Effect of Inclusion Distribution on Ductile Fracture Toughness and Fracture Surface Roughness
Ankit Srivastava (University of North Texas), Shmuel Osovski (University of North Texas), Laurent Ponson (Institut Jean Le Rond d'Alembert Université Pierre et Marie Curie), Viggo Tvergaard (Technical University of Denmark), Elisabeth Bouchaud (CEA-Saclay and ESPCI Paris Tech), Alan Needleman (University of North Texas)
Crack initiation and growth: methods, applications, and challenges
Wed 9:00 - 10:30
Barus-Holley 161
A predictive model of fracture underlies the development of more fracture resistant materials. The relation between the crack growth resistance and fracture surface morphology remains to be clarified for ductile solids. The morphology of fracture surfaces reveals how microstructural features affect crack growth. Recent work suggests that analyses based on a damage constitutive relation for ductile fracture provide a promising tool for exploring this relation. Here, finite element, finite deformation calculations are carried out using a constitutive framework for progressively cavitating ductile solids. The matrix material is modeled as an isotropic hardening viscoplastic solid. The large inclusions, which nucleate voids at an early stage, are modeled as a three dimensional distribution of “islands” of the amplitude of the void nucleation function. Their size and spacing introduce a microstructurally based characteristic length into the formulation. The smaller second-phase particles, which require large strains for void nucleation, are uniformly distributed, and so do not introduce any physically based length scale. The calculations are carried out for small scale yielding conditions under remote Mode I loading. Results are presented for the fracture toughness and the statistics on the fracture surface roughness for various inclusion densities and distributions. The extent to which the fracture surface morphology and the crack growth resistance can be related will be discussed.