Structural Engineering and Mechanics

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Out-of-plane ductile failure of notch: Evaluation of Equivalent Material Concept

  • Torabi, A.R. (Fracture Research Laboratory, Faculty of New Sciences and Technologies, University of Tehran) ;
  • Saboori, Behnam (Fatigue and Fracture Research Laboratory, Center of Excellence in Experimental Solid Mechanics and Dynamics, School of Mechanical Engineering, Iran University of Science and Technology) ;
  • Kamjoo, M.R. (Fracture Research Laboratory, Faculty of New Sciences and Technologies, University of Tehran)
  • Received : 2019.07.08
  • Accepted : 2020.03.15
  • Published : 2020.09.10
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Abstract

In the present study, the fracture toughness of U-shaped notches made of aluminum alloy Al7075-T6 under combined tension/out-of-plane shear loading conditions (mixed mode I/III) is studied by theoretical and experimental methods. In the experimental part, U-notched test samples are loaded using a previously developed fixture under mixed mode I/III loading and their load-carrying capacity (LCC) is measured. Then, due to the presence of considerable plasticity in the notch vicinity at crack initiation instance, using the Equivalent Material Concept (EMC) and with the help of the point stress (PS) and mean stress (MS) brittle failure criteria, the LCC of the tested samples is predicted theoretically. The EMC equates a ductile material with a virtual brittle material in order to avoid performing elastic-plastic analysis. Because of the very good match between the EMC-PS and EMC-MS combined criteria with the experimental results, the use of the combination of the criteria with EMC is recommended for designing U-notched aluminum plates in engineering structures. Meanwhile, because of nearly the same accuracy of the two criteria and the simplicity of the PS criterion relations, the use of EMC-PS failure model in design of notched Al7075-T6 components is superior to the EMC-MS criterion.

Keywords

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