Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Simulations Of Dynamic Crack Propagation In Brittle Materials Using Nodal Cohesive Forces And Continuum Damage Mechanics In The Distinct Element Code Ldec
Download Simulations Of Dynamic Crack Propagation In Brittle Materials Using Nodal Cohesive Forces And Continuum Damage Mechanics In The Distinct Element Code Ldec full books in PDF, epub, and Kindle. Read online Simulations Of Dynamic Crack Propagation In Brittle Materials Using Nodal Cohesive Forces And Continuum Damage Mechanics In The Distinct Element Code Ldec ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Simulations of Dynamic Crack Propagation in Brittle Materials Using Nodal Cohesive Forces and Continuum Damage Mechanics in the Distinct Element Code LDEC. by :
Download or read book Simulations of Dynamic Crack Propagation in Brittle Materials Using Nodal Cohesive Forces and Continuum Damage Mechanics in the Distinct Element Code LDEC. written by and published by . This book was released on 2006 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental data indicates that the limiting crack speed in brittle materials is less than the Rayleigh wave speed. One reason for this is that dynamic instabilities produce surface roughness and microcracks that branch from the main crack. These processes increase dissipation near the crack tip over a range of crack speeds. When the scale of observation (or mesh resolution) becomes much larger than the typical sizes of these features, effective-medium theories are required to predict the coarse-grained fracture dynamics. Two approaches to modeling these phenomena are described and used in numerical simulations. The first approach is based on cohesive elements that utilize a rate-dependent weakening law for the nodal cohesive forces. The second approach uses a continuum damage model which has a weakening effect that lowers the effective Rayleigh wave speed in the material surrounding the crack tip. Simulations in this paper show that while both models are capable of increasing the energy dissipated during fracture when the mesh size is larger than the process zone size, only the continuum damage model is able to limit the crack speed over a range of applied loads. Numerical simulations of straight-running cracks demonstrate good agreement between the theoretical predictions of the combined models and experimental data on dynamic crack propagation in brittle materials. Simulations that model crack branching are also presented.
Book Synopsis Multiscale and Multiphysics Processes in Geomechanics by : Ronaldo I. Borja
Download or read book Multiscale and Multiphysics Processes in Geomechanics written by Ronaldo I. Borja and published by Springer Science & Business Media. This book was released on 2011-05-10 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: This state-of-the-art book contains all results and papers of the International Workshop on Multiscale and Multiphysics Processes in Geomechanics at Stanford University Campus, June 23–25, 2010.
Book Synopsis Rock Mechanics: Meeting Society's Challenges and Demands, Two Volume Set by : Erik Eberhardt
Download or read book Rock Mechanics: Meeting Society's Challenges and Demands, Two Volume Set written by Erik Eberhardt and published by CRC Press. This book was released on 2007-05-17 with total page 1772 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ore extraction through surface and underground mining continues to involve deeper excavations in more complex rock mass conditions. Communities and infrastructure are increasingly exposed to rock slope hazards as they expand further into rugged mountainous terrains. Energy needs are accelerating the development of new hydroelectric dams and exploit
Author :Fleming Petri, Wagner Carlos Publisher :kassel university press GmbH ISBN 13 :3862194361 Total Pages :233 pages Book Rating :4.8/5 (621 download)
Book Synopsis Static and Dynamic Crack Propagation in Brittle Materials with XFEM by : Fleming Petri, Wagner Carlos
Download or read book Static and Dynamic Crack Propagation in Brittle Materials with XFEM written by Fleming Petri, Wagner Carlos and published by kassel university press GmbH. This book was released on 2013-01-01 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this thesis is the simulation of progressive damage in brittle materials due to cracking. With this aim, the mathematical crack model will be solved using the eXtended Finite Element Method for the spatial discretization and time integration schemes for the numerical integration in the time domain. The time integration schemes considered are the Generalized-? method, the continuous GALERKIN method and the discontinuous GALERKIN method.
Book Synopsis Dynamic Crack Propagation in Brittle Materials by : Jozef Cornelis Walterus van Vroonhoven
Download or read book Dynamic Crack Propagation in Brittle Materials written by Jozef Cornelis Walterus van Vroonhoven and published by . This book was released on 1996 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fracture Simulations of Brittle Materials Using Cohesive Elements by : Chin-Hang Sam
Download or read book Fracture Simulations of Brittle Materials Using Cohesive Elements written by Chin-Hang Sam and published by . This book was released on 2003 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fracture and Damage in Quasibrittle Structures by : Z.P. Bazant
Download or read book Fracture and Damage in Quasibrittle Structures written by Z.P. Bazant and published by CRC Press. This book was released on 2004-01-14 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Modeling Mixed-mode Dynamic Crack Propagation Using Finite Elements by : Daniel Vernon Swenson
Download or read book Modeling Mixed-mode Dynamic Crack Propagation Using Finite Elements written by Daniel Vernon Swenson and published by . This book was released on 1986 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mixed-mode Dynamic Crack Propagation Using the Discontinuous Galerkin Method by : Russell Thomas Hollman
Download or read book Mixed-mode Dynamic Crack Propagation Using the Discontinuous Galerkin Method written by Russell Thomas Hollman and published by . This book was released on 2017 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: A recently proposed Discontinuous Galerkin (DG) method for modeling nonlinear fracture mechanics problems in the context of the finite element method is investigated. The DG method provides a framework for fracture mechanics by employing interface elements within the region of interest where cracking is expected. Previous studies have shown that the use of traction-separation laws within the DG method have enhanced stability for dynamic problems by removing the issue of artificial compliance compared to intrinsic cohesive zone elements. The purpose of this thesis is to apply the DG method to a mixed-mode dynamic crack propagation problem, namely the Kalthoff-Winkler experiment. The Kalthoff-Winkler experiment is a benchmark dynamic fracture problem for predicting crack propagation in an impact-loaded prenotched plate. While this problem has been simulated using other numerical methods, the DG method has not yet been investigated in this mixed-mode dynamic context. Mesh sensitivity has been found in the case of intrinsic cohesive zone models; the inherent stability of the DG method in the dynamic context may lessen the degree of sensitivity. The DG method is applied to the Kalthoff-Winkler experiment using multiple meshes: structured and unstructured, linear and quadratic, coarse and refined, and the resultant crack paths from several simulations do not agree closely. An additional contribution of this thesis is a novel technique for visualizing cohesive element data through wireframe figures. The technique produces illustrations for visualizing zero-thickness interface elements as thin lines, upon which cohesive element data can be conveyed with color contouring. Possible explanations regarding the disagreement of simulated crack paths are suggested.
Book Synopsis Isogeometric Analysis of Phase-field Models for Dynamic Brittle and Ductile Fracture by : Michael Johns Borden
Download or read book Isogeometric Analysis of Phase-field Models for Dynamic Brittle and Ductile Fracture written by Michael Johns Borden and published by . This book was released on 2012 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: To date, efforts to model fracture and crack propagation have focused on two broad approaches: discrete and continuum damage descriptions. The discrete approach incorporates a discontinuity into the displacement field that must be tracked and updated. Examples of this approach include XFEM, element deletion, and cohesive zone models. The continuum damage, or smeared crack, approach incorporates a damage parameter into the model that controls the strength of the material. An advantage of this approach is that it does not require interface tracking since the damage parameter varies continuously over the domain. An alternative approach is to use a phase-field to describe crack propagation. In the phase-field approach to modeling fracture the problem is reformulated in terms of a coupled system of partial differential equations. A continuous scalar-valued phase-field is introduced into the model to indicate whether the material is in the unfractured or fractured ''phase''. The evolution of the phase-field is governed by a partial differential equation that includes a driving force that is a function of the strain energy of the body in question. This leads to a coupling between the momentum equation and the phase-field equation. The phase-field model also includes a length scale parameter that controls the width of the smooth approximation to the discrete crack. This allows discrete cracks to be modeled down to any desired length scale. Thus, this approach incorporates the strengths of both the discrete and continuum damage models, i.e., accurate modeling of individual cracks with no interface tracking. The research presented in this dissertation focuses on developing phase-field models for dynamic fracture. A general formulation in terms of the usual balance laws supplemented by a microforce balance law governing the evolution of the phase-field is derived. From this formulation, small-strain brittle and large-deformation ductile models are then derived. Additionally, a fourth-order theory for the phase-field approximation of the crack path is postulated. Convergence and approximation results are obtained for the proposed theories. In this work, isogeometric analysis, and particularly T-splines, plays an important role by providing a smooth basis that allows local refinement. Several numerical simulations have been performed to evaluate the proposed theories. These results show that phase-field models are a powerful tool for predicting fracture.
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.
Book Synopsis A Stochastic Continuum Damage Model for Dynamic Fracture Analysis of Quasi-brittle Materials Using Asynchronous Spacetime Discontinuous Galerkin (aSDG) Method by : Bahador Bahmani
Download or read book A Stochastic Continuum Damage Model for Dynamic Fracture Analysis of Quasi-brittle Materials Using Asynchronous Spacetime Discontinuous Galerkin (aSDG) Method written by Bahador Bahmani and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The microstructural design has an essential effect on the fracture response of brittle materials. We present a stochastic bulk damage formulation to model dynamic brittle fracture. This model is compared with a similar interfacial model for homogeneous and heterogeneous materials. The damage models are rate-dependent, and the corresponding damage evolution includes delay effects. The evolution equation specifies the rate at which damage tends to its quasi-static limit. The relaxation time of the model introduces an intrinsic length scale for dynamic fracture and addresses the mesh sensitivity problem of earlier damage models with much less computational efforts. The ordinary differential form of the damage equation makes this remedy quite simple and enables capturing the loading rate sensitivity of strain-stress response. A stochastic field is defined for material cohesion and fracture strength to involve microstructure effects in the proposed formulations. The statistical fields are constructed through the Karhunen-Loeve (KL) method. An advanced asynchronous Spacetime Discontinuous Galerkin (aSDG) method is used to discretize the final system of coupled equations. Local and asynchronous solution process, linear complexity of the solution versus the number of elements, local recovery of balance properties, and high spatial and temporal orders of accuracy are some of the main advantages of the aSDG method. Several numerical examples are presented to demonstrate mesh insensitivity of the method and the effect of boundary conditions on dynamic fracture patterns. It is shown that inhomogeneity greatly differentiates fracture patterns from those of a homogeneous rock, including the location of zones with maximum damage. Moreover, as the correlation length of the random field decreases, fracture patterns resemble angled-cracks observed in compressive rock fracture. The final results show that a stochastic bulk damage model produces more realistic results in comparison with a homogenizes model.
Book Synopsis Fracture of Engineering Brittle Materials by : Ayal de S. Jayatilaka
Download or read book Fracture of Engineering Brittle Materials written by Ayal de S. Jayatilaka and published by . This book was released on 1979 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Life of Cracks by : Srečko Glodež
Download or read book The Life of Cracks written by Srečko Glodež and published by Cambridge Scholars Publishing. This book was released on 2020-07-13 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many people find the concept of fracture and damage mechanics to be somewhat problematic, mainly because, until recently, close attention in mechanics was focused especially on the strength and resistance of materials. In this sense, to speak of fracture is as uncomfortable for some as it is to speak of a deadly disease. In confronting and preventing a fatal disease, one must understand its complexity, symptoms, and behavior; by the same token, in securing the strength of an engineering structure, one must understand the reasons and type of its potential failure. This book will provide knowledge and insights on this matter to its readers.
Book Synopsis Discontinuous Galerkin Methods for Elasticity and Crack Propagation Problems by : Aurelio Arranz Carreno
Download or read book Discontinuous Galerkin Methods for Elasticity and Crack Propagation Problems written by Aurelio Arranz Carreno and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new set of numerical methods for predictive modelling of quasistatic and dynamic crack propagation in brittle materials for aerospace applications based upon the Symmetric Interior Penalty Galerkin Method (SIPG) and the Nonsymmetric Interior Penalty Galerkin Method (NIPG) is proposed. This new approach to solving problems in Computational Fracture Mechanics belongs to the family of Discontinuous Galerkin Finite Element Meth- ods (DGFEMs) and draws on the qualities of both the classical Finite Element Methods (FEMs) and Finite Volume Methods (FVMs) in order to overcome the shortcomings and limitations which both methods exhibit when trying to address the transition from contin- uum to discontinuum during material fracture. This thesis focuses mainly on the numerical linear algebra aspects associated with the two above DGFEM methods when applied to crack propagation problems. A new precondi- tioning technique for the iterative solution of linear systems of equations is introduced and its qualities are presented by means of numerical examples. A coupling technique with pre- conditioners for conforming approximations is also introduced. Several improvements and extensions to the original technique are presented to make crack propagation simulations with the SIPG viable. Results for both quasistatic and dynamic fracture propagation are presented. Practical aspects ofthe implementation are also discussed, revealing the important issues that still have to be addressed and that constitute paths for further research.
Book Synopsis Dynamic Brittle Fracture Analysis Based on Continuum Damage Mechanics by : E-P Chen
Download or read book Dynamic Brittle Fracture Analysis Based on Continuum Damage Mechanics written by E-P Chen and published by . This book was released on 1989 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dynamic response of materials with existing flaw structures is the subject of the present investigation. In this paper, the cracked solid is described by a constitutive model based on continuum damage mechanics. The purpose of the analysis is to show that the constitutive model can predict many of the experimentally observed phenomena in these materials. This is demonstrated by treating a sample problem. The geometry and loading condition selected for this sample problem is that of a 45-deg inclined crack, centrally situated in a concrete panel and subjected to the action of a step tensile pulse. Damage localization and tension-softening have been observed. These results and their implications are discussed.
Book Synopsis Three-Dimensional Gear Crack Propagation Studies by :
Download or read book Three-Dimensional Gear Crack Propagation Studies written by and published by . This book was released on 1998 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional crack growth simulation was performed on a split-tooth gear design using boundary element modeling and linear elastic fracture mechanics. Initial cracks in the fillet of the teeth produced stress intensity factors of greater magnitude (and thus, greater crack growth rates) than those in the root or groove areas of the teeth. Crack growth simulation was performed on a case study to evaluate crack propagation paths. Tooth fracture was predicted from the crack growth simulation for an initial crack in the tooth fillet region. Tooth loads on the uncracked mesh of the split-tooth design were up to five times greater than those on the cracked mesh if equal deflections of the cracked and uncracked teeth were considered. Predicted crack shapes as well as crack propagation life are presented based on calculated stress intensity factors, mixed-mode crack propagation trajectory theories, and fatigue crack growth theories.
