نتایج جستجو برای: crack initiation angle

تعداد نتایج: 247747  

2015
Huayang Zhang Jinxiang Liu Zhengxing Zuo

Residual compressive stress can improve fretting fatigue strength. In this paper, the effects of residual stress on fretting fatigue of Al 2024-T351 alloy specimens are studied using a numerical approach. The extended finite element method combined with the cyclic cohesive zone model is adopted to model fretting fatigue crack growth behavior. It is shown that residual stress changes the frettin...

Journal: :international journal of civil engineering 0
z.y. wang department of civil engineering & mechanics, college of architecture and environment, sichuan university, chengdu, pr china,610065 q.y. wang department of civil engineering & mechanics, college of architecture and environment, sichuan university, chengdu, pr china,610065

this paper presents a finite element analysis and its related experimental test of corrugated steel web beams subjected to fatigue loading. a particular focus in this study was set on the fatigue failure arising from the web-to-flange welded joint of the corrugated steel web beam. a detailed three-dimensional finite element model which explicitly includes the geometry of the web-to-flange welds...

2002
T. L. Becker R. O. Ritchie

Analysis has been performed on fracture initiation near a crack in a brittle material with strength described by Weibull statistics. This nonlocal fracture model allows for a direct correlation between near crack-tip stresses and failure. Predictions are made for both the toughness and average fracture initiation angle of a crack under mixed-mode loading. This is pertinent for composites and is...

2004
C. L. Chow X. F. Chen

An anisotropic model of damage mechanics for ductile fracture incorporating the endochronic theory of plasticity is presented in order to take into account material deterioration during plastic deformation. An alternative form of endochronic (internal time) theory which is actually an elasto-plastic damage theory with isotropicnonlinear kinematic hardening is developed for ease of numerical com...

2018
Jing-Hu Yang Xiang Yu Yi Yang Zeng-Qiang Yang

Underground coal mining activities are prone to cause movement and breakage in geological strata and also lead to mining subsidence and even ground fissures. Along the direction working panel advancing, ground fissures may occur in roof in front and/or behind working panel. However, the investigations of previous similarity tests in lab only emphasize on the region behind working panel. By impr...

Journal: :journal of mining and environment 2015
h. haeri a. r khaloo k. shahriar m. fatehi marji p. moaref vand

in this work, the mechanism for fracture of brittle substances such as rocks under a uniform normal tension is considered. the oriented straight micro-cracks are mostly created in all the polycrystalline materials resulting from the stress concentrations. the present work focuses on the interactions of the pre-existing micro-cracks, which can grow and propagate within a rock-like specimen. the ...

2010
Chao-Shi Chen Chia-Huei Tu Chen-Cheng Yang Oleg V. Gendelman

This paper presents a single-domain boundary element method SDBEM for linear elastic fracture mechanics analysis in the 2D anisotropic bimaterial. In this formulation, the displacement integral equation is collocated on the uncracked boundary only, and the traction integral equation is collocated on one side of the crack surface only. The complete fundamental solution Green’s function for aniso...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی امیرکبیر(پلی تکنیک تهران) - دانشکده مهندسی عمران 1386

در این رساله به بررسی مساله شروع و گسترش ترک های هیدرولیکی قرار گرفته در عرض یک گمانه درحالت کرنش مسطح در محیط سنگی هموژن و الاستیک نفوذناپذیر می پردازیم. ترک ها توسط سیال نیوتنی تراکم پذیر که با نرخ حجمی ثابت به داخل گمانه تزریق می شوند هدایت می شوند. تغییر شکل مصالح مطابق با معادله الاستیسیته خطی و جریان سیال ویسکوز داخل ترک با استفاده از تئوری روانسازی مدل می شود. اثر شعاع محدود گمانه با کرن...

2007
Norbert Blanco Silvestre T. Pinho Paul Robinson

Final failure of laminated composite structures is preceded by different damage mechanisms involving fracture initiation and propagation. Fracture in a composite laminate can appear either between two plies or within a lamina. In the first case, interlaminar fracture or delamination, the crack causes separation of two adjacent plies and will mainly involve matrix failure or matrix-to-fibre debo...

Journal: :J. Nonlinear Science 2010
Jean-Jacques Marigo

The initiation of a crack in a sound body is a real issue in the setting of Griffith’s theory of brittle fracture. If one uses the concept of critical energy release rate (Griffith’s criterion), it is in general impossible to initiate a crack. On the other hand, if we replace it by a least energy principle (Francfort–Marigo’s criterion), it becomes possible to predict the onset of cracking in a...

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