The available stock of the material is very often insuffi cient to machine conventional specimens and conduct tests according to ASTM Standards. Specially, it is diffi cult to meet the specimen size requirements, such as thickness or planar width, and estimate fracture toughness of high strength materials by means of KIc, JIc, or CTOD. A Local Approach to Fracture is an alternative methodology ...

The paper presents a numerical model to study the transition of brittle materials from cracked solid granular medium under impact loading. addresses competitive crack coalescence in regime and provides insight into onset comminution initial conditions for subsequent flow. Crack statistics obtained flaws using wing growth-based damage have been used discretely elliptical cracks three dimensions....

The dynamic anisotropy and failure mechanism of shales are greatly affected by bedding surfaces. To reveal the influence beddings on anisotropic characteristics under impact, Brazilian splitting tests were conducted split Hopkinson pressure bar system. fracturing process monitored high-speed camera. Meanwhile, to understand crack initiation propagation mechanism, stress buildup, shadow transfer...

condensing flows in nozzles and fixed blades of steam turbine have always been the subject of many studies.in such flows, existence of liquid phase in vapor changes the nature of the flow. the major of changes are due to four main mechanisms included nucleation, droplet growth, coalescence and breakage of droplets. in this paper,the effects of coalescence process between droplets have been inve...

A quasi-continuum (QC) method based on the embedded atom method (EAM) potential was employed to investigate the fatigue crack growth and expansion characteristics of single-crystal Fe and Ni under cyclic loading modes I and II. In particular, the crack growth and expansion characteristics of Fe and Ni under cyclic loading were evaluated in terms of atomic stress fields and force–distance curves...

Abstract In the construction procedure of infrastructure, excavation disturbance significantly changes initial stress state rocks in deep geotechnical engineering, and a rock burst would occur accompanied by ejection block. present study, true triaxial unloading test its corresponding numerical analysis based on three-dimensional particle flow code (PFC3D) are conducted granite specimens to acq...

In this article, we developed a thermodynamically consistent non-local microcracking model for quasi-brittle materials with application to concrete. The is implemented using novel graph-based finite element analysis (GraFEA) approach that allows (i) the probabilistic modeling of growth and coalescence microcracks, (ii) crack closure kinematics-based approach, (iii) rate effects on microcracking...

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...