Modelling cohesive crack growth using a two-step finite element-scaled boundary finite element coupled method

James Yang, AJ Deeks

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

A two-step method, coupling the finite element method (FEM) and the scaled boundary finite element method (SBFEM), is developed in this paper for modelling cohesive crack growth in quasi-brittle normal-sized structures such as concrete beams. In the first step, the crack trajectory is fully automatically predicted by a recently-developed simple remeshing procedure using the SBFEM based on the linear elastic fracture mechanics theory. In the second step, interfacial finite elements with tension-softening constitutive laws are inserted into the crack path to model gradual energy dissipation in the fracture process zone, while the elastic bulk material is modelled by the SBFEM. The resultant nonlinear equation system is solved by a local arc-length controlled solver. Two concrete beams subjected to mode-I and mixed-mode fracture respectively are modelled to validate the proposed method. The numerical results demonstrate that this two-step SBFEM-FEM coupled method can predict both satisfactory crack trajectories and accurate load-displacement relations with a small number of degrees of freedom, even for crack growth problems with strong snap-back phenomenon. The effects of the tensile strength, the mode-I and mode-II fracture energies on the predicted load-displacement relations are also discussed.
Original languageEnglish
Pages (from-to)333-354
Number of pages22
JournalInternational Journal of Fracture
Volume143
Issue number4
DOIs
Publication statusPublished - Feb 2007
Externally publishedYes

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Keywords

  • Finite element method
  • Scaled boundary finite element method
  • Cohesive crack model
  • Mixed-mode crack propagation
  • Concrete beams
  • Arc-length method

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