A multi-scale material design framework for predicting fracture toughness as function of microstructure
Yan Li (Georgia Tech), David McDowell (Gerogia Tech), Min Zhou ()
Crack initiation and growth: methods, applications, and challenges
Wed 10:45 - 12:15
Barus-Holley 161
Classical fracture mechanics fails to capture the multi-scale nature of fracture. It only based on a continuum description of material domains and fracture behavior. It has been proved that microstructure determines fracture toughness of materials through the activation of different fracture mechanisms. To tailor the fracture resistance through microstructure design, it is important to establish relations between microstructure and fracture toughness. Both a 2D and 3D multiscale computational framework based on CFEM (Cohesive Finite Element Method) is developed to establish relations between microstructure and the fracture toughness of brittle and ductile materials. This framework provides a means for evaluating fracture toughness through explicit simulation of fracture processes involving arbitrary crack paths, including crack tip microcracking and branching. Fracture toughness is computed for heterogeneous microstructures using the J-integral, accounting for the effects of grain/second phase particle size, interfacial properties, texture, and competing fracture mechanisms. Cohesive elements with different traction-separation laws are embedded within different domains to resolve fracture initiation and propagation processes. Parametric studies are performed to study the effect of different cohesive model parameters, such as interface strength and cohesive energy, on the competition between transgranular/intergranular fracture in ductile materials and particle cracking/interfacial debonding in brittle materials. The methodology is useful both for the selection of materials and the design of new materials with tailored properties.