Affiliations: School of Aeronautics, Northwestern Polytechnical University, Xi'an, Shaanxi, P. R. China
Note: [] Address for correspondence: Prof. Li Yulong, School of Aeronautics, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P. R. China. Tel./Fax: +86 29 8849 4859; E-mail: [email protected].
Abstract: Dynamic fracture toughness (DFT) of a high strength steel, 30CrMnSiA, is determined using a hybrid experimental-numerical method, with a focus on improved understanding of the loading rate effect on DFT under impact loading. The experiments are conducted on the Hopkinson pressure bar (HPB) apparatus with striker velocities ranging from 9.2 to 24.1 m/s to obtain a series of loading rates. Linear-elastic transient finite element analyses are performed to calculate histories of dynamic stress intensity factor (DSIF). The results show that with the increase of striker velocity, the crack tip loading rate increases on the order of 106 MPa m1/2 s−1, while the fracture initiation time and the DFT both reduce. Fracture surface examination is also performed to determine the fracture mode of the material.
Keywords: Dynamic fracture, dynamic stress intensity factor, fracture toughness, Hopkinson pressure bar, high strength steel
