Crack initiation observation and local stress analysis in shear fracture tests of ultra-high strength steels

10th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes

Ma, Ninshu^1 ; Takada, Kenji^2 ; Sugimoto, Nao^2

JSOL Corporation, 2-2-4, Tosabori, Nishiku, Osaka

550-0001, Japan^1

Honda RandD Co. Ltd., 4630, Shimo-Takanezawa, Hagamachi, Haga-gun, Tochigi-ken

321-3393, Japan^2

关键词: Fracture surfaces;    Local stress analysis;    Plane strain state;    Propagation direction;    Shear fracture;    Stress triaxiality;    Ultra high strength steel;    Uniaxial tensile;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/734/3/032049/pdf
DOI  :  10.1088/1742-6596/734/3/032049

来源: IOP

【 摘 要 】

To investigate the local strain and stress at the crack initiation position in shear fracture test pieces of ultra-high strength steels, a butterfly shear fracture specimen was employed. The crack initiation position and propagation direction were observed during shear fracture tests by high speed cameras and investigated through analysing the fracture surface by scanning electron microscope. Further, the finite element method was employed and the stress-triaxiality at the crack initiation position was investigated. It can be obtained that the crack initiated at the position where the stress state is close to uniaxial tensile state or plane strain state more than pure shear stress state.