Download or read book Cohesive Modeling of Dynamic Fracture written by Dhirendra V. Kubair and published by . This book was released on 2001 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Fracture Mechanics written by L. B. Freund and published by Cambridge University Press. This book was released on 1998-03-28 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume focuses on the development and analysis of mathematical models of fracture phenomena.

Download or read book Dynamic Fracture Mechanics written by Arun Shukla and published by World Scientific. This book was released on 2006 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Extrinsic Cohesive Modeling of Dynamic Fracture and Microbranching Instability Using a Topological Data Structure written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Fracture written by K. Ravi-Chandar and published by Elsevier. This book was released on 2004-10-16 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Dynamics of Fracture written by N. Morozov and published by Springer Science & Business Media. This book was released on 2013-06-05 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book a new phenomenological approach to brittle medium fracture initiation under shock pulses is developped. It provides an opportunity to estimate fracture of media with and without macrodefects. A qualitative explanation is thus obtained for a number of principally important effects of high-speed dynamic fracture that cannot be clarified within the framework of previous approaches. It is possible to apply this new strategy to resolve applied problems of disintegration, erosion, and dynamic strength determination of structural materials. Specialists can use the methods described to determine critical characteristics of dynamic strength and optimal effective fracture conditions for rigid bodies. This book can also be used as a special educational course on deformation of materials and constructions, and fracture mechanics.

Download or read book Models and Phenomena in Fracture Mechanics written by Leonid I. Slepyan and published by Springer Science & Business Media. This book was released on 2012-11-07 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting the most important results, methods, and open questions, this book describes and compares advanced models in fracture mechanics. The author introduces the required mathematical technique, mainly the theory of analytical functions, from scratch.

Download or read book Dynamic Fracture Mechanics Propagating cracks written by Vladimir Zalmanovich Parton and published by . This book was released on 1989 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spacetime Damage based Cohesive Model for Elastodynamic Fracture with Dynamic Contact written by Reza Abedi and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic material failure is important in a number of scientific and engineering applications and a variety of numerical methods for its modeling have been proposed. This thesis presents the formulation and implementation of an interfacial-damage, cohesive-fracture model, including contact and friction effects, for dynamic failure of brittle materials. The model is implemented within a spacetime discontinuous Galerkin (SDG) finite element method. An adaptive meshing procedure generates %When implemented on suitable spacetime grids that satisfy a special causality constraint to enable an efficient patch-by-patch, advancing-front solution scheme with O(N) computational complexity. Per-element balance properties, local adaptive operations, and the use of Riemann fluxes provide to the SDG method the extreme accuracy and efficiency required to solve multiscale fracture problems. A dimensional analysis of linear elastodynamics, with extensions to fracture models based on cohesive traction--separation laws, supports the formulation. The problem is formulated and analyzed using differential forms and the exterior calculus in spacetime. The analysis demonstrates that the velocity scalings implied by the spatial and temporal coordinate scalings and by the scalings of the material properties must be identical to obtain a self-similar scaling of an elastodynamic process. The use of differential forms reveals intrinsic structure and relations between the spacetime mechanics fields which are otherwise obscured by conventional tensorial analysis. For example, only four distinct scalings are required to define a scaled elastodynamic process when we work directly with forms, while eight are required when tensorial analysis is used. In the context of dynamic cohesive fracture, the analysis shows that, among the nondimensional variables, the ratio of the stress-loading scale to the cohesive strength is proportional to the ratio of the radius of the singularity-dominant zone from Linear Elastodynamic Fracture Mechanics (LEFM), to the cohesive-process-zone size. These ratios are, in turn, useful indicators of whether the small-scale-yielding caveat of LEFM is satisfied. A novel continuum formulation of the linear elastodynamic contact problem also supports the SDG finite element model. In contrast to previous contact models that invoke quasi-static contact conditions, the proposed model enforces dynamic contact conditions by prescribing momentum flux and compatibility conditions obtained from the local Riemann problems for bonded, separation, contact--stick, and contact--slip modes. This approach preserves the characteristic structure of the underlying equations at the contact interface, a property that is lacking in previous formulations. The fully-bonded and contact--stick conditions are identical, as expected, so the non-penetration and tangential slip constraints are treated exactly in the new continuum formulation. Furthermore, the direction of the tangential contact traction (friction) is shown to be continuous through transitions between contact--stick and contact-slip modes. These favorable properties, which improve the accuracy of and facilitate numerical implementations of the proposed model, are not obtained in many existing models which, for example, replace the non-penetration constraint with a large interfacial stiffness in the normal direction. %For example, the required continuity conditions are replaced with large penetration stiffness values in penalty methods. % Furthermore, it is shown that the relative tangential velocity in slip mode is aligned with the tangential traction that would have resulted under the stick mode. It is well documented that the determination of slip traction from slip velocity is discontinuous and poses several difficulties in numerical methods. The choice of stick tranction, on the otherhand, provides a continuous representation for the direction of slip traction. % The direction of slip traction is determined from the slip velocity in Coulomb law of friction. However, the discontinuous nature of this representation causes several difficulties in the numerical methods. It is shown that the orientation derived from a tangential traction that would have acted in stick mode eliminates the discontinuity. The transition between separation and contact modes retains its physically discontinuous character, and a regularization of this transition is introduced to facilitate and reduce the cost of numerical implementations. A discretization and numerical implementation within the adaptive SDG framework demonstrate the effectiveness of the new contact model in a numerical setting. A new two-scale cohesive fracture model replaces the usual traction-separation law with a damage model that represents mesoscale processes of void growth and coalescence. The evolution of a single damage parameter D, which represents the debonded area fraction on cohesive interfaces, is governed by an irreversible, time-delay evolution law characterized by a cohesive strength and a relaxation time that determines the maximum damage rate. Riemann fluxes for the fully-bonded condition are enforced in the undamaged area fraction (1-D) of the cohesive interface, while the Riemann fluxes for the contact--stick, contact--slip or separation conditions determine the fluxes in the debonded area fraction. These mesoscale Riemann values are averaged to derive macroscopic cohesive conditions. % The damage-based cohesive model is implemented within the adaptive SDG finite element framework to produce a numerical model that efficiently and accurately resolves the multi-scale response associated with dynamic fracture and transitions between contact, separation, stick and slip conditions in the event of crack closure. Beyond ensuring solution accuracy, the model uses the SDG scheme's adaptive meshing capabilities to freely nucleate and extend cohesive interfaces to capture solution-dependent crack paths. The SDG adaptive meshing aligns the boundaries of spacetime elements with crack-path trajectories having arbitrary position and orientation, and two adaptive error indicators ensure the accurate rendering of both the cohesive model and the bulk solution. Thus, the present model does not suffer the limited resolution and mesh-dependent effects encountered in most other numerical fracture models. Numerical results obtained with the proposed model demonstrate crack propagation, microcrack formation and crack branching phenomena.

Download or read book A Mixed Eulerian Lagrangian Model for the Analysis of Dynamic Fracture written by Hyun Moo Koh and published by . This book was released on 1986 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cracks and Fracture written by K. Bertram Broberg and published by Elsevier. This book was released on 1999-02-24 with total page 771 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cracks and Fracture consists of nine chapters in logical sequence. In two introductory chapters, physical processes in the vicinity of the crack edge are discussed and the fracture process is described. Chapter 3 develops general basic concepts and relations in crack mechanics, such as path independent integrals, stress intensity factors and energy flux into the crack edge region. Chapters 4-7 deal with elastostatic cracks, stationary or slowly moving elastic-plastic cracks, elastodynamic crack mechanics and elastoplastic aspects of fracture, including dynamic fracture mechanics. Appendices include general formulae, the basic theory of analytic functions, introduction to Laplace and Hankel transforms and description of certain basic relations, for instance for stress waves in solids. There is an extensive bibliography, containing references to both classical and recent work, and a comprehensive index. Presents an extensive bibliography containing references to both classical and recent works and a comprehensive index Appendices include general formulas, the basic theory of analytic functions, introduction to Laplace and Hankel transforms, and descriptions of certain basic relations, for instance for stress waves in solids

Download or read book Fracture Mechanics written by Chin-Teh Sun and published by Academic Press. This book was released on 2011-10-14 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: From a leading expert in fracture mechanics, this text provides new approaches and new applications to advance the understanding of crack formation and propagation.

Download or read book Atomistic Modeling of Materials Failure written by Markus J. Buehler and published by Springer Science & Business Media. This book was released on 2008-08-07 with total page 547 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an introduction to molecular and atomistic modeling techniques applied to fracture and deformation of solids, focusing on a variety of brittle, ductile, geometrically confined and biological materials. The overview includes computational methods and techniques operating at the atomic scale, and describes how these techniques can be used to model cracks and other deformation mechanisms. The book aims to make new molecular modeling techniques available to a wider community.

Download or read book An Improved Cohesive Zone Model for Ductile Dynamic Crack Propagation written by Marc Sagimon Buch and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ductile dynamic crack propagation is a current field of research in aerospace industry. The damage created by an explosion in a flying airplane depends on the fracture behaviour of the fuselage materials. Thus the rate of fracture for aluminium 2024 T3 is being studied. Analytical and empirical calculation methods do not predict correctly the experimental fracture velocity. Numerical simulations using cohesive elements with standard material models do not estimate it correctly either. Then a new numerical approach is being carried out which is focussed on a rate dependent (Perzyna) cohesive zone model. Basically, in this model the energy dissipated during the fracture depends on the fracture loading rate. To improve the accuracy of the time integration of the constitutive equations, an implicit scheme has been implemented and it has been checked the situations where a previous explicit implementation may be less accurate. New fracture experiments on aluminium pressurized barrels have been modeled using the Perzyna model. The results show a good agreement in terms crack behaviour and crack velocity. In addition it has been observed a big influence of the loads in fracture speed during the crack propagation.

Download or read book Comprehensive Structural Integrity written by Ian Milne and published by Elsevier. This book was released on 2003-07-25 with total page 4647 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this major reference work is to provide a first point of entry to the literature for the researchers in any field relating to structural integrity in the form of a definitive research/reference tool which links the various sub-disciplines that comprise the whole of structural integrity. Special emphasis will be given to the interaction between mechanics and materials and structural integrity applications. Because of the interdisciplinary and applied nature of the work, it will be of interest to mechanical engineers and materials scientists from both academic and industrial backgrounds including bioengineering, interface engineering and nanotechnology. The scope of this work encompasses, but is not restricted to: fracture mechanics, fatigue, creep, materials, dynamics, environmental degradation, numerical methods, failure mechanisms and damage mechanics, interfacial fracture and nano-technology, structural analysis, surface behaviour and heart valves. The structures under consideration include: pressure vessels and piping, off-shore structures, gas installations and pipelines, chemical plants, aircraft, railways, bridges, plates and shells, electronic circuits, interfaces, nanotechnology, artificial organs, biomaterial prostheses, cast structures, mining... and more. Case studies will form an integral part of the work.

Download or read book Crack Dynamics written by Alojz Ivankovic and published by WIT Press (UK). This book was released on 2005 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering various aspects of dynamic fractures this book contains state-of-the-art contributions from leading scientists in the field of crack dynamics.

Download or read book Speed Effects on Moving Cracks in Nonlinear ductile Materials written by Jian Wu and published by . This book was released on 2014 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Speed effects on moving cracks in ductile or nonlinear materials are studied with newly developed theoretical models in the present thesis. Speed-dependent stress field, traction distribution and fracture energy are discussed in detail in four chapters. 1) An asymptotic analysis near the tip of a steady-state moving crack in a compressible hyperelastic material is given based on a finite plane strain model. The crack tip deformation and stress fields are derived up to the third order which meets the strict positivity of Jacobian determinant in the vicinity of the moving crack tip. Comparison with the experimental data shows that the crack-face profile and the energy release rate predicted by the present model are in reasonable agreement with experiments and several recent nonlinear elastic models. In addition, the crack branching angle predicted by the present model also agrees well with some known experimental data. 2) Steady-state moving crack under mode-I loading is studied with a modified cohesive zone model which addresses speed-dependent role of the normal stress parallel to the crack axis and the non-uniformity of traction force in cohesive zone. Unlike the classical Dugdale model which predicts independence of the cohesive zone length on crack speed, the present modified model predicts that the cohesive zone length strongly depends on crack speed. Comparison with some known experimental data suggests that the present modified model has the potential to capture the speed effects on moving cracks in ductile materials especially at high crack speed. 3) The modified cohesive zone model is then applied to a self-similar high-speed expanding crack problem. Numerical results show that the normal stress parallel to the crack face increases with increasing crack speed and can be even larger than the normal traction in the cohesive zone, which justifies the necessity of including the normal stress parallel to the crack faces in the yielding condition at high crack speed. Strain hardening effect is also examined based on a non-uniform traction distribution given by a polynomial whose coefficients are to be determined as part of the solution. 4) A simple mass-spring model is presented to study inertia effect of cohesive zone for a Yoffe-type mode-I steady-state moving crack of constant length. Traction distribution surrounding the cohesive zone and fracture energy at high crack speed are solved numerically by a proposed numerical method. Results show that fracture energy predicted by the present model increases significantly at high crack speed, which defines a limiting crack speed above that fracture energy tends to infinity. Reasonable agreement with some known experimental data suggests that the present model has the potential to catch inertia effect of cohesive zone of a high-speed moving crack which has not been considered by existing cohesive zone models. The theoretical models and numerical results achieved in this thesis contribute new ideas and insights into the study of high-speed dynamic fracture of nonlinear and ductile materials, and some results predicted by the present models provide plausible explanations for a few important phenomena of moving cracks at high crack speed which have not been well explained by the existing models.