A 3-D model for quantification of fatigue weak-link density and strength distribution in an A713 cast aluminum alloy

Lin Yang, Pei Cai, Zhiqiang Xu, Yan Jin, Chunyong Liang, Fuxing Yin, Tongguang Zhai

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

A quantitative model which took into account the 3-D effects of pores on the local stress/strain fields was developed to quantify the fatigue weak-link density and strength distribution in an A713 Al alloy. In the model, a digital pore structure was first constructed using single-sized pores (15 μm in diameter) that had a total volume fraction same as that of the pores measured experimentally in the alloy. In the surface randomly selected by cross-sectioning through the simulated pore structure, the stress and strain fields around each pore in the surface were quantified using a 3-D finite element model under an applied cyclic stress, and the fatigue crack incubation life at the pore was estimated with a micro-scale Manson-Coffin equation. The quantified rate of fatigue crack initiation at these pores was found to be a Weibull function of the applied stress, which was consistent with the experimental result measured in the alloy. The density and strength distribution of fatigue weak-links could then be derived and used to evaluate the fatigue crack initiation properties of the alloy. By matching to the experimentally measured fatigue weak-links, the minimum critical pore size for fatigue crack initiation was determined to be 11 μm in diameter at the cyclic maximum stress of 100% yield strength of the alloy.

Original languageEnglish
Pages (from-to)185-195
Number of pages11
JournalInternational Journal of Fatigue
Volume96
DOIs
StatePublished - Mar 1 2017

Keywords

  • A713 cast Al alloy
  • Fatigue crack nucleation life
  • Fatigue weak-link density and strength distribution
  • Porosities
  • Prediction of crack incubation life

ASJC Scopus subject areas

  • Modeling and Simulation
  • Materials Science (all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering

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