• A numerical investigation of ductile fracture initiation in a high-strength low-alloy steel

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    • Keywords


      Ductile fracture; finite elements; impact loading

    • Abstract


      In this work, static and drop-weight impact experiments, which have been conducted using three-point bend fracture specimens of a high-strength low-alloy steel, are analysed by performing finite-element simulations. The Gurson constitutive model that accounts for the ductile failure mechanisms of microvoid nucleation, growth and coalescence is employed within the framework of a finite deformation plasticity theory. Two populations of second-phase particles are considered, including large inclusions which initiate voids at an early stage and small particles which require large strains to nucleate voids. The most important objective of the work is to assess quantitatively the effects of material inertia, strain rate sensitivity and local adiabatic temperature rise (due to conversion of plastic work into heat) on dynamic ductile crack initiation. This is accomplished by comparing the evolution histories of void volume fraction near the notch tip in the static analysis with the dynamic analyses. The results indicate that increased strain hardening caused by strain rate sensitivity, which becomes important under dynamic loading, plays a benign role in considerably slowing down the void growth rate near the notch tip. This is partially opposed by thermal softening caused by adiabatic heating near the notch tip.

    • Author Affiliations


      R Narasimhan1 S V Kamat1 2

      1. Department of Mechanical Engineering, Indian Institute of Science, Bangalore - 560 012, India
      2. Defence Metallurgical Research Laboratory, Hyderabad - 500 258, India
    • Dates

  • Bulletin of Materials Science | News

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