Abstract
The fracture toughness in an elastic-plastic material joined by a laser weld is analyzed for steady-state crack growth along the weld. The analysis is performed for laser welds in steel. Laser welding gives high mismatch between the yield stress within the weld and that in the base material, due to the fast thermic cycle that the material undergoes in welding. The material is described by J 2-flow theory, and the analysis is performed using a special numerical algorithm, in which the finite element mesh remains fixed relative to the tip of the growing crack, so that the material moves through the mesh. Fracture is modelled by using a cohesive zone criterion in front of the crack tip along the fracture zone. It is found that in general a thinner laser weld gives a higher interface toughness. Furthermore, it is shown that the preferred path of the crack is in the base material slightly outside the weld; a phenomenon also observed in experiments.
Similar content being viewed by others
References
Barenblatt, G.I. (1962). Advances in Applied Mechanics, Vol.7, Academic Press, London, chapter Mathematical Theory of Equilibrium Cracks, pp. 56–129.
Barsom, J. and Rolfe, S. (1957). Fracture and Fatigue Control in Structures: Application of Fracture Mechanics, 2nd ed. Prentice-Hall, NJ, p. 265.
Dean, R.H. and Hutchinson, J.W. (1980). Quasi-static steady crack growth in small-scale yielding', American Society for Testing and Materials, Special Technical Publication 700, pp. 383–405.
Kirk, M.T. and Dodds, R.H. (1993). The influence of weld strength mismatch on crack-tip constraint in single edge notch bend specimens. International Journal of Fracture 63, 297–316.
Kristensen, J.K. and Borggren, K. (1998). Small and large scale testing of C02-laser welded structural steels. In: 6th International Conference on Welding and Melting by Electron and Laser Beams.
Lin, G., Meng, X.-G., Cornec, A. and Schwalbe, K.-H. (1999). The effect of strength mismatch on mechanical performance of weld joints. International Journal of Fracture 96, 37–54. Analysis of steady-state ductile crack growth along a laser weld 69
Needleman, A. and Tvergaard, T. (1999). A micromechanical analysis of the ductile-brittle transition at a weld. Engineering Fracture Mechanics 62, 317–338.
Rice, J.R. and Sorenson, E.P. (1978). Continuing crack-tip deformation and fracture for plane-strain crack growth in elastic-plastic solids. Journal of the Mechanics and Physics of Solids 26, 163–186.
Thaulow, C., Hauge, M., Zhang, Z., Ranestad, O. and Fattorini, F. (1999). On the interrelationship between fracture toughness and material mismatch for cracks located at the fusion line of weldments. Engineering Fracture Mechanics 64, 367–382.
Tvergaard, V. and Hutchinson, J.W. (1992). The relation between crack growth resistance and fracture process parameters in elastic-plastic solids. Journal of the Mechanics and Physics of Solids 40, 1377–1397.
Tvergaard, V. and Hutchinson, J.W. (1993). The influence of plasticity on mixed mode interface toughness. Journal of the Mechanics and Physics of Solids 41, 1119–1135.
Varias, A.G. and Shih, C.F. (1993). Quasi-static crack advance under a range of constraints steady fields based on characteristic length. Journal of the Mechanics and Physics of Solids 41, 835–861.
Wei, Y. and Hutchinson, J.W. (1996). Mixed mode interface toughness of metal/ceramic joints. In: Material Research Society Symposium Proceedings, Vol. 409, pp. 163–170.
Wei, Y. and Hutchinson, J.W. (1997). Nonlinear delamination mechanics for thin films. Journal of the Mechanics and Physics of Solids 45, 1137–1159.
Wei, Y. and Hutchinson, J.W. (1999). Models of interface separation accompanied by plastic dissipation at multiple scales. International Journal of Fracture 95, 1–17.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Niordson, C.F. Analysis of steady-state ductile crack growth along a laser weld. International Journal of Fracture 111, 53–69 (2001). https://doi.org/10.1023/A:1010951331590
Issue Date:
DOI: https://doi.org/10.1023/A:1010951331590