Fracture mechanics

Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture.Griffith's work was largely ignored by the engineering community until the early 1950s. The reasons for this appear to be (a) in the actual structural materials the level of energy needed to cause fracture is orders of magnitude higher than the corresponding surface energy, and (b) in structural materials there are always some inelastic deformations around the crack front that would make the assumption of linear elastic medium with infinite stresses at the crack tip highly unrealistic. { K I K I I } = ( 2 π ) 1 / 2 ∫ − ∞ l [ { T y − λ ′ ( l ) T x T x + λ ′ ( l ) T y } 1 ( l − x ) 1 / 2 + { T x T y } [ λ ( l ) − λ ( x ) − λ ′ ( l ) ( l − x ) ] 2 ( l − x ) 3 / 2 ] {displaystyle {egin{Bmatrix}K_{I}\K_{II}end{Bmatrix}}=left({frac {2}{pi }} ight)^{1/2}int _{-infty }^{l}left}{2(l-x)^{3/2}}} ight]} Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture. In modern materials science, fracture mechanics is an important tool used to improve the performance of mechanical components. It applies the physics of stress and strain behavior of materials, in particular the theories of elasticity and plasticity, to the microscopic crystallographic defects found in real materials in order to predict the macroscopic mechanical behavior of those bodies. Fractography is widely used with fracture mechanics to understand the causes of failures and also verify the theoretical failure predictions with real life failures. The prediction of crack growth is at the heart of the damage tolerance mechanical design discipline.