Fracture Mechanics: Cohesive Zone Modeling

This lecture covers the concept of crack-tip energy dissipation in brittle and ductile materials, introducing the idea of a process zone near the crack tip. It explains the determination of the cohesive zone length using the Dugdale model and the stress intensity caused by tractions along crack faces. The role of small-scale yielding and large-scale bridging in fracture behavior is discussed, along with the length scale hierarchy for small-scale yielding. Analytic and asymptotic solutions for the center crack problem in plane strain are presented, highlighting the dominance of the singular field near the crack tip. Atomistic results showing the stress field ahead of a crack for various crack sizes are also analyzed.