نتایج جستجو برای: rock fracture mechanics

تعداد نتایج: 269205  

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

هدف از انجام این رساله پیش بینی انرژی خردایش سنگ با استفاده از پارامترهای مکانیکی سنگ می باشد. مطالعات انجام شده در اینجا شامل دو بخش می باشند. در بخش اول، فرایند خردایش و کاهش ابعاد سنگ های کروی و مکعبی که بین دو صفحه فولادی بارگذاری می شوند، با استفاده از روش عددی تفاضل محدود شبیه سازی شده است و انرژی کرنشی ذخیره شده در سنگ در هر مرحله بارگذاری محاسبه شده است. نمونه ها به صورت محیط الاستو-پلا...

2016
Hang Deng Catherine A. Peters Jeffrey P. Fitts

This paper presents a new method—the Technique of Iterative Local Thresholding (TILT)—for processing 3D X-ray computed tomography (xCT) images for visualization and quantification of rock fractures. The TILT method includes the following advancements. First, custom masks are generated by a fracture-dilation procedure, which significantly amplifies the fracture signal on the intensity histogram ...

2006
A. GOLSHANI T. TRAN-CONG

Fluid pressure inside a borehole produces hydraulic fracture and damage zones in the vicinity of the borehole. These fractures result from stress concentrations around the borehole. The results of numerical simulation of a borehole subjected to fluid pressure using a micromechanical damage model [2] are presented in this paper. It is observed that tensional concentrated stresses are generated a...

2011

Interfaces between two different mixes or strengths of concrete appear in large concrete structures involving mass concreting such as dams, nuclear containment vessels, cooling towers etc., since joints between successive lifts are inevitable. These joints and interfaces are potential sites for crack formation, leading to weakening of mechanical strength and subsequent failure. Research involvi...

2014
David Cho Marco Perez

The concept of brittleness plays a crucial role in the development of tight oil and gas as it reflects a rock’s ability to fail and maintain a fracture in a hydraulic fracture experiment. Conventional methods that attempt to quantify the degree of brittleness associated with a rock mass have a few shortcomings. For example, failure criteria are not used and only the effective moduli are conside...

2013
Piotr SZYMCZAK P. SZYMCZAK

We briefly review the models of fracture dissolution process, discussing the experimental and numerical evidence showing that this phenomenon is inherently two-dimensional and hence cannot be accurately described by one-dimensional models. The physical reason for this incompatibility is that a dissolution front in a single rock fracture is potentially unstable to small variations in local perme...

2014
J. R. Rice D. M. Tracey

2. Vehicles can be designed to provide crash protection to the occu little or no penalty to the weight and cost of the vehicle. 3. Vehicle crashworthiness can be improved by providing the principles to designers and by emphasizing the importance of this design responsibility. Decisions and design choices can then be · and in cases where two or more comparable choices are possible, the in favor ...

2007
Anthony R. Ingraffea

The classical, overall objective of fracture mechanics is the determination of the rate of change of the shape of an existing crack. Will it propagate under given loading and environmental conditions, and, if it does propagate, at what rate and into what configuration will it do so? The corresponding computational requirement has been to obtain the fields – displacement, strain, stress, and ene...

2007
A. Carpinteri

The so-called Complexity Sciences are a topic of fast growing interest inside the scientific community. Actually, researchers did not come to a definition of complexity, since it manifests itself in so many different ways [1]. This field itself is not a single discipline, but rather a heterogeneous amalgam of different techniques of mathematics and science. In fact, under the label of Complexit...

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