Mechanics of Ductile Fracture.

The phenomenon of ductile fracture in plate specimens is described by a finite element stress analysis coupled with the strain energy density fracture criterion. The last ligament of failure tends to curve developing a cup-and-cone type of fracture in tensile bars and sheer lips in plate specimens. Three-dimensional crack growth profiles are developed by assuming that materials tend to break along the path of minimum strain energy density whose critical value is characteristic of the material and has been measured experimentally for both elastic and plastic materials. The results are encouraging in that ductile fracture behavior can be modeled by holding the strain energy density constant. Hence, allowable load and net section size can be predicted for specimens that deform in the plastic range. Author