A Gradient-damage Theory for Quasi Brittle Fracture

A Gradient-damage Theory for Quasi Brittle Fracture PDF Author: Sooraj Narayan
Publisher:
ISBN:
Category :
Languages : en
Pages : 88

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Book Description
Phase-field modeling of brittle fracture of linear elastic solids has been the subject of several studies in the past 25 years. An attractive feature of this approach to model fracture is its seamless ability to simulate the complicated fracture processes of nucleation, propagation, branching and merging of cracks in arbitrary geometries. While most existing models have focussed on fracture of "ideal brittle" materials, we consider fracture of "quasi-brittle" materials. The material is considered to be quasi-brittle in the sense that it does not lose its entire load-carrying capacity at the onset of damage. Instead there is a gradual degradation of the strength of the material, which is the result of microscale decohesion/damage micromechanisms. In this thesis we discuss the formulation of our gradient-damage theory for quasi-brittle fracture using the virtual-power method. The macro- and microforce balances, obtained from the virtual power approach, together with a standard free-energy imbalance law under isothermal conditions, when supplemented with a set of thermodynamically-consistent constitutive equations will provide the governing equations for our theory. We have specialized our general theory to formulate a simple continuum model for fracture of concrete - a quasi-brittle material of vast importance. We have numerically implemented our theory in a finite element program, and simulated numerical examples which show the ability of the simulation capability to reproduce the macroscopic characteristics of the failure of concrete in several technically relevant geometries reported in the literature..

A Gradient-damage Theory for Quasi Brittle Fracture

A Gradient-damage Theory for Quasi Brittle Fracture PDF Author: Sooraj Narayan
Publisher:
ISBN:
Category :
Languages : en
Pages : 88

Get Book Here

Book Description
Phase-field modeling of brittle fracture of linear elastic solids has been the subject of several studies in the past 25 years. An attractive feature of this approach to model fracture is its seamless ability to simulate the complicated fracture processes of nucleation, propagation, branching and merging of cracks in arbitrary geometries. While most existing models have focussed on fracture of "ideal brittle" materials, we consider fracture of "quasi-brittle" materials. The material is considered to be quasi-brittle in the sense that it does not lose its entire load-carrying capacity at the onset of damage. Instead there is a gradual degradation of the strength of the material, which is the result of microscale decohesion/damage micromechanisms. In this thesis we discuss the formulation of our gradient-damage theory for quasi-brittle fracture using the virtual-power method. The macro- and microforce balances, obtained from the virtual power approach, together with a standard free-energy imbalance law under isothermal conditions, when supplemented with a set of thermodynamically-consistent constitutive equations will provide the governing equations for our theory. We have specialized our general theory to formulate a simple continuum model for fracture of concrete - a quasi-brittle material of vast importance. We have numerically implemented our theory in a finite element program, and simulated numerical examples which show the ability of the simulation capability to reproduce the macroscopic characteristics of the failure of concrete in several technically relevant geometries reported in the literature..

The Variational Approach to Fracture

The Variational Approach to Fracture PDF Author: Blaise Bourdin
Publisher: Springer Science & Business Media
ISBN: 1402063954
Category : Technology & Engineering
Languages : en
Pages : 173

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Book Description
Presenting original results from both theoretical and numerical viewpoints, this text offers a detailed discussion of the variational approach to brittle fracture. This approach views crack growth as the result of a competition between bulk and surface energy, treating crack evolution from its initiation all the way to the failure of a sample. The authors model crack initiation, crack path, and crack extension for arbitrary geometries and loads.

The Scaled Boundary Finite Element Method

The Scaled Boundary Finite Element Method PDF Author: Chongmin Song
Publisher: John Wiley & Sons
ISBN: 1119388457
Category : Science
Languages : en
Pages : 775

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Book Description
An informative look at the theory, computer implementation, and application of the scaled boundary finite element method This reliable resource, complete with MATLAB, is an easy-to-understand introduction to the fundamental principles of the scaled boundary finite element method. It establishes the theory of the scaled boundary finite element method systematically as a general numerical procedure, providing the reader with a sound knowledge to expand the applications of this method to a broader scope. The book also presents the applications of the scaled boundary finite element to illustrate its salient features and potentials. The Scaled Boundary Finite Element Method: Introduction to Theory and Implementation covers the static and dynamic stress analysis of solids in two and three dimensions. The relevant concepts, theory and modelling issues of the scaled boundary finite element method are discussed and the unique features of the method are highlighted. The applications in computational fracture mechanics are detailed with numerical examples. A unified mesh generation procedure based on quadtree/octree algorithm is described. It also presents examples of fully automatic stress analysis of geometric models in NURBS, STL and digital images. Written in lucid and easy to understand language by the co-inventor of the scaled boundary element method Provides MATLAB as an integral part of the book with the code cross-referenced in the text and the use of the code illustrated by examples Presents new developments in the scaled boundary finite element method with illustrative examples so that readers can appreciate the significant features and potentials of this novel method—especially in emerging technologies such as 3D printing, virtual reality, and digital image-based analysis The Scaled Boundary Finite Element Method: Introduction to Theory and Implementation is an ideal book for researchers, software developers, numerical analysts, and postgraduate students in many fields of engineering and science.

Quasibrittle Fracture Mechanics and Size Effect

Quasibrittle Fracture Mechanics and Size Effect PDF Author: Jia-Liang Le
Publisher: Oxford University Press
ISBN: 0192846248
Category : Brittleness
Languages : en
Pages : 332

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Book Description
Many modern engineering structures are composed of brittle heterogenous, or quasibrittle, materials. These include concrete, composites, tough ceramics, rocks, cold asphalt mixtures, and many brittle materials at the microscale. Understanding the failure behavior of these materials is of paramount importance for improving the resilience and sustainability of various engineering structures including civil infrastructure, aircraft, ships, military armors, and microelectronic devices. Designed for graduate and upper-level undergraduate university courses, this textbook provides a comprehensive treatment of quasibrittle fracture mechanics. It includes a concise but rigorous examination of linear elastic fracture mechanics, which is the foundation of all fracture mechanics. It also covers the fundamental concepts of nonlinear fracture mechanics, and introduces more advanced concepts such as triaxial stress state in the fracture process zone, nonlocal continuum models, and discrete computational models. Finally, the book features extensive discussion of the various practical applications of quasibrittle fracture mechanics across different structures and engineering disciplines, and throughout includes exercises and problems for students to test their understanding.

Probabilistic Mechanics of Quasibrittle Structures

Probabilistic Mechanics of Quasibrittle Structures PDF Author: Zdenek P. Bazant
Publisher: Cambridge University Press
ISBN: 1107151708
Category : Science
Languages : en
Pages : 319

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Book Description
This book presents an experimentally validated probabilistic strength theory of structures made of concrete, composites, ceramics and other quasibrittle materials.

Fracture and Damage in Quasibrittle Structures

Fracture and Damage in Quasibrittle Structures PDF Author: Z.P. Bazant
Publisher: CRC Press
ISBN: 9780203223758
Category : Architecture
Languages : en
Pages : 672

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Book Description
Understanding of failure of quasibrittle materials is of paramount importance in many engineering fields. This subject has become a broad and important field of considerable mathematical complexity, with many competing models and unsolved problems. Attention in this volume focuses on concrete, rock, masonry, toughened ceramics, ice and other quasibrittle materials characterized by the development of large zones of cracking or other microstructural damage, and its localization into major fractures.

Dynamic Fracture

Dynamic Fracture PDF Author: K. Ravi-Chandar
Publisher: Elsevier
ISBN: 0080472559
Category : Science
Languages : en
Pages : 265

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Book Description
Dynamic fracture in solids has attracted much attention for over a century from engineers as well as physicists due both to its technological interest and to inherent scientific curiosity. Rapidly applied loads are encountered in a number of technical applications. In some cases such loads might be applied deliberately, as for example in problems of blasting, mining, and comminution or fragmentation; in other cases, such dynamic loads might arise from accidental conditions. Regardless of the origin of the rapid loading, it is necessary to understand the mechanisms and mechanics of fracture under dynamic loading conditions in order to design suitable procedures for assessing the susceptibility to fracture. Quite apart from its repercussions in the area of structural integrity, fundamental scientific curiosity has continued to play a large role in engendering interest in dynamic fracture problems In-depth coverage of the mechanics, experimental methods, practical applications Summary of material response of different materials Discussion of unresolved issues in dynamic fracture

Damage Mechanics

Damage Mechanics PDF Author: George Z. Voyiadjis
Publisher: CRC Press
ISBN: 1420027832
Category : Science
Languages : en
Pages : 275

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Book Description
Before a structure or component can be completed, before any analytical model can be constructed, and even before the design can be formulated, you must have a fundamental understanding of damage behavior in order to produce a safe and effective design. Damage Mechanics presents the underlying principles of continuum damage mechanics along with the

Multifield Problems in Solid and Fluid Mechanics

Multifield Problems in Solid and Fluid Mechanics PDF Author: Rainer Helmig
Publisher: Springer Science & Business Media
ISBN: 3540349618
Category : Technology & Engineering
Languages : en
Pages : 569

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Book Description
This book gives an overview of the research projects within the SFB 404 "Mehrfeldprobleme in der Kontinuumsmechanik". The book is for researchers and graduate students in applied mechanics and civil engineering.

Modeling and Analysis of Damage and Failure of Concrete-Like, Brittle and Quasi-brittle Materials

Modeling and Analysis of Damage and Failure of Concrete-Like, Brittle and Quasi-brittle Materials PDF Author: Dan Huang
Publisher:
ISBN: 9783725804948
Category : Science
Languages : en
Pages : 0

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Book Description
The modeling and analysis of the damage and failure of materials and structures is an active and persistent challenge in computational mechanics, materials, and various scientific and industrial fields. This reprint provides an informative and stimulating forum to enhance academic communications on this challenging topic, focusing on the development and applications of computational theories, numerical and experimental methods, models, and algorithms for modeling and analyzing the damage and failure of concrete-like, brittle, and quasi-brittle materials and structures.