Micromechanisms of Fracture and Fatigue e-bog

Micromechanisms of Fracture and Fatigue provides a detailed insight into the basic micromechanisms of the fracture behaviour of materials, with applications in the engineering industry.Divided into three parts, the first part is devoted to models of deformation and fracture in perfect crystals. Using various atomistic methods, the theoretical strength of solids as a highest reachable strength limit is calculated for a wide range of elements and compounds and compared with experimental data. Connection between the onset of local plasticity in nanoindentation tests and the ideal shear strength is analysed using a multi-scale approach. Moreover, the nature of intrinsic brittleness or ductility of crystal lattices is also demonstrated by the coupling of atomistic and mesoscopic approaches.The second part addresses extrinsic sources of fracture toughness in engineering materials, related to their microstructure and to microstructurally induced crack tortuosity. The results of multilevel modelling, including statistical aspects of microstructure, are used to explain the remarkable phenomena experimentally discovered.In the third part of the book, basic micromechanisms of fatigue propagation of long cracks under uniaxial and multiaxial loading are discussed on the basis of the unified mesoscopic model of crack tip shielding and closure, taking both microstructure and statistical effects into account. Applications to failure analysis are also outlined. In general, an attempt is made to distinguish intrinsic and extrinsic sources of materials resistance to fracture.