| Experimentally observed crack growth histories for aluminum alloy 2519-T87, SA-106C carbon steel, and aluminum alloy 8009 were enforced in growing crack finite element analyses to gain insight into the conditions under which creep-brittle fracture occurs in these materials. The release of finite-element nodes along the crack growth path was accomplished using a new variable time-step, nodal release algorithm. The results indicate an initial transient period of crack growth followed by a quasi-steady state crack growth regime during which K correlates with crack growth rates. Transition of crack growth to quasi-steady state and K controlled conditions is given by a transition time t... |
