Mixed mode stress intensity factors for elliptical subsurface cracks in an elastic half-space subjected to a uniform normal loading

作者：Ghajar R^*; Alizadeh K J

来源：Fatigue and Fracture of Engineering Materials and Structures, 2013, 36(11): 1199-1208.

DOI：10.1111/ffe.12073

• coupling of the modes
• elliptical subsurface crack
• mixed mode
• stress intensity factors

An elliptical subsurface crack under normal loading may experience mixed fracture modes due to the non-symmetrical geometry. This paper investigates the coupling of the modes of elliptical subsurface cracks subjected to a uniform normal loading. First, a three-dimensional finite element model of a crack in an infinite space has been developed and validated. Then, by moving the crack close to surface, mixed mode SIFs have been calculated for a wide range of elliptical subsurface cracks under uniform normal loading. Cracks with aspect ratios of 0.2-1.0 and ratios of crack depth to crack length from 0.05 to infinity have been investigated through 50 finite element analyses. In this range, K-II/K-I and K-III/K-I ratios increase up to 68.9% and 9.4%, respectively. Three equations for mode I, II and III SIFs have been obtained by fitting to the finite element results. These equations can be used efficiently as reference SIFs for extracting the weight functions.

• 出版日期2013-11