Introduction to fracture mechanics
Lallit Anand, Ken Kamrin, Sanjay Govindjee
Abstract
Abstract This chapter introduces the important topic of fracture of materials and discusses the difference between brittle and ductile mechanisms of fracture; this distinction is discussed at both the local level in a process zone at a crack tip, and at the structural level. A criterion for the brittle fracture of a component which fractures by a locally brittle cleavage mechanism is derived by considering the locally elevated level of tensile stress at a crack tip in relation to the ideal cleavage strength of the material. A derivation of the ideal cleavage strength in terms of the Young’s modulus, the surface energy, and the interatomic lattice spacing of a crystalline material is provided. As a prelude to a discussion of modern fracture mechanics, this fracture criterion is recast in terms of an applied stress intensity factor and a critical stress intensity factor, or fracture toughness, of the material.