Executive Summary : | Understanding the role of microstructural features such as grains, grain boundaries, voids, etc. on crack propagation and fracture process in materials has always excited mechanicians and material scientists. Studies have shown that the microstructure undergoes evolution under external stimuli and drastically impacts the fracture phenomenon in a material. Specifically, in nanocrystalline materials, processes such as grain rotations at times result in a notch insensitive fracture and could even alter the fracture from intergranular to transgranular nature. Conducting sophisticated experiments by considering in situ microscopy to examine the dependency between microstructure, mechanisms, and fracture has always been challenging, especially when microstructure is undergoing continuous evolution. Several numerical frameworks have been proposed to understand the material fracture, however, mostly limited to the non-evolving microstructural features except few atomistic-level simulations. Hence, proposing a robust and realistic time scale-based computational framework for exploring the role of microstructural features and their evolution during the material fracture is highly desired. Therefore, the present work aims at proposing a novel phase-field fracture framework for an in-depth exploration of crack propagation driven by the material microstructure and its evolution. The proposed phase-field framework incorporates features of both the multi-order parameter-based phase-field model of grain growth as well as the classical phase-field model of fracture. The proposed phase-field framework will incorporate the presence of defects such as voids, and grains, grain boundaries, and their evolution under the presence of boundary curvature induced grain growth and externally applied stress. |