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...

A model is provided for crack problem in a functionally graded semi-infinite plate under an anti-plane load. The characteristic of material behavior is assumed to change in a linear manner along the plate length. Also the embedded crack is placed in the direction of the material change. The problem is solved using two separate techniques. Primary, by applying Laplace and Fourier transformation,...

In this paper, the present investigation has been conducted keeping in mind some of the problems concerning the crack propagation direction and growth under constant loading in an inclined crack geometry. The present studies mainly focused on the development and modifications in the crack growth criterion to account the biaxial, shear loading and number of stress terms. Existing criteria for th...

An extensive experimental study of indentation and crack arrest statistics is presented for four different brittle materials (alumina, silicon carbide, silicon nitride, glass). Evidence is given that the crack length statistics is described by a universal (i.e., material independent) distribution. The latter directly derives from results obtained when modeling crack propagation as a depinning p...

In the short crack regime of the fatigue process, grain boundaries in steels are barriers against crack growth. In this paper, we use: (1) a method involving crack density; and (2) a method of dimensional analysis, to evaluate the effects of grain size and grain-boundary resistance on short crack behaviour and fatigue life. The results show that the fatigue life increases with a decrease in gra...

An observed minimum in the critical crack initiation load at Poisson’s ratio (ν) of 0.21–0.22 in Na2O–TiO2–SiO2 glasses was investigated. Vickers indentation was used to examine hardness and average cracking length, fracture toughness was measured through the single-edge pre-cracked beam method, and volumes of densification and shear flow around indents were measured using atomic force microsco...

Linear eigenvalue analysis of cracked cylindrical shells under combined internal pressure and axial compression is carried out to study the effect of crack type, size and orientation on the buckling behavior of cylindrical thin shells. Two types of crack are considered; through crack and thumbnail crack. Our calculations indicate that depending on the crack type, length, orientation and the int...

The effects of loading conditions, specimen size and metal particle size on the crack growth resistance curve (R-curve) and residual strength of a ceramic-metal functionally graded material (FGM) are studied based on the crack-bridging concept. It is found that the FGM exhibits strong R-curve behavior when a crack grows from the ceramic-rich region toward the metal-rich region and the residual ...

In this study, the vibration of cracked plates is investigated using the differential quadrature method and experimental modal analysis. The crack, which is assumed to be open, is modeled by the extended rotational spring. With its finite length, the crack divides the plate into six segments. Then, the differential quadrature is applied to the governing differential equations of motion and the ...