3차원 파단 변형률 평면을 이용한 비보강 원판의 펀칭 파단 시뮬레이션
Punching Fracture Simulations of Circular Unstiffened Steel Plates using Three-dimensional Fracture Surface
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참고문헌
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초록
Accidental events such as collisions, groundings, and hydrocarbon explosions in marine structures can cause catastrophic damage. Thus, it is extremely important to predict the extent of such damage, which determines the total amount of oil spills and the residual hull girder strength. Punching fracture tests were conducted by Choung (2009b), where various sizes of indenters and circular unstiffened steel plates with different thicknesses were used to quasi-statically realize damage extents. A three-dimensional fracture strain surface was developed based on a reference (Choung et al., 2015b), where the average stress triaxiality and average normalized Lode angle were used as the parameters governing the fracture of ductile steels. In this study, new numerical analyses were performed using very fine axisymmetric elements in combination with an Abaqus user-subroutine to implement the three-dimensional fracture strain surface. Conventional numerical analyses were also conducted for the tests to identify the best fit fracture strain values by changing the fracture strains. Based on the phenomenon of the average normalized Lode angle starting out positive and then becoming slightly negative, it was inferred that the shear stress primarily dominates in determining the fractures locations, with a partial contribution from the compressive stress. It should be stated that the three-dimensional fracture surface effectively predicted at least the shear stress-dominant fracture behavior of a mild steel.
Abstract
Accidental events such as collisions, groundings, and hydrocarbon explosions in marine structures can cause catastrophic damage. Thus, it is extremely important to predict the extent of such damage, which determines the total amount of oil spills and the residual hull girder strength. Punching fracture tests were conducted by Choung (2009b), where various sizes of indenters and circular unstiffened steel plates with different thicknesses were used to quasi-statically realize damage extents. A three-dimensional fracture strain surface was developed based on a reference (Choung et al., 2015b), where the average stress triaxiality and average normalized Lode angle were used as the parameters governing the fracture of ductile steels. In this study, new numerical analyses were performed using very fine axisymmetric elements in combination with an Abaqus user-subroutine to implement the three-dimensional fracture strain surface. Conventional numerical analyses were also conducted for the tests to identify the best fit fracture strain values by changing the fracture strains. Based on the phenomenon of the average normalized Lode angle starting out positive and then becoming slightly negative, it was inferred that the shear stress primarily dominates in determining the fractures locations, with a partial contribution from the compressive stress. It should be stated that the three-dimensional fracture surface effectively predicted at least the shear stress-dominant fracture behavior of a mild steel.
참고문헌 (26)
- Altair, "HyperWorks 12.0 User Manual", Altair, ~ (2013)
- ASTM E8, "Standard Test Methods of Tension Testing of Metallic Materials", American Society for Testing and Materials, ~ (2004)
- Bao, Y, "On Fracture Locus in the Equivalent Strain and Stress Triaxiality Space", International Journal of Mechanical Sciences, 46(1), pp.81~98 (2004)
- Bao, Y, "Dependence of Ductile Crack Formation in Tensile Tests on Stress Triaxiality, Stress and Strain Ratios", Engineering Fracture Mechanics, 72(4), pp.505~522 (2005)
- Bai, Y, "A New Model of Metal Plasticity and Fracture with Pressure and Lode Dependence", International Journal of Plasticity, 24(6), pp.1071~1096 (2008)
- Basu, S, "On the path-dependence of the fracture locus in ductile materials : Experiments", International Journal of Solids and Structures, 71, pp.79~90 (2015)
- Benzerga, A.A, "On the Path-dependence of the Fracture Locus in Ductile Materialsanalysis", International Journal of Plasticity, 37, pp.157~170 (2012)
- 정준모, "구조물용 강재의 파단기준에 대한 실험 및 이론 연구", 대한조선학회 논문집, 45(2), pp.157~167 (2008), 대한조선학회
- 정준모, "Study on True Stress Correction from Tensile Tests", Journal of Mechanical Science and Technology, 22(6), pp.1039~1051 (2008), 대한기계학회
- Choung, J, "Comparative Studies of Fracture Models for Marine Structural Steels", Ocean Engineering, 36(15), pp.1164~1174 (2009)
- Choung, J, "Micromechanical Damage Modeling and Simulation of Punch Test", Ocean Engineering, 36(15), pp.1158~1163 (2009)
- 정준모, "조선 해양 구조물용 강재의 소성 및 파단 특성 III: 파단 변형률에 관한 실험적 연구", 한국해양공학회지, 25(3), pp.53~66 (2011), 한국해양공학회
- Choung, J, "Estimation of Failure Strain of EH36 High Strength Marine Structural Steel using Average Stress Triaxiality", Marine Structures, 29(1), pp.1~21 (2012)
- 정준모, "저온용 고장력강(EH36)의 평균 응력 삼축비에 따른 파단 변형률 정식화", 한국해양공학회지, 27(2), pp.19~26 (2013), 한국해양공학회
- 정준모, "상용 유한요소코드 사용자-서브루틴을 이용한 저온용 고장력강 (EH36)의 파단 시뮬레이션", 한국해양공학회지, 28(1), pp.34~46 (2014), 한국해양공학회
- Choung, J, "Failure Strain Formulation Via Average Stress Triaxiality of an High Strength Steel for Arctic Structures", Ocean Engineering, 91, pp.218~226 (2014)
- 정준모, "극한지용 고장력강의 평균 응력 삼축비 및 평균 정규 로드 파라메터를 고려한 3차원 파단 변형률 평면 개발: 제1부 이론적 배경과 실험적 연구", 한국해양공학회지, 29(6), pp.445~453 (2015), 한국해양공학회
- 정준모, "극한지용 고장력강의 평균 응력 삼축비 및 평균 정규 로드 파라메터를 고려한 3차원 파단 변형률 평면 개발: 제2부 파단 변형률 평면의 정식화", 한국해양공학회지, 29(6), pp.454~462 (2015), 한국해양공학회
- HSE, "Research report 071: Friction in temporary works" (2003), Health and Safety Executive
- Lehmann, E, "On ductile rupture criteria for structural tear in the case of ship collision and grounding", Proceedings of the Seventh International Symposium on Practical Design of Ships and Mobile Units, pp.141~147 (1998)
- Narr, H, "Comparison of the crashworthiness of various bottom and side structures", Marine Sturctures, 15, pp.443~460 (2002)
- "Norsok Standard N-004, Design of Steel Standards", Standards Norway, ~ (2004)
- Paik, J. K, "On rational design of double Hull Tanker structures against collision", Annual Meeting of SNAME, pp.323~363 (1999)
- Simulia, "Abaqus User Manual", Silumia, ~ (2008)
- Thomas, N, "On fracture loci of ductile materials under non-proportional loading", International Journal of Mechanical sciences, 117, pp.135~151 (2016)
- Yu, H, "Effects of loading path on the fracture loci in a 3D space", Engineering Fracture Mechanics, 151, pp.22~36 (2016)