A new asymptotic crack tip model to predict failure processes

A two dimensional finite element asymptotic crack tip model (ABAQUS® code) to simulate crack tip opening displacement (CTOD) and damage in ductile materials has been developed. Pure Mode I is considered with asymptotic displacements applied on the outer boundary of the finite element mesh constructed using plane strain solid and cohesive elements. CTOD profiles and damage variation along cohesive element path are clearly observed. Evolution of CTOD for various ratios of solid/cohesive Young´s Modulus are also presented. The evolution of damage was based on a power law fracture criterion. In an effort to extend isotropic hardening plasticity theory to small scales, the research was focused on room-temperature crack growth in polycrystalline Aluminium alloys. In a future work, stress enhancement will be considered in a framework of cohesive zone modeling and strain gradient plasticity based on the micromechanics of dislocations. An asymptotic crack tip micro structured mesh will be also accounted into the finite element analysis.