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Vol.43, No.11, 754 ~ 759, 2005
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| Title |
| Special Edition : Symposium on Mechanical Behavior of Materials(1) ; Correction of Constraint Loss on Fracture Toughness Test Specimen in Ductile-to-Brittle Transition Region Using Finite Element Analysis |
| 김만원 M. W. Kim , 양원존 W. J. Yang , 김민철 M. C. Kim , 이봉상 B. S. Lee , 홍준화 J. H. Hong |
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| Abstract |
| Structural integrity assessment or regulatory procedures of cracked components are based on the use of fracture toughness parameters. ASTM E1921 presents a direct method to obtain the fracture toughness, the Master Curve, using small specimens in the transition range. Fracture toughness can be affected by the size and thickness of specimen in the transition range. These effects can be explained by the plastic constraint loss and the statistical weakest-link theory in general. ASTM E1921 presents a statistical model to correct these effects. In this work, a numerical procedure based on micro-mechanical model is described in detail and applied to adjust the plastic constraint loss in 1/3PCVN and PCVN specimens. Plastic constraint loss can be effectively adjusted by comparing the J-integral values calculated in the 2-D finite element analysis for small-scale yielding and 3-D finite element analysis for large scale yielding in the same size of crack tip plastic area. After KJC is adjusted by using the corrected J-values, the statistical size effect are also corrected according to the standard ASTM E 1921 procedure. The results showed a good correction effect for the small size specimens. |
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| Key Words |
| Fracture toughness, Ductile-to-brittle transition, Finite element analysis, Master curve, Reference temperature T0, PCVN, ASTM E1921 |
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