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Methods to Evaluate Stress Triaxiality from the Side Necking Near the Crack Tip

균열선단 부근의 측면함몰로부터 응력삼축성의 결정 방법

  • 김동학 (한국원자력연구소 사용후핵연료기술개발부) ;
  • 강기주 (전남대학교 기계시스템공학부)
  • Published : 2004.07.01

Abstract

Kim et al. suggested an experimental method to determine the Q parameter in situ from the out-of-plane displacement and the in-plane strains on the surface of side necking near the crack tip. In this paper, the procedure to evaluate the stress triaxiality near a crack tip such as the Q parameter is to be polished in the details for simplicity and accuracy. That is, Q and hydrostatic stress are determined only from the out-of-plane displacement, but not using in-plane strain, which is hard to measure. And also, the plastic modulus is determined by an alternative way. Through three-dimensional finite element analyses for a standard CT specimen with 20% side-grooves, the validities of the new procedures are examined in comparison to the old ones. The effect of location where the displacements are measured to determine the stress triaxiality is explored.

Keywords

Out-of-Plane Displacement;Constraint Loss;Side Necking;CT Specimen;Finite Element Method

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