Download or read book Nucleation and Propagation of Fracture in Heterogeneous Materials written by Gabriele Albertini and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Damage and Fracture of Heterogeneous Materials written by Leon L. Mishnaevsky Jr and published by CRC Press. This book was released on 1998-01-01 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Heterogeneous Materials written by Muhammad Sahimi and published by Springer Science & Business Media. This book was released on 2006-05-31 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Quantitiative Phase field Modeling of Crack Propagation in Multi phase Materials written by Arezoo Emdadi and published by . This book was released on 2018 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Research presented in this dissertation is focused on developing and validating a computational framework for study of crack propagation in polycrystalline composite ceramics capable of designing micro-architectures of phases to improve fracture toughness and damage tolerance of ZrB2-based ultra-high temperature ceramics (UHTCs). A quantitative phase-field model based on the regularized formulation of Griffith's theory is presented for crack propagation in homogenous and heterogeneous brittle materials. This model utilizes correction parameters in the total free energy functional and mechanical equilibrium equation within the crack diffusive area to ensure that the maximum stress in front of the crack tip is equal to the stress predicted by classical fracture mechanics. Also, unlike other phase-field models, the effect of material strength on crack nucleation and propagation was considered. The accuracy of the model is benchmarked in different ways and the simulation results are validated against experimental results for concrete in the form of fracture of L-shaped plates and wedge splitting tests, and for ZrB2-based laminates and fibrous monolithic composites. To study crack propagation in polycrystalline systems, a phase-field model for grain growth is coupled to the proposed model for crack propagation in multi-phase systems. Intergranular and transgranular crack propagation in ZrB2-bicrystal and polycrystalline systems in mode-I loading are studied. The significant advantages of the proposed model are revealed in multi-phase systems with considerably different material properties for different phases in which the model enables accurate predication of the crack propagation path in composites consisting of materials with significantly different strengths"--Abstract, page iv.
Download or read book Fracture of Structural Materials written by A. S. Tetelman and published by John Wiley & Sons. This book was released on 1967 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Variational Approach to Fracture written by Blaise Bourdin and published by Springer Science & Business Media. This book was released on 2008-04-19 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Advances in Applied Mechanics written by Daniel S. Balint and published by Academic Press. This book was released on 2020-10-23 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Applied Mechanics, Volume 53 in this ongoing series, highlights new advances in the field, with this new volume presenting interesting chapters on Phase field modelling of fracture, Advanced geometry representations and tools for microstructural and multiscale modelling, The material point method: the past and the future, From Experimental Modeling of Shotcrete to Large Scale Numerical Simulations of Tunneling, and Material point method after 25 years: theory, implementation, applications. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Advances in Applied Mechanics series
Download or read book Proceedings of 8th GACM Colloquium on Computational Mechanics written by Tobias Gleim and published by kassel university press GmbH. This book was released on 2019-09-04 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: This conference book contains papers presented at the 8th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry. The conference was held from August 28th – 30th, 2019 in Kassel, hosted by the Institute of Mechanics and Dynamics of the department for civil and environmental engineering and by the chair of Engineering Mechanics / Continuum Mechanics of the department for mechanical engineering of the University of Kassel. The aim of the conference is, to bring together young scientits who are engaged in academic and industrial research on Computational Mechanics and Computer Methods in Applied Sciences. It provides a plattform to present and discuss recent results from research efforts and industrial applications. In more than 150 presentations, given by young scientists, current scientific developments and advances in engineering practice in this field are presented and discussed. The contributions of the young researchers are supplemented by a poster session and plenary talks from four senior scientists from academia and industry as well as from the GACM Best PhD Award winners 2017 and 2018.
Download or read book Topics in Fracture and Fatigue written by A.S. Argon and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture in structural materials remains a vital consideration in engineering systems, affecting the reliability of machines throughout their lives. Impressive advances in both the theoretical understanding of fracture mechanisms and practical developments that offer possibilities of control have re-shaped the subject over the past four decades. The contributors to this volume, including some of the most prominent researchers in the field, give their long-range perspectives of the research on the fracture of solids and its achievements. The subjects covered in this volume include: statistics of brittle fracture, transition of fracture from brittle to ductile, mechanics and mechanisms of ductile separation of heterogenous solids, the crack tip environment in ductile fracture, and mechanisms and mechanics of fatigue. Materials considered range from the usual structural solids to composites. The chapters include both theoretical points of view and discussions of key experiments. Contributors include: from MIT, A.S. Argon, D.M. Parks; from Cambridge, M.F. Ashby; from U.C. Santa Barbara, A.G. Evans, R. McMeeking; from Glasgow, J. Hancock; from Harvard, J.W. Hutchinson, J.R. Rice; from Sheffield, K.J. Miller; from Brown, A. Needleman; from the Ecole des Mines, A. Pineau; from U.C. Berkeley, R. O. Ritchie; and from Copenhagen, V. Tvergaard.
Download or read book Dynamic Fracture of Heterogeneous Materials written by and published by . This book was released on 1998 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Topology Optimization Design of Heterogeneous Materials and Structures written by Daicong Da and published by John Wiley & Sons. This book was released on 2020-02-26 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book pursues optimal design from the perspective of mechanical properties and resistance to failure caused by cracks and fatigue. The book abandons the scale separation hypothesis and takes up phase-field modeling, which is at the cutting edge of research and is of high industrial and practical relevance. Part 1 starts by testing the limits of the homogenization-based approach when the size of the representative volume element is non-negligible compared to the structure. The book then introduces a non-local homogenization scheme to take into account the strain gradient effects. Using a phase field method, Part 2 offers three significant contributions concerning optimal placement of the inclusion phases. Respectively, these contributions take into account fractures in quasi-brittle materials, interface cracks and periodic composites. The topology optimization proposed has significantly increased the fracture resistance of the composites studied.
Download or read book Physical Aspects of Fracture written by Elisabeth Bouchaud and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main scope of this Cargese NATO Advanced Study Institute (June 5-17 2000) was to bring together a number of international experts, covering a large spectrum of the various Physical Aspects of Fracture. As a matter of fact, lecturers as well as participants were coming from various scientific communities: mechanics, physics, materials science, with the common objective of progressing towards a multi-scale description of fracture. This volume includes papers on most materials of practical interest: from concrete to ceramics through metallic alloys, glasses, polymers and composite materials. The classical fields of damage and fracture mechanisms are addressed (critical and sub-critical quasi-static crack propagation, stress corrosion, fatigue, fatigue-corrosion . . . . as well as dynamic fracture). Brittle and ductile fractures are considered and a balance has been carefully kept between experiments, simulations and theoretical models, and between the contributions of the various communities. New topics in damage and fracture mechanics - the effect of disorder and statistical aspects, dynamic fracture, friction and fracture of interfaces - were also explored. This large overview on the Physical Aspects of Fracture shows that the old barriers built between the different scales will soon "fracture". It is no more unrealistic to imagine that a crack initiated through a molecular dynamics description could be propagated at the grain level thanks to dislocation dynamics included in a crystal plasticity model, itself implemented in a finite element code. Linking what happens at the atomic scale to fracture of structures as large as a dam is the new emerging challenge.
Download or read book Computational Modelling of Concrete Structures written by Günther Meschke and published by CRC Press. This book was released on 2018-01-31 with total page 1034 pages. Available in PDF, EPUB and Kindle. Book excerpt: The EURO-C conference series (Split 1984, Zell am See 1990, Innsbruck 1994, Badgastein 1998, St. Johann im Pongau 2003, Mayrhofen 2006, Schladming 2010, St. Anton am Arlberg 2014, and Bad Hofgastein 2018) brings together researchers and practising engineers concerned with theoretical, algorithmic and validation aspects associated with computational simulations of concrete and concrete structures. Computational Modelling of Concrete Structures reviews and discusses research advancements and the applicability and robustness of methods and models for reliable analysis of complex concrete, reinforced concrete and pre-stressed concrete structures in engineering practice. The contributions cover both computational mechanics and computational modelling aspects of the analysis and design of concrete and concrete structures: Multi-scale cement and concrete research: experiments and modelling Aging concrete: from very early ages to decades-long durability Advances in material modelling of plain concrete Analysis of reinforced concrete structures Steel-concrete interaction, fibre-reinforced concrete, and masonry Dynamic behaviour: from seismic retrofit to impact simulation Computational Modelling of Concrete Structures is of special interest to academics and researchers in computational concrete mechanics, as well as industry experts in complex nonlinear simulations of concrete structures.
Download or read book Recent Advances in Applied Mechanics written by Tezeswi Tadepalli and published by Springer Nature. This book was released on 2022-04-04 with total page 743 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises the proceedings of the Virtual Seminar on Applied Mechanics 2021 organized by the Indian Society for Applied Mechanics. The contents of this volume focus on solid mechanics, fluid mechanics, biomechanics/biomedical engineering, materials science and design engineering. The authors are experienced practitioners and the chapters encompass up-to-date research in the field of applied mechanics. This book will appeal to researchers and scholars across the broad spectrum of engineering involving the application of mechanics in civil, mechanical, aerospace, automobile, bio-medical, material science, and more.
Download or read book The Fiber Bundle written by Ferenc Kun and published by Frontiers Media SA. This book was released on 2022-01-10 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Frattura ed Integrit Strutturale Annals 2012 written by Francesco Iacoviello and published by Gruppo Italiano Frattura. This book was released on 2012-10-03 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Multi Physics and Multi Scale Couplings in Geo Environmental Mechanics written by Francois Nicot and published by Elsevier. This book was released on 2017-11-20 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Multi-Physics and Multi-Scale Couplings in Geo-Environmental Mechanics reunites some of the most recent work from the French research group MeGe GDR (National Research Group on Multiscale and Multiphysics Couplings in Geo-Environmental Mechanics) on the theme of multi-scale and multi-physics modeling of geomaterials, with a special focus on micromechanical aspects. Its offers readers a glimpse into the current state of scientific knowledge in the field, together with the most up-to-date tools and methods of analysis available. Each chapter represents a study with a different viewpoint, alternating between phenomenological/micro-mechanically enriched and purely micromechanical approaches. Throughout the book, contributing authors will highlight advances in geomaterials modeling, while also pointing out practical implications for engineers. Topics discussed include multi-scale modeling of cohesive-less geomaterials, including multi-physical processes, but also the effects of particle breakage, large deformations on the response of the material at the specimen scale and concrete materials, together with clays as cohesive geomaterials. The book concludes by looking at some engineering problems involving larger scales. - Identifies contributions in the field of geomechanics - Focuses on multi-scale linkages at small scales - Presents numerical simulations by discrete elements and tools of homogenization or change of scale
