caa a22 4500 469123052 CHVBK 20180323133144.0 cr unu---uuuuu 170328e19920901xx s 000 0 eng 10.1007/BF00013006 doi (NATIONALLICENCE)springer-10.1007/BF00013006 Lee Yeong Division of Engineering, Brown University, 02912, Providence, Rhode Island, USA aut Fracture initiation at a crack or notch in a viscoplastic material under high rate loading [Elektronische Daten] [Yeong Lee] The two-dimensional problem of an edge crack in a half space or plate is considered. The body is loaded by a suddenly applied, spatially uniform normal velocity imposed on the plane boundary of the body on one side of the edge crack. Otherwise, the boundary of the body, including the crack faces, is traction free. Both cases of an initially sharp crack tip and a narrow notch with small but nonzero notch root radius are considered. The material is modeled as elastic viscoplastic, including strain hardening, rate sensitivity and thermal softening. The applied loading produces predominantly mode II loading in the crack tip region. Under these conditions it is possible to nucleate an adiabatic shear band at the crack tip as a precursor to a mode II fracture. On the other hand, because of the rate sensitivity of the material and the high rate of loading, it may be possible under certain conditions to generate tensile stresses in the crack tip region sufficiently large to nucleate brittle tensile fracture. The problem is solved numerically by means of the finite element method in order to investigate the competition between these two possible fracture initiation mechanisms. The magnitude of the impact velocity imposed on the edge of the plate and the notch tip acuity have an effect on processes near the crack tip. For given material, the inception of crack growth is determined by the competition between a stress-based brittle fracture condition, associated with rate sensitivity and strain hardening, and a strain based criterion, associated with high strain rate and thermal softening. Kluwer Academic Publishers, 1992 International Journal of Fracture Kluwer Academic Publishers 57/1(1992-09-01), 25-46 0376-9429 57:1<25 1992 57 10704 https://doi.org/10.1007/BF00013006 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00013006 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Lee Yeong Division of Engineering, Brown University, 02912, Providence, Rhode Island, USA aut NATIONALLICENCE 773 0- International Journal of Fracture Kluwer Academic Publishers 57/1(1992-09-01), 25-46 0376-9429 57:1<25 1992 57 10704 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer