Finite element simulation of delamination growth in composite materials using LS-DYNA

A. M. Elmarakbi, N. Hu, H. Fukunaga

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

In this paper, a modified adaptive cohesive element is presented. The new elements are developed and implemented in LS-DYNA, as a user defined material subroutine (UMAT), to stabilize the finite element simulations of delamination propagation in composite laminates under transverse loads. In this model, a pre-softening zone is proposed ahead of the existing softening zone. In this pre-softening zone, the initial stiffness and the interface strength are gradually decreased. The onset displacement corresponding to the onset damage is not changed in the proposed model. In addition, the critical energy release rate of the materials is kept constant. Moreover, the constitutive equation of the new cohesive model is developed to be dependent on the opening velocity of the displacement jump. The traction based model includes a cohesive zone viscosity parameter (η) to vary the degree of rate dependence and to adjust the maximum traction. The numerical simulation results of DCB in Mode-I is presented to illustrate the validity of the new model. It is shown that the proposed model brings stable simulations, overcoming the numerical instability and can be widely used in quasi-static, dynamic and impact problems.

Original languageEnglish
Pages (from-to)2383-2391
Number of pages9
JournalComposites Science and Technology
Volume69
Issue number14
DOIs
Publication statusPublished - 2009 Nov 1

Keywords

  • B. Cohesive elements
  • B. Delamination growth
  • C. Finite element analysis
  • C. Quasi-static and dynamic analysis

ASJC Scopus subject areas

  • Ceramics and Composites
  • Engineering(all)

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