Dynamic Fracture of Heterogeneous Materials

Dynamic Fracture of Heterogeneous Materials PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 15

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Book Description
This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to investigate the fundamental aspects of the process of dynamic fracture propagation in heterogeneous materials. The work focused on three important, but poorly understood, aspects of dynamic fracture for materials with a heterogeneous microstructure. These were: the appropriateness of using a single-parameter asymptotic analysis to describe dynamic crack-tip deformation fields, the temperature rises at the tip and on the flanks of a running crack, and the constitutive modeling of damage initiation and accumulation.

Dynamic Fracture of Heterogeneous Materials

Dynamic Fracture of Heterogeneous Materials PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 15

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Book Description
This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to investigate the fundamental aspects of the process of dynamic fracture propagation in heterogeneous materials. The work focused on three important, but poorly understood, aspects of dynamic fracture for materials with a heterogeneous microstructure. These were: the appropriateness of using a single-parameter asymptotic analysis to describe dynamic crack-tip deformation fields, the temperature rises at the tip and on the flanks of a running crack, and the constitutive modeling of damage initiation and accumulation.

Micromechanical Modeling of Dynamic Fracture in Heterogeneous Materials

Micromechanical Modeling of Dynamic Fracture in Heterogeneous Materials PDF Author: Jun Zhai
Publisher:
ISBN:
Category : Materials
Languages : en
Pages :

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Book Description


Damage and Fracture of Heterogeneous Materials

Damage and Fracture of Heterogeneous Materials PDF Author: Leon L. Mishnaevsky Jr
Publisher: CRC Press
ISBN: 9789054106999
Category : Technology & Engineering
Languages : en
Pages : 240

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Book Description
This work examines problems, particularly in mining and civil engineering, related to the destruction of heterogenous materials. It details the physical mechanisms of destruction, methods of damage and fracture modelling, and the application of models to the improvement of drilling efficiency.

Heterogeneous Materials

Heterogeneous Materials PDF Author: Muhammad Sahimi
Publisher: Springer Science & Business Media
ISBN: 0387217045
Category : Mathematics
Languages : en
Pages : 650

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Book Description
This monograph describes and discusses the properties of heterogeneous materials, comparing two fundamental approaches to describing and predicting materials’ properties. This multidisciplinary book will appeal to applied physicists, materials scientists, chemical and mechanical engineers, chemists, and applied mathematicians.

Dynamic Fracture of Concrete and Other Heterogeneous Materials

Dynamic Fracture of Concrete and Other Heterogeneous Materials PDF Author: T. Belytschko
Publisher:
ISBN:
Category :
Languages : en
Pages : 33

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Book Description
Closed form solutions have been developed for wave propagation problems in materials which have a constitutive equation with strain softening (SS). These solutions have been useful in assessing the performance of finite element programs and in examining the validity of SS models from physical grounds. The salient characteristics of these wave propagation solutions with SS is that the strain softening localizes into a domain of one-dimension smaller than the space of the problem: for example, in a one-dimensional wave propagation problem, the strain softening localizes to a single point where strain softening is first initiated. Furthermore, if the stress goes to zero as the strain increases in the SS discontinuity is introduced in the displacement. A more serious shortcoming is the absence of energy dissipation in the SS part of the continuum. This absence is due to the extreme localization of the SS phenomenon. Since strain-softening models are usually intended to model dissipative processes such as microcracking or crushing of material, the absence of dissipation is quite troublesome. To overcome this drawback of the SS continuum model, a nonlocal theory was examined. In a non-local theory, the stresses depend on an average of the strain in a volume about the point at which the stress is being computed. In this type of theory, the localization which is characteristic of strain softening solutions can be limited and a finite amount of energy dissipation which is relatively insensitive to element size, can be achieved. Keywords: Concrete; Structures; Failures; Size effects.

Dynamic Fracture Mechanics

Dynamic Fracture Mechanics PDF Author: Arun Shukla
Publisher: World Scientific
ISBN: 9812773320
Category : Technology & Engineering
Languages : en
Pages : 374

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Book Description
Covering a wide variety of topics in dynamic fracture mechanics, this volume presents state-of-the-art experimental techniques and theoretical analysis on dynamic fracture in standard and exotic materials. Written by world renowned researchers, this valuable compendium contains eleven chapters on crack initiation, crack propagation, crack arrest, crack-stress wave interactions, and experimental, analytical and numerical methods in dynamic fracture mechanics. Contents: Modeling Dynamic Fracture Using Large-Scale Atomistic Simulations (H-J Gao & M J Buehler); Dynamic Crack Initiation Toughness (D Rittel); The Dynamics of Rapidly Moving Tensile Cracks in Brittle Amorphous Material (J Fineberg); Optical Methods for Dynamic Fracture Mechanics (H V Tippur); On the Use of Strain Gages in Dynamic Fracture (V Parameswaran & A Shukla); Dynamic and Crack Arrest Fracture Toughness (R E Link & R Chona); Dynamic Fracture in Graded Materials (A Shukla & N Jain); Dynamic Fracture Initiation Toughness at Elevated Temperatures with Application to the New Generation of Titanium Aluminides Alloys (M Shazly et al.); Dynamic Fracture of Nanocomposite Materials (A Shukla et al.). Readership: Researchers, practitioners, and graduate students in fracture mechanics and materials science.

Nucleation and Propagation of Fracture in Heterogeneous Materials

Nucleation and Propagation of Fracture in Heterogeneous Materials PDF Author: Gabriele Albertini
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Failure of materials and interfaces is mediated by the propagation of cracks. They nucleate locally and slowly then, as they exceed a critical size, accelerate and reach speeds approaching the speed of sound of the surrounding material. As they propagate, they dissipate energy within a confined region at the crack tip, which approaches a mathematical singularity. As a result, the initiation and propagation of cracks is a spatial and temporal multiscale phenomenon. The framework of linear elastic fracture mechanics captures many aspects related to the dynamic propagation of cracks in homogeneous media. However, the propagation of a crack within a medium with heterogeneous elastic or fracture properties cannot be addressed theoretically. It is in these complex, heterogeneous cases that numerical simulations and experiments shine. The material heterogeneity introduces additional length scales to the problem, which characterize the geometrical properties or spatial correlation of the heterogeneities. The interaction of these geometrical length scales with fracture mechanics related ones is not well understood, but it could provide crucial insights for the design of new materials and interfaces with unprecedented fracture properties. This thesis investigates different aspects of crack nucleation and propagation in heterogeneous materials and interfaces, including nucleation of mode II ruptures on interfaces with random local properties, dynamic mode II rupture propagation within elastically heterogeneous media, and dynamic mode I rupture propagation within a material with periodic heterogeneous fracture energy. In this context, when considering mode II dynamic fracture problems, we are making an analogy to frictional interfaces. In fact, the onset of frictional motion is mediated by crack-like ruptures that nucleate locally and propagate dynamically along the frictional interface. To investigate the complex interaction between fracture mechanics and geometry related length scales we adopt a combined approach using numerical, theoretical, and experimental methods. The numerical simulations consider a continuum governed by the elastodynamic wave equation and allow for a displacement discontinuity (the rupture) along a predefined interface. Depending on the nature of the heterogeneity, the fracture propagation problem is solved using either the finite-element or the spectral-boundary-integral method. Here, we introduce a novel three-dimensional hybrid method, which combines the two former numerical methods to achieve superior computational performance, while allowing modeling of local complexity and heterogeneity. From the experimental side we use state-of-the-art techniques, including ultra-high-speed photography, digital image correlation, and multi-material additive manufactured polymers. We show that random local strength results in three different nucleation regimes depending on the ratio of correlation length to critical nucleation size. We show that elastic heterogeneity parallel to the fracture interface promotes transition to intersonic crack propagation in mode II cracks by means of reflected elastic waves. Finally, our experimental results of a crack propagating within a material with heterogeneous fracture energy show that the crack abruptly adjusts its speed as it enters a tougher region and allow us to derive an equation of motion of a crack at a material discontinuity.

Dynamics of Heterogeneous Materials

Dynamics of Heterogeneous Materials PDF Author: Vitali Nesterenko
Publisher: Springer Science & Business Media
ISBN: 1475735243
Category : Technology & Engineering
Languages : en
Pages : 528

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Book Description
This monograph deals with the behavior of essentially nonlinear heterogeneous materials in processes occurring under intense dynamic loading, where microstructural effects play the main role. This book is not an introduction to the dynamic behavior of materials, and general information available in other books is not included. The material herein is presented in a form I hope will make it useful not only for researchers working in related areas, but also for graduate students. I used it successfully to teach a course on the dynamic behavior of materials at the University of California, San Diego. Another course well suited to the topic may be nonlinear wave dynamics in solids, especially the part on strongly nonlinear waves. About 100 problems presented in the book at the end of each chapter will help the reader to develop a deeper understanding of the subject. I tried to follow a few rules in writing this book: (1) To focus on strongly nonlinear phenomena where there is no small parameter with respect to the amplitude of disturbance, including solitons, shock waves, and localized shear. (2) To take into account phenomena sensitive to materials structure, where typical space scale of material parameters (particle size, cell size) are presented in the models or are variable in experimental research.

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

Dynamic Failure of Materials and Structures

Dynamic Failure of Materials and Structures PDF Author: Arun Shukla
Publisher: Springer Science & Business Media
ISBN: 1441904468
Category : Science
Languages : en
Pages : 416

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Book Description
Dynamic Failure of Materials and Structures discusses the topic of dynamic loadings and their effect on material and structural failure. Since dynamic loading problems are very difficult as compared to their static counterpart, very little information is currently available about dynamic behavior of materials and structures. Topics covered include the response of both metallic as well as polymeric composite materials to blast loading and shock loadings, impact loadings and failure of novel materials under more controlled dynamic loads. These include response of soft materials that are important in practical use but have very limited information available on their dynamic response. Dynamic fragmentation, which has re-emerged in recent years has also been included. Both experimental as well as numerical aspects of material and structural response to dynamic loads are discussed. Written by several key experts in the field, Dynamic Failure of Materials and Structures will appeal to graduate students and researchers studying dynamic loadings within mechanical and civil engineering, as well as in physics and materials science.