;78:2505-20.
Zhao X, Liu Y, Liu Y, Gao Y. Research on fatigue behavior and residual stress of large-scale cruciform welding joint with groove. Materials & Design. 2014;63:593-9.
Balasubramanian V, Guha B. Fatigue life prediction of welded cruciform joints using strain energy density factor approach. Theoretical and Applied Fracture Mechanics. 2000;34:85-92.
Lee CH, Chang KH, Jang GC, Lee CY. Effect of weld geometry on the fatigue life of non-load-carrying fillet welded cruciform joints. Engineering Failure Analysis. 2009;16:849-55.
Smith IFC, Smith RA. Fatigue crack growth in a fillet welded joint. Engineering Fracture Mechanics. 1983;18:861-9.
Frank KH, Fisher JW. Fatigue strength of fillet welded cruciform joints. Journal of the Structural Division. 1979;105:1727-40.
Hobbacher A. Recommendations for fatigue design of welded joints and components. International Institute of Welding; 2007.
Knight J. Some basic fatigue data for various types of fillet welded joints in structural steel: Welding Institute; 1976.
Maddox S. Assessing the significance of flaws in welds subject to fatigue. Welding lournal. 1974;53.
Nykänen T, Li X, Björk T, Marquis G. A parametric fracture mechanics study of welded joints with toe cracks and lack of penetration. Engineering Fracture Mechanics. 2005;72:1580-609.
