Plasticity and Fracture Behaviors of Marine Structural Steel, Part II: Theoretical Backgrounds of Fracture |
Choung Joon-Mo,Shim Chun-Sik,Kim Kyung-Su |
Dep't of Naval Architecture and Ocean Engineering Inha University,Dep't of Naval Architecture and Marine Engineering Mokpo National University,Dep't of Naval Architecture and Ocean Engineering Inha University |
조선 해양 구조물용 강재의 소성 및 파단 특성 II: 파단의 이론적 배경 |
정준모,심천식,김경수 |
인하대학교 조선해양공학과,국립목포대학교 조선공학과,인하대학교 조선해양공학과 |
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© 2011 The Korean Society of Ocean Engineers
Open access / Under a Creative Commons License
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Keywords:
Stress triaxiality, Fracture strain(Failure strain), Shear failure, Porosity, Principal strain, Damage |
핵심용어:
응력 삼축비, 파단 변형률, 전단 파단, 기공률, 주변형률, 손상 |
Abstract |
The main goal of this paper is to provide the theoretical backgroundfor the fracture phenomena in marine structural steels. In this paper, various fracture criteria are theoretically investigated: shear failure criteria with constant failure strain and stress triaxiality-dependent failure strain (piecewise failure and Johnson-Cook criteria), forming limit curve failure criterion, micromechanical porosity failure criterion, and continuum damage mechanics failure criterion. It is obvious that stress triaxiality is a very important index to determine the failure phenomenon for ductile materials. Assuming a piecewise failure strain curve as a function of stress triaxiality, the numerical results coincide well with the test results for smooth and notched specimens, where low and high stress triaxialities are observed. Therefore, it is proved that a failure criterion with reliable material constants presents a plastic deformation process, as well as fracture initiation and evolution. |
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