Download or read book Coupled Thermal Stress Simulations of Ductile Tearing written by and published by . This book was released on 2016 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Predictions for ductile tearing of a geometrically complex Ti-6Al-4V plate were generated using a Unified Creep Plasticity Damage model in fully coupled thermal stress simulations. Uniaxial tension and butterfly shear tests performed at displacement rates of 0.0254 and 25.4 mm/s were also simulated. Results from these simulations revealed that the material temperature increase due to plastic work can have a dramatic effect on material ductility predictions in materials that exhibit little strain hardening. Furthermore, this occurs because the temperature increase causes the apparent hardening of the material to decrease which leads to the initiation of deformation localization and subsequent ductile tearing earlier in the loading process.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Challenges in Mechanics of Time Dependent Materials and Processes in Conventional and Multifunctional Materials Volume 2 written by Bonnie Antoun and published by Springer Science & Business Media. This book was released on 2012-11-09 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Challenges in Mechanics of Time-Dependent Materials and Processes in Conventional and Multifunctional Materials, Volume 2 represents one of seven volumes of technical papers presented at the Society for Experimental Mechanics SEM 12th International Congress & Exposition on Experimental and Applied Mechanics, held at Costa Mesa, California, June 11-14, 2012. The full set of proceedings also includes volumes on: Dynamic Behavior of Materials, Imaging Methods for Novel Materials and Challenging Applications, Experimental and Applied Mechanics, 2nd International Symposium on the Mechanics of Biological Systems and Materials 13th International Symposium on MEMS and Nanotechnology and, Composite Materials and the 1st International Symposium on Joining Technologies for Composites.

Download or read book Modeling of the Damage Mechanisms in AlMgSi Alloys written by Denis Lassance and published by Presses univ. de Louvain. This book was released on 2006 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the growth in importance of the aluminium industry, has come increased demand to invest into the quality improvement of the different aluminium based hot extruded products. One of the main mechanisms, which can influence deformation at high temperature within the 6xxx aluminium, is linked to the presence of the AlFeSi intermetallic phases. These phases severely restrict hot workability when present as hard and brittle plate-like precipitates b-AlFeSi. Damage initiation occurs in these alloys by decohesion or fracture of these intermetallic inclusions. The understanding and modeling of the deformation and fracture behavior of aluminium alloys at room and at hot working temperature is very important for optimizing manufacturing processes such as extrusion. The ductility of 6xxx aluminium alloys can be directly related to chemical composition and to the microstructural evolution occurring during the heat treatment procedures preceding extrusion if proper physics based deformation and fracture models are used. In this thesis, room temperature and hot tensile tests are adopted to address the problem xperimentally. The damage evolution mechanisms is defined at various temperatures and a micromechanics based model of the Gurson type considering several populations of cavities nucleated by different second phase particles groups is developed on the basis of the experimental observations. This model allows relating quantitatively microstructure and ductility at various temperatures strain rates and stress triaxialities. Finite element simulations based on an enhanced micromechanics-based model are used to validate the model. Finally, the effect of some key factors that determine the extrudability of aluminium is also discussed and a correlation between the ductility calculations in uniaxial tension and the maximum extrusion speed is developed for one defined profile.

Download or read book Proceedings of the 8th International Conference on Fracture Fatigue and Wear written by Magd Abdel Wahab and published by Springer Nature. This book was released on 2021-01-12 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings gather a selection of peer-reviewed papers presented at the 8th International Conference on Fracture Fatigue and Wear (FFW 2020), held as a virtual conference on 26–27 August 2020. The contributions, prepared by international scientists and engineers, cover the latest advances in and innovative applications of fracture mechanics, fatigue of materials, tribology, and wear of materials. In addition, they discuss industrial applications and cover theoretical and analytical methods, numerical simulations and experimental techniques. The book is intended for academics, including graduate students and researchers, as well as industrial practitioners working in the areas of fracture fatigue and wear.

Download or read book From Charpy to Present Impact Testing written by D. Francois and published by Elsevier. This book was released on 2002-06-18 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: From Charpy to Present Impact Testing contains 52 peer-reviewed papers selected from those presented at the Charpy Centenary Conference held in Poitiers, France, 2-5 October 2001. The name of Charpy remains associated with impact testing on notched specimens. At a time when many steam engines exploded, engineers were preoccupied with studying the resistance of steels to impact loading. The Charpy test has provided invaluable indications on the impact properties of materials. It revealed the brittle ductile transition of ferritic steels. The Charpy test is able to provide more quantitative results by instrumenting the striker, which allows the evolution of the applied load during the impact to be determined. The Charpy test is of great importance to evaluate the embrittlement of steels by irradiation in nuclear reactors. Progress in computer programming has allowed for a computer model of the test to be developed; a difficult task in view of its dynamic, three dimensional, adiabatic nature. Together with precise observations of the processes of fracture, this opens the possibility of transferring quantitatively the results of Charpy tests to real components. This test has also been extended to materials other than steels, and is also frequently used to test polymeric materials. Thus the Charpy test is a tool of great importance and is still at the root of a number of investigations; this is the reason why it was felt that the centenary of the Charpy test had to be celebrated. The Société Française de Métallurgie et de Matériaux decided to organise an international conference which was put under the auspices of the European Society for the Integrity of Structures (ESIS). This Charpy Centenary Conference (CCC 2001) was held in Poitiers, at Futuroscope in October 2001. More than 150 participants from 17 countries took part in the discussions and about one hundred presentations were given. An exhibition of equipment showed, not only present day testing machines, but also one of the first Charpy pendulums, brought all the way from Imperial College in London. From Charpy to Present Impact Testing puts together a number of significant contributions. They are classified into 6 headings: •Keynote lectures,•Micromechanisms,•Polymers,•Testing procedures,•Applications,•Modelling.

Download or read book Coupled Interactions Between the Seismogenic Zone and the Ductile Root of Faults written by Kali L. Allison and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on understanding the interaction between the seismogenic zone of strike-slip faults and their ductile roots, and resulting implications for the structure and dynamics of the continental lithosphere in which they are embedded. A wide range of observations highlight the significance of this interaction, including the time- and depth-dependence of transient postseismic deformation (both frictional afterslip and bulk viscous flow), the triggering of aftershocks by viscous flow, the spatiotemporal distribution of microseismicity, and microstructural data from exhumed faults. Furthermore, the depth-extent of large strike-slip earthquakes appears to be limited to the mid-crust, resulting from a transition in deformation style or material properties in the middle and to lower crust. Previous work has demonstrated by increasing temperature with depth in the crust causes two significant transitions: a transition in frictional properties on the fault from velocity-weakening (VW) to velocity-strengthening (VS), and a transition in off-fault deformation from brittle deformation to crystal-plastic creep (the brittle-ductile transition, or BDT). Both of these transitions are estimated to occur roughly at 10-20~km depth, and therefore both are candidates for control over the nucleation depth of large earthquakes and their downdip propagation limit, and therefore control over an upper bound on the largest earthquake possible on a strike-slip fault. As both transitions are temperature-dependent, the effects of heat generation through frictional and viscous shear heating will impact the structure and dynamics of the system, possibly producing a shallow BDT and smaller earthquakes. This work is performed in the context of earthquake cycle simulations, in which all phases of the earthquake cycle are modeled. In the interseismic period, slow tectonic loading causes a stress concentration to build up on the fault, which spontaneously nucleates each earthquake. The propagation of the rupture up and down the fault is then simulated, and finally the postseismic period is simulated as well. These simulations allow the slip, stress drop, and recurrence interval of each earthquake to develop in a way that is self-consistent with the history of earthquakes and postseismic deformation. Previous earthquake cycle work has generally focused on either the frictional transition on the fault or the transition from brittle to ductile deformation. Simulations which take the first approach simulate rate-and-state friction on the fault, representing the off-fault material as linear elastic, and are able to explore a rich variety of event types and sizes, including large and small earthquakes and slow slip events. They are also able to reproduce a number of observations, including: the general time scale of each phase of the earthquake cycle, the depth-extent of the seismogenic zone, and the signature of frictional afterslip in surface deformation. Other work, which takes the second approach, models the off-fault material with a thermally activated creep law, but kinematically imposes the earthquakes. These studies are able to explore the structure of the shear zones beneath faults, the time-dependence of the effective viscosity, and the effects of viscous shear heating. A few recent studies have included both transitions simultaneously, and have been able to reproduce observations of elevated bulk viscous flow in the postseismic period and the existence of a region of both coseismic slip and bulk viscous flow. My work fits into this last category, and I focus on the interaction between rate-and-state friction and viscoelastic material in the lower crust and upper mantle. In this thesis, I develop a thermomechanical finite difference code which is able to simulate earthquake cycles with the fault described by rate-and-state friction and viscoelastic off-fault material represented with a nonlinear power-law rheology, including both frictional and viscous shear heating. The primary focus is on representing the BDT as a broad transition zone whose depth is not imposed a priori, but rather results from the solution of the system of governing equations. The philosophy is to start with the simplest case that combines spontaneously nucleating earthquakes with bulk viscous flow. As a result these simulations are performed in antiplane strain in two-dimensions, with a vertical strike-slip fault. I also use the quasidynamic approximation in the first two chapters, an approximation which makes the development of the numerical method simpler by neglecting wave-mediated stress transfer. In the first chapter of the thesis, I perform viscoelastic cycle simulations. I consider a range of background geotherms, and find that this produces qualitatively different deformation styles in the lower crust and upper mantle, ranging from significant fault creep at depth in the coolest model to purely bulk viscous flow in the warmest model. The simulations presented in this study encompass the range of effective viscosity estimates for the Wester US from deformation studies, indicating that the effective viscosity estimates imply a great deal of uncertainty in the predominant deformation mechanism of the lower crust. Later in the thesis, I incorporate a method for the simulation of fully dynamic ruptures in the coseismic period into the viscoelastic cycle simulation code. I also explore criteria for switching from the quasidynamic method in the interseismic period to the fully dynamic method in the coseismic period and back, based on the magnitude of the radiation damping term relative to the quasi-static shear stress. In the next part of the thesis, I extend this work to include frictional and viscous shear heating, which produces elevated temperature (or thermal anomaly relative to the background geotherm) near the fault. This reduces the effective viscosity in this region, resulting in a shallower BDT and, in some parts of parameter space, reducing the depth of earthquake nucleation and the downdip limit of coseismic slip. One significant finding of this work is that frictional and viscous shear heating both contribute roughly equally to this thermal anomaly. Part of this work was the development of a steady-state approximation to the system, in which the viscous strain rates and slip velocity are constant. I find that this steady-state approximation well-characterizes the depth of the BDT and magnitude of the cycle-average thermal anomaly.

Download or read book Thermomechanical Industrial Processes written by Jean-Michel Bergheau and published by John Wiley & Sons. This book was released on 2014-02-19 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: The numerical simulation of manufacturing processes and of their mechanical consequences is of growing interest in industry. However, such simulations need the modeling of couplings between several physical phenomena such as heat transfer, material transformations and solid or fluid mechanics, as well as to be adapted to numerical methodologies. This book gathers a state of the art on how to simulate industrial processes, what data are needed and what numerical simulation can bring. Assembling processes such as welding and friction stir welding, material removal processes, elaboration processes of composite structures, sintering processes, surface-finishing techniques, and thermo-chemical treatments are investigated. This book is the work of a group of researchers who have been working together in this field for more than 12 years. It should prove useful for both those working in industry and those studying the numerical methods applied to multiphysics problems encountered in manufacturing processes.

Download or read book Introduction to Texture Analysis written by Olaf Engler and published by CRC Press. This book was released on 2009-11-16 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first edition of Introduction to Texture Analysis: Macrotexture, Microtexture, and Orientation Mapping broke new ground by collating seventy years worth of research in a convenient single-source format. Reflecting emerging methods and the evolution of the field, the second edition continues to provide comprehensive coverage of the concepts, pra

Download or read book Earthquakes Simulations Sources and Tsunamis written by Kristy F. Tiampo and published by Springer Science & Business Media. This book was released on 2008-11-04 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume attempts to present the current state of seismic research by focusing not only on the modeling of earthquakes and earthquake generated tsunamis, but also on practical comparisons of the resulting phenomenology. In the 1990s, major advancements in seismic research greatly added to the understanding of earthquake fault systems as complex dynamical systems. Large quantities of new and extensive remote sensing data sets provided information on the solid earth.

Download or read book Modeling of Material Damage and Failure of Structures written by Jacek J. Skrzypek and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extensive and comprehensive survey of one- and three-dimensional damage models for elastic and inelastic solids. The book not only provides a rich current source of knowledge, but also describes examples of practical applications, numerical procedures, and computer codes. The style throughout is systematic, clear, and concise, and supported by illustrative diagrams. The state of the art is given by some 200 references.

Download or read book Creep and Fracture in High Temperature Components written by European Creep Collaborative Committee and published by DEStech Publications, Inc. This book was released on 2005 with total page 1136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides information from around the world on creep in multiple high-temperature metals, alloys, and advanced materials.

Download or read book Modeling High Temperature Materials Behavior for Structural Analysis written by Konstantin Naumenko and published by Springer. This book was released on 2016-05-11 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents approaches to characterize inelastic behavior of materials and structures at high temperature. Starting from experimental observations, it discusses basic features of inelastic phenomena including creep, plasticity, relaxation, low cycle and thermal fatigue. The authors formulate constitutive equations to describe the inelastic response for the given states of stress and microstructure. They introduce evolution equations to capture hardening, recovery, softening, ageing and damage processes. Principles of continuum mechanics and thermodynamics are presented to provide a framework for the modeling materials behavior with the aim of structural analysis of high-temperature engineering components.

Download or read book British Welding Journal written by and published by . This book was released on 1954 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1979 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Modeling of Materials Under Extreme Conditions written by Nicola Bonora and published by Springer. This book was released on 2014-05-09 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents twelve state of the art contributions in the field of numerical modeling of materials subjected to large strain, high strain rates, large pressure and high stress triaxialities, organized into two sections. The first part is focused on high strain rate-high pressures such as those occurring in impact dynamics and shock compression related phenomena, dealing with material response identification, advanced modeling incorporating microstructure and damage, stress waves propagation in solids and structures response under impact. The latter part is focused on large strain-low strain rates applications such as those occurring in technological material processing, dealing with microstructure and texture evolution, material response at elevated temperatures, structural behavior under large strain and multi axial state of stress.

Download or read book Fatigue and Fracture 1996 written by and published by . This book was released on 1996 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second of two volumes on the subject containing papers from a symposium of the July 1996 meeting. Thirty papers are arranged in four sections on new areas of fracture mechanics; material fracture toughness; failure assessment diagram method user experience (with four application-type papers); an