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Effects of stress invariants and reverse loading on ductile fracture initiation

Voyiadjis, G. Z ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ijsolstr.2012.02.030
  3. Publisher: 2012
  4. Abstract:
  5. Recent research studies on ductile fracture of metals have shown that the ductile fracture initiation is significantly affected by the stress state. In this study, the effects of the stress invariants as well as the effect of the reverse loading on ductile fracture are considered. To estimate the reduction of load carrying capacity and ductile fracture initiation, a scalar damage expression is proposed. This scalar damage is a function of the accumulated plastic strain, the first stress invariant and the Lode angle. To incorporate the effect of the reverse loading, the accumulated plastic strain is divided into the tension and compression components and each component has a different weight coefficient. For evaluating the plastic deformation until fracture initiation, the proposed damage function is coupled with the cyclic plasticity model which is affected by all of the stress invariants and pervious plastic deformation history. For verification and evaluation of this damage-plasticity constitutive equation a series of experimental tests are conducted on high-strength steel, DIN 1.6959. In addition finite element simulations are carried out including the integration of the constitutive equations using the modified return mapping algorithm. The modeling results show good agreement with experimental results
  6. Keywords:
  7. Cyclic plasticity models ; Damage ; Damage functions ; Ductile fracture initiation ; Experimental test ; Finite element simulations ; Fracture initiation ; Integration of the constitutive equations ; Lode angle ; Modeling results ; Research studies ; Return mapping algorithm ; Reverse loading ; Stress invariants ; Stress state ; Tension and compression ; Weight coefficients ; Conformal mapping ; Constitutive equations ; Ductile fracture ; Plastic deformation ; Stress analysis ; Loading
  8. Source: International Journal of Solids and Structures ; Volume 49, Issue 13 , 2012 , Pages 1541-1556 ; 00207683 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0020768312000789