Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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Localized Necking in a Round Tensile Bar for a HCP Material Considering Tension-compression Asymmetry in Plastic Flow

소성 비대칭성을 갖는 HCP 소재의 국부변형 및 네킹해석

  • 윤종헌 (한국기계연구원 부설 재료연구소) ;
  • 이정환 (한국기계연구원 부설 재료연구소)
  • Received : 2012.04.04
  • Accepted : 2012.06.26
  • Published : 2012.08.01
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Abstract

In spite of progress in predicting ductile failure, the development of a macroscopic yield criterion to describe damage evolution in HCP (hexagonal close-packed) materials remains a challenge. HCP materials display strength differential effects (i.e., different behavior in tension versus compression) in their plastic response due to twinning. Cazacu and Stewart(2009) developed an analytical yield criterion for porous material containing randomly distributed spherical voids in an isotropic, incompressible matrix that shows tension-compression asymmetry. The goal of the calculations in this paper is to investigate the effect of the tension-compression asymmetry on necking induced by void nucleation, evolution and consolidation. In order to investigate the effect of the tension-compression asymmetry of the matrix on necking and fracture initiation, three isotropic materials A, B, and C were examined with different ratios of tension-compression asymmetry. The various types of material had BCC, FCC, and HCP crystal structures, respectively. The ratio between tension and compression in plastic flow significantly influences the fracture shape produced by damage propagation as well as affecting the localized neck.

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References

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