the cracked brazilian disc (cbd) specimen is widely used in order to determine mode-i/ii and mixed-mode fracture toughness of a rock medium. in this study, the stress intensity factor (sif) on the crack-tip in this specimen is calculated for various geometrical crack conditions using the extended-finite element method (x-fem). this method is based upon the finite element method (fem). in this m...

The initial stage of fretting fatigue crack growth is significantly influenced by tangential force induced by fretting action along the contact surface where a mixed-mode crack growth is involved. Fretting crack behavior of aluminum alloy 2024 was studied, taking into account the problem of contact asperities. Finite element was used for the determination of the stress field near the contact su...

The cracked Brazilian disc (CBD) specimen is widely used in order to determine mode-I/II and mixed-mode fracture toughness of a rock medium. In this study, the stress intensity factor (SIF) on the crack-tip in this specimen is calculated for various geometrical crack conditions using the extended-finite element method (X-FEM). This method is based upon the finite element method (FEM). In this m...

The growth of slant cracks by fretting fatigue of a half plane in contact with a flat rounded pad was studied. The mode I and mode II stress intensity factors for cracks of various lengths and directions were calculated using the semi-analytical method of the distribution of dislocations, and their cumulative effect on the crack growth was investigated using the strain energy density criterion....

Stable ductile crack growth in 3 mm thick AISI 304 stainless steel specimens has been investigated experimentally and numerically. Multi-linear Isotropic Hardening method coupled with the Von-Mises yield criterion was adopted for modeling elasto-plastic behavior of the material. Mode-I CT fracture specimens have been tested to generate experimental load-displacement-crack growth data during sta...

A 2-dimensional, elastic-plastic finite element model has been developed to simulate plasticity induced crack closure in slanted and deflected cracks growing outside the small scale yielding (SSY) regime. The finite element model allows for contact between deformable surfaces to capture the complex contact interaction between the crack faces. Coulomb’s friction law has been used to model fricti...

fracture of mixed mode i/ii in beech wood and its wood polymers has been investigated experimentally in this study. hence, two crack systems of tl and rl were selected in which the crack planes extend along the wood fibers. this investigation has demonstrated that onset of mixed mode cracking can be predicted with a very simple fracture criterion in these crack systems. results indicated that f...

The role of crack-tip shielding in in ̄uencing mixed-mode (mode I‡ II) fatigue-crack growth thresholds for large, through-thickness cracks in a Ti±6Al±4V turbine blade alloy is examined under high-cycle fatigue loading conditions, i.e., at a loading frequency of 1000 Hz in ambient temperature air for load ratios (Kmin=Kmax) of R ˆ 0:1±0.8. Techniques are developed to quantify crack-tip shielding...

The present paper deals with the mixed mode fracture analysis of a weakened orthotropic half-plane with multiple cracks propagation. The orthotropic half-plane contains Volterra type glide and climb edge dislocations. It is assumed that the medium is under in-plane loading conditions. The distributed dislocation technique is used to obtain integral equations for the dynamic problem of multiple ...

There have been few studies to date describing fatigue-crack propagation thresholds under mixed-mode loading conditions in the presence of cracks, that are small as compared to the characteristic microstructural dimensions. To address this need, the variation in mixed-mode, high-cycle fatigue-crack growth thresholds with crack size is reported for a Ti-6Al-4V turbine blade alloy with a fine-gra...