Application of stress-triaziality dependent fracture criteria for unnotched Charpy specimens
Nonlinear dynamic finite element analysis (FEA) is conducted to simulate the fracture of unnotched Charpy specimens of steel under pendulum impact loading by a dedicated,oversized and nonstandard Bulk Fracture Charpy Machine (BFCM).A phenomenological.stress-triaxiality dependent fracture initiation criterion and a strain softening law for fracture evolution are incorporated in the constitutive relations to predict material failure.The impact energy needed to fracture an unnotched Charpy specimen in a BFCM test can be two orders of magnitude higher than the fracture energy of a Charpy V-notch specimen.FEA results of the BFCM fracture energy compare favorably to the corresponding experimental data.In addition,correlations of fracture energy with specimen geometry,impactor tup width and material type based on the FEA simulations are in excellent agreement with the experimental data.Moreover,the analyses show that the fracture through the thickness of the specimen ranges from shear to ductile modes,demonstrating the importance of applying stress state dependent fracture initiation criteria.Modeling the strain softening behavior is aimed at capturing the residual load carrying capability beyond fracture initiation in a ductile metal.Without the softening branch in a stress-strain curve,the total fracture energy can be significantly under predicted.Applications of the presented failure model in predicting the fracture of other structures are further discussed.
Unnotched Charpy specimen Pendulum impact test Stress-triaziality dependent fracture initiation criterion Fracture evolution Strain softening Finite element analysis Fracture energy Tank car steel
Hailing Yu David Y.Jeong
MacroSys Research and Technology,LLC,55 Broadway,Cambridge,MA 02142 USA U.S.Department of Transportation,Volpe National Transportation Systems Center,55 Broadway,Cambridge,
国际会议
成都
英文
41-51
2009-10-16（万方平台首次上网日期，不代表论文的发表时间）