조선 해양 구조물용 강재의 소성 및 파단 특성 III: 파단 변형률에 관한 실험적 연구
Plasticity and Fracture Behaviors of Marine Structural Steel, Part III: Experimental Study on Failure Strain
0
조회
0
다운로드
13
인용
0
참고문헌
키워드
초록
This is the third of several companion papers dealing with the derivation of material constants for ductile failure criteria under hydrostatic stress. It was observed that the ultimate engineering stresses and elongations at fracture from tensile tests for round specimens with various notch radii tended to increase and decrease, respectively, because of the stress triaxiality. The engineering stress curves from tests are compared with numerical simulation results, and it is proved that the curves from the two approaches very closely coincide. Failure strains are obtained from the equivalent plastic strain histories from numerical simulations at the time when the experimental engineering stress drops suddenly. After introducing the new concept of average stress triaxiality and accumulated average strain energy, the material constants of the Johnson-Cook failure criterion for critical energies of 100%, 50%, and 15% are presented. The experimental results obtained for EH-36 steel were in relatively good agreement with the 100% critical energy, whereas the literature states that aluminum fits with a 15% critical energy. Therefore,it is expected that a unified failure criterion for critical energy, which is available for most kinds of ductile materials, can be provided according to the used materials.
Abstract
This is the third of several companion papers dealing with the derivation of material constants for ductile failure criteria under hydrostatic stress. It was observed that the ultimate engineering stresses and elongations at fracture from tensile tests for round specimens with various notch radii tended to increase and decrease, respectively, because of the stress triaxiality. The engineering stress curves from tests are compared with numerical simulation results, and it is proved that the curves from the two approaches very closely coincide. Failure strains are obtained from the equivalent plastic strain histories from numerical simulations at the time when the experimental engineering stress drops suddenly. After introducing the new concept of average stress triaxiality and accumulated average strain energy, the material constants of the Johnson-Cook failure criterion for critical energies of 100%, 50%, and 15% are presented. The experimental results obtained for EH-36 steel were in relatively good agreement with the 100% critical energy, whereas the literature states that aluminum fits with a 15% critical energy. Therefore,it is expected that a unified failure criterion for critical energy, which is available for most kinds of ductile materials, can be provided according to the used materials.
참고문헌 (12)
- American Society for Testing and Materials, "E 8 - 04 Standard Test Methods for Tension Testing of Metallic Materials", ~
- Bao, Y, "On Fracture Locus in the Equivalent Strain and Stress Triaxiality space", International Journal of Mechanical Sciences, 46, pp.81~98 (2004)
- Bridgman, P.W, "Studies in large plastic Row and fracture" (1964), Harvard University Press
- 정준모, "조선 해양 구조물용 강재의 소성 및 파단 특성 I: 변형률 경화 및 변형률 속도 경화의 이론적 배경", 한국해양공학회지, 25(2), pp.134~144 (2011), 한국해양공학회
- 정준모, "조선 해양 구조물용 강재의 소성 및 파단 특성 II: 파단의 이론적 배경", 한국해양공학회지, 25(2), pp.92~100 (2011), 한국해양공학회
- Choung, J, "Comparative studies of fracture models for marine structural steels", OCEAN ENGINEERING, 36, pp.1164~1174 (2009), PERGAMON-ELSEVIER SCIENCE LTD
- Choung, J. M., "Study on True Stress Correction from Tensile Tests", Journal of Mechanical Science and Technology, 22(6), pp.1039~1051 (2008), 대한기계학회
- Dey, S, "On the Influence of Fracture Criterion in Projectile Impact of Steel Plates", Computational Materials Science, 38, pp.176~191 (2006)
- Gupta, N.K., "Experimental and Numerical Studies on the Behavior of Thin Aluminum Plates Subjected to Impact by Blunt- and Hemispherical-nosed Projectiles", International Journal of Impact Engineering, 32, pp.1921~1944 (2006)
- Health and Safety Executive, "Offshore Technology Report OTO 2001", 020-Elevated Temperature and High Strain Rate Properties of Offshore Steels, 2001
- Nemat-Nasser, S, "Thermomechanical Response of DH-36 Structural Steel over a Wide Range of Strain Rates and Temperature", Mech. Mat, 35, pp.1023~1047 (2003)
- Teng, X, "Numerical Prediction of Fracture in the Taylor Test", International Journal of Solids and Structures, 42, pp.2929~2948 (2005)