Griffith's criterion in Linear elastic fracture mechanics (critical stress intensity factor)


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 suggested that the low fracture strength observed in experiments, as well as the size-dependence of strength, was due to the presence of microscopic flaws in the bulk material. Linear elasticity theory predicts that stress (and hence the strain) at the tip of a sharp flaw in a linear elastic material is infinite. To avoid that problem, Griffith developed a thermodynamic approach to explain the relation that he observed.

Related formulas


CcCritical stress intensity factor( Pa*m1/2) (dimensionless)
EModulus of elasticity ( Young's modulus) (Pa) (dimensionless)
γSurface energy density of the material (j/m2) (dimensionless)