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Acquirement of True Stress-strain Curve Using True Fracture Strain Obtained by Tensile Test and FE Analysis

인장시험과 유한요소해석으로 구한 파단 진변형률을 이용한 진응력-진변형률 선도 획득

  • 이경윤 (서강대학교 기계공학과 대학원) ;
  • 김태형 (한국원자력연구원) ;
  • 이형일 (서강대학교 기계공학과)
  • Published : 2009.10.01

Abstract

In this work, we predict a true fracture strain using load-displacement curves from tensile test and finite element analysis (FEA), and suggest a method for acquiring true stress-strain (SS) curves by predicted fracture strain. We first derived the true SS curve up to necking point from load-displacement curve. As the beginning, the posterior necking part of true SS curve is linearly extrapolated with the slope at necking point. The whole SS curve is then adopted for FE simulation of tensile test. The Bridgman factor or suitable plate correction factors are applied to pre and post FEA. In the load-true strain curve from FEA, the true fracture strain is determined as the matching point to test fracture load. The determined true strain is validated by comparing with test fracture strain. Finally, we complete the true SS curve by combining the prior necking part and linear part, the latter of which connects necking and predicted fracture points.

Keywords

Tensile Test;Load-Displacement Curve;True Stress-Strain Curve;Finite Element Model;Bridgman Correction Factor;True Fracture Strain

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