The structural reliability of many brittle materials such as structural ceramics relies on the occurrence of intergranular, as opposed to transgranular, fracture in order to induce toughening by grain bridging. For a constant grain boundary strength and grain boundary toughness, the current work examines the role of grain strength, grain toughness, and grain angle in promoting intergranular fra...

A three-dimensional failure initiation criterion in brittle materials containing a sharp V-notch is presented and validated by experiments. It is based on simultaneous fulfilment of the stress requirement and a finite fracture mechanics energy release rate (ERR) requirement. Since the ERR cannot determine failure initiation direction for dominant mode III loading, the failure initiation orienta...

Understanding the tensile strength properties and damage evolution mechanism in fissured rock is very important to fundamental research engineering design. The effects of flaw dip angle on strength, macroscopic crack propagation failure mode symmetrical Brazilian discs rock-like materials were investigated. A parallel bonding model was proposed examine pre-flawed under splitting load. microscop...

An infinite elastic medium with a planar crack is considered. The crack is subjected to the pressure of fluid injected at a point on the crack surface. Description of the crack growth is based on the lubrication equation (balance of the injected fluid and the crack volume), the equation for crack opening caused by fluid pressure on the crack surface, the Poiseuille equation related local fluid ...

In the study of pre-fabricated single-fissured rock, failure mode, mechanical properties and propagation law rock are affected by length inclination angle fissure. this study, artificially prepared marble-like rocks with different fissure characteristics were used as representatives, using PFC 2D software to establish a uniaxial compression model tests for fissures. The effects lengths angles o...

An assessment of the plasticity-induced crack-closure concept is made, in light of some of the questions that have been raised on the validity of the concept, and the assumptions that have been made concerning crack-tip damage below the crack-opening stress. The impact of using other crack-tip parameters, such as the cyclic crack-tip displacement, to model crack-growth rate behavior was studied...

poor stand establishment of canola (brassica napus l.) under flatland mechanized planting and crust-forming soil is a major problem for farmers in central iran. previous research there showed that irrigated cotton emergence on crust-forming soils under flatland planting can be significantly improved using a double-disk planter with zero-pressure press wheel tires and no crust-breaking. in that ...

Identi fication and sizing of surface breaking cracks using angle beam ultrasonic testing in practical situations quite often becomes a very diffi cult task due to the presence of non-relevant signals caused by geometric refl ectors. The present work introduces effective and systematic approaches to take care of such a diffi culty by use of angle beam ultrasonic testing models that can predict ...

reliability analysis of rock slope stability has received considerable attention in the literature. it has been used as an effective tool to evaluate uncertainty so prevalent in variables. in this research the application of the jointly distributed random variables method for probabilistic analysis and reliability assessment of rock slope stability with plane sliding is investigated. in a recen...