COMPUTATIONAL ANALYSIS OF CRACK GROWTH IN DUCTILE MATERIALS

Resumo

Rupture in metals can occur by cleavage, where all process is controlled by stresses, or by a
combination of critical stresses and strains in a process known as ductile fracture. The Linear Elastic
Fracture Mechanics, widely used in engineering practice, is in general based on the assumption that
the first process prevails, which occurs only under certain conditions. Consideration of the second
fracture process is not so well disseminated. In this work, two methodologies are considered to take
into account the transition cleavage/ductile. One is based on the Tvergaard-Hutchinson's trapezoidal
cohesive model and the other is based on the Gurson's ductile damage model. The two models are
considerably different and in this work, initially, the relationships between the two models are
established. Then, the conditions for a transition from cleavage to ductile fracture are determined and
discussed. Results are presented based on crack growth resistance curves obtained for different
material parameters. A simple numerical model in mode I rupture is considered.