R. Lofstedt, BRITTLENESS, DUCTILITY, AND THE GRIFFITH CRACK, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 55(6), 1997, pp. 6726-6730
The material properties which determine whether a solid will fail by b
rittle fracture or ductile deformation are theoretically investigated
by including the lending-order dissipative term describing plastic flo
w in the equations of elasticity. In particular, this term yields a ti
me scale for the blunting of the elastic crock tip described by Griffi
th. This time scale is compared to the elastic response time of a soli
d to determine whether the solid will sustain the high stresses charac
teristic of a crack tip or will plastically relax the elastic strains.
These dissipative equations of elasticity also describe the ''work-ha
rdened'' state of a solid, where brittle fracture becomes possible in
an originally ductile solid.