نتایج جستجو برای: fracture propagation criteria

تعداد نتایج: 453523  

Journal: :journal of mining and environment 2012
m. behnia k. goshtasbi m. fatehi marji a. golshani

numerical methods such as boundary element and finite element methods are widely used for the stress analysis in solid mechanics. this study presents boundary element method based on the displacement discontinuity formulation to solve general problems of interaction between hydraulic fracturing and discontinuities. the crack tip element and a higher order boundary displacement collocation techn...

2015
Yuliang Su Long Ren Fankun Meng Chen Xu Wendong Wang

Stimulated reservoir volume (SRV) fracturing in tight oil reservoirs often induces complex fracture-network growth, which has a fundamentally different formation mechanism from traditional planar bi-winged fracturing. To reveal the mechanism of fracture network propagation, this paper employs a modified displacement discontinuity method (DDM), mechanical mechanism analysis and initiation and pr...

Most of the existing concrete dams are subjected to cracking. These cracks are caused by various factors such as construction practices, curing, loads and volume change of mass concrete which reduce the efficiency, failure or instability of concrete dams. Using fracture mechanics as a new method to estimate stability and durability of concrete dams is recommended in scientific publications in w...

Journal: :journal of mechanical research and application 2009
mehdi pourmahmoud

modelling of crack propagation by finite element method under mixed mode conditions is of prime importance in fracture mechanics. this paper describes an application of finite element method to the analysis of mixed mode crack growth in linear elastic fracture mechanics. crack growth process is simulated by an incremental crack-extension analysis based on the maximum principal stress criterion,...

A. Golshani K. Goshtasbi M. Behnia M. Fatehi Marji

Numerical methods such as boundary element and finite element methods are widely used for the stress analysis in solid mechanics. This study presents boundary element method based on the displacement discontinuity formulation to solve general problems of interaction between hydraulic fracturing and discontinuities. The crack tip element and a higher order boundary displacement collocation techn...

Journal: :international journal of civil engineering 0
f. dastjerdy civil engineering faculty, k.n.toosi university of technology, no. 1346, vali asr street, mirdamad intersection, tehran, iran o.r. barani civil engineering faculty, k.n.toosi university of technology, no. 1346, vali asr street, mirdamad intersection, tehran, iran f. kalantary civil engineering faculty, k.n.toosi university of technology, no. 1346, vali asr street, mirdamad intersection, tehran, iran

in this paper, a finite element model is developed for the fully hydro-mechanical analysis of hydraulic fracturing in partially saturated porous media. the model is derived from the framework of generalized biot theory. the fracture propagation is governed by a cohesive fracture model. the flow within the fracture zone is modeled by the lubrication equation. the displacement of solid phase, and...

2012
K. Huang A. Ghassemi Harold Vance

Fracture propagation, especially for fractures emanating from inclined wellbores and closed natural fracture often involves Mode I, Mode II, and at times Mode III fracture pattern simultaneously. In this paper a Virtual Multidimensional Internal Bond (VMIB) model is presented to simulate 3D mixedmode fracture propagation. To represent the contact and friction between fracture surfaces, a threed...

2008
J. Heierli A. van Herwijnen P. Gumbsch M. Zaiser

Shear failure models have traditionally dominated the research on slab avalanche initiation in snow science, but evidence has accumulated that they tell us only part of the story. In these models weak snowpack layers are regarded as compounds of zero thickness, but in reality they often consist of ice grain aggregates of finite thickness and high porosity. When such granular aggregates fail, th...

2001
A. Pandolfi C. Yu D. Coker M. Ortiz A. J. Rosakis

We investigate the feasibility of cohesive theories of fracture, in conjunction with the direct simulations of shear-load dominated fracture, to numerically reproduce the inter-sonic crack propagation in unidirectional graphite-epoxy composite plates [1]. The particular configuration contemplated in this study refers to the experiments performed by Coker and Rosakis [2, 3]. The numerical simula...

This paper focuses on some fracture toughness tests performed on the pre-cracked Brazilian specimens of rock-like materials. Also the effect of rock fracture filling on the fracture toughness was considered experimentally.  Fracture toughness is a key parameter for studying the crack propagation and fragmentation processes in rock structures. Fracture mechanics is an applicable tool to improve ...

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