Download or read book Gradient Effects on the Fracture of Inhomogeneous Materials written by Terrence Lee Becker and published by . This book was released on 2000 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gradient Effects on the Fracture of Inhomogeneous Materials written by and published by . This book was released on 2000 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: Functionally Graded Materials (FGMs) have a spatial variation in physical properties that can be tailored to meet the needs of a specific application and/or to minimize internal stresses arising from thermal and elastic mismatch. Modeling these materials as inhomogeneous continua allows assessment of the role of the gradient without requiring detailed knowledge of the microstructure. Motivated by the relative difficulty of obtaining analytical solutions to boundary value problems for FGMs, an accurate finite-element code is developed for obtaining numerical planar and axisymmetric linear thermoelastic solutions. In addition an approximate analytical technique for mapping homogeneous-modulus solutions to those for FGMs is assessed and classes of problems to which it applies accurately are identified. The fracture mechanics analysis of FGMs can be characterized by the classic stress intensities, KI and KII, but there has been scarce progress in understanding the role of the modulus gradient in determining fracture initiation and propagation. To address this question, a statistical fracture model is used to correlate near-tip stresses with brittle fracture initiation behavior. This describes the behavior of a material experiencing fracture initiation away from the crack tip. Widely dispersed zones of fracture initiation sites are expected. Finite-length kinks are analyzed to describe the crack path for continuous crack growth. For kink lengths much shorter than the gradient dimension, a parallel stress term describes the deviation of the kinking angle from that for homogeneous materials. For longer kinks there is a divergence of the kink angle predicted by the maximum energy release rate and the pure opening mode criteria.
Download or read book Gradient Effects in Inhomogeneous Plastic Flow and Fracture Behavior of Single Crystals written by Huang Tang and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Micromechanisms of Fracture and Fatigue written by Jaroslav Pokluda and published by Springer Science & Business Media. This book was released on 2010-05-27 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micromechanisms of Fracture and Fatigue forms the culmination of 20 years of research in the field of fatigue and fracture. It discusses a range of topics and comments on the state of the art for each. The first part is devoted to models of deformation and fracture of perfect crystals. Using various atomistic methods, the theoretical strength of solids under simple and complex loading is calculated for a wide range of elements and compounds, and compared with experimental data. The connection between the onset of local plasticity in nanoindentation tests and the ideal shear strength is analysed using a multi-scale approach. Moreover, the nature of intrinsic brittleness or ductility of perfect crystal lattices is demonstrated by the coupling of atomistic and mesoscopic approaches, and compared with brittle/ductile behaviour of engineering materials. The second part addresses extrinsic sources of fracture toughness of engineering materials, related to their microstructure and microstructurally-induced crack tortuosity. Micromechanisms of ductile fracture are also described, in relation to the fracture strain of materials. Results of multilevel modelling, including statistical aspects of microstructure, are used to explain remarkable phenomena discovered in experiments. In the third part of the book, basic micromechanisms of fatigue cracks propagation under uniaxial and multiaxial loading are discussed on the basis of the unified mesoscopic model of crack tip shielding and closure, taking both microstructure and statistical effects into account. Applications to failure analysis are also outlined, and an attempt is made to distinguish intrinsic and extrinsic sources of materials resistance to fracture. Micromechanisms of Fracture and Fatigue provides scientists, researchers and postgraduate students with not only a deep insight into basic micromechanisms of fracture behaviour of materials, but also a number of engineering applications.
Download or read book Advances in Functionally Graded Materials and Structures written by Farzad Ebrahimi and published by BoD – Books on Demand. This book was released on 2016-03-31 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Functionally graded materials (FGMs) were initially designed as thermal barrier materials for aerospace structures and fusion reactors and now they are also considered as potential structural materials for future high-speed spacecraft and recently are being increasingly considered in various applications to maximize strengths and integrities of many engineering structures. This book is a result of contributions of experts from international scientific community working in different aspects of FGMs and structures and reports on the state of the art research and development findings on this topic through original and innovative research studies. Through its six chapters the reader will have access to works related to processing, sintering properties and applications of functionally graded ceramics and new processing routes for FGMs while it introduces some specific applications, such as functionally graded annular fins and the high-performance self-lubricating ceramic composites with laminated graded structure. Besides, it presents an experimental crack propagation analysis of aluminum matrix FGMs and a unified accurate solution for three-dimensional vibration analysis of functionally graded plates and cylindrical shells with general boundary conditions.
Download or read book Fatigue and Fracture Mechanices written by Steven R. Daniewicz and published by ASTM International. This book was released on 2005-09 with total page 591 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Stress Concentration on the Fracture and Deformation Characteristics of Ceramics and Metals written by Volker Weiss and published by . This book was released on 1963 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of non-uniform stress distributions on fracture strength were studied on four mate rials that exhibit brittle behavior; Wesgo AL995, Mykroy 750 and 1100 (ceramics) and Plexiglas (acrylic plastic). Analysis of the results of both notch tensile and bend tests on these materials indicate that fracture in ceramic materials can be explained by a maximum fracture stress concept provided that the inherent inhomogeneity of these materials is considered in the analysis. Weibull's statistical theory of fracture appears to be ap plicable to the analysis of inhomogeneity. The be havior of Plexiglas is similar to that previously observed for high strength metals. Studies of plastic flow in metallic flat notch tensile speci mens indicate that the distribution of the princi pal longitudinal strain across the notch section is related to the distribution of the longitudinal elastic stress raised to the power b, where b is primarily a function of the strain hardening ex ponent of the material. Also, Neuber's conclusion that K sub t represents the geometric mean of the true stress and true strain concentration factors in pure shear seems generally applicable to the plane stress tension case.
Download or read book Fracture Mechanics for Materials with Strain Gradient Effects written by Jiyu Chen and published by . This book was released on 1998 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Notch Effects in Fatigue and Fracture written by G. Pluvinage and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: As Directors of this NATO Workshop, we welcome this opportunity to record formally our thanks to the NATO Scientific Affairs Division for making our meeting possible through generous financial support and encouragement. This meeting has two purposes: the first obvious one because we have collected scientists from East, far East and west to discuss new development in the field of fracture mechanics: the notch fracture mechanics. The second is less obvious but perhaps in longer term more important that is the building of bridges between scientists in the frame of a network called Without Walls Institute on Notch Effects in Fatigue and Fracture". Physical perception of notch effects is not so easy to understand as the presence of a geometrical discontinuity as a worst effect than the simple reduction of cross section. Notch effects in fatigue and fracture is characterised by the following fundamental fact: it is not the maximum local stress or stress which governs the phenomena of fatigue and fracture. The physic shows that a process volume is needed probably to store the necessary energy for starting and propagating the phenomenon. This is a rupture of the traditional "strength of material" school which always give the prior importance of the local maximum stress. This concept of process volume was strongly affirmed during this workshop.
Download or read book Fracture of Functionally Graded Materials written by G.H. Paulino and published by Elsevier. This book was released on 2002-10-23 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientific research on functionally graded materials (FGM's) looks at functions of gradients in materials comprising thermodynamic, mechanical, chemical, optical, electromagnetic, and/or biological aspects. This collection of technical papers represents current research interests with regard to the fracture behaviour of FGM's. The papers provide a balance between theoretical, computational, and experimental techniques. It also indicates areas for increased development, such as constraint effects, full experimental characterization of engineering FGM's under static and dynamic loading, development of fracture criteria with predictive capability, multiphysics and multiscale failure considerations, and connection of research with industrial applications.
Download or read book Lectures Notes on Advanced Structured Materials 2 written by Holm Altenbach and published by Springer Nature. This book was released on with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamic Fracture of Piezoelectric Materials written by Petia Dineva and published by Springer Science & Business Media. This book was released on 2014-01-30 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic Fracture of Piezoelectric Materials focuses on the Boundary Integral Equation Method as an efficient computational tool. The presentation of the theoretical basis of piezoelectricity is followed by sections on fundamental solutions and the numerical realization of the boundary value problems. Two major parts of the book are devoted to the solution of problems in homogeneous and inhomogeneous solids. The book includes contributions on coupled electro-mechanical models, computational methods, its validation and the simulation results, which reveal different effects useful for engineering design and practice. The book is self-contained and well-illustrated, and it serves as a graduate-level textbook or as extra reading material for students and researchers.
Download or read book The Effect of Stress Gradient and Stress Biaxiality on the Behavior of Materials written by Volker Weiss and published by . This book was released on 1962 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Effects of stress gradient and stress biaxiality on the notch strength of brittle, semi-brittle and semi-ductile materials were investigated. Results obtained on a nearly ideally brittle titanium alloy are in agreement with the predictions of a fracture concept based on Neuber's theory of notch stresses. Accordingly, the stress concentration factor is the dominant parameter. The magnitude of the stress gradient and stress biaxiality at the notch root has a secondary effect in that the notch strength of brittle materials is reduced with decreasing gradient and increasing biaxiality. The notch strength behavior of brittle ceramics has to be interpreted in terms of the inhomogeneity of these materials. Weibull's statistical theory of fracture was applied to this problem. Semi-brittle and semi-ductile materials exhibit a behavior similar in trend to that predicted for brittle materials with respect to stress concentration factor, stress gradient and stress biaxiality. However, for low stress concentration factor values, these effects are altered by phenomena due to plastic deformation at and near the notch root which significantly modify the stress and strain distribution and cause notch strengthening, the amount of which in itself appears related to the stress gradient and the stress biaxiality.
Download or read book Fracture of Nonmetals and Composites written by H. Liebowitz and published by Elsevier. This book was released on 2013-10-22 with total page 1067 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture: An Advanced Treatise, Volume VII: Fracture of Nonmetals and Composites examines the fracture of nonmetals and composites. The text of this treatise has been designed so that the reader may acquire pertinent information by self-study. Most chapters have been written in detail and, insofar as possible, have been made to fill a significant gap by also providing, when appropriate, the details of complicated and involved mathematical derivations in appendixes. Whenever possible, only a level of college calculus on the part of the reader has been assumed. Numerical examples showing the engineering applications have been included; also, photographs and drawings have been greatly utilized. The book opens with a review of the fracture behavior of glass. This is followed by separate chapters on the fracture of polymeric glasses; mechanics of the fracture process in rock, with emphasis on the engineering viewpoint; the fracture behavior of simple, single-phase ceramics; and empirical information about, and our level of understanding of, fracture in polycrystalline ceramics. Subsequent chapters deal with the fracture of elastomers; molecular mechanical aspects of the isothermal rupture of elastomers; failure mechanics of fibrous composites; fracture mechanics of composites; fracture and healing of compact bones; and fracture of two-phase alloys; and fracture of lake ice and sea ice.
Download or read book Superalloys 2024 written by Jonathan Cormier and published by Springer Nature. This book was released on with total page 1121 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shallow Crack Fracture Mechanics Toughness Tests and Applications written by Michael Graham Dawes and published by Woodhead Publishing. This book was released on 1992-01-15 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the last decade there has been an increasing awareness that use of standards deeply notched fracture mechanics test specimens can result in substantial over-or-under-assessments of the real fracture toughness associated with shallow surface cracks.
Download or read book NASA Conference Publication written by and published by . This book was released on 1993 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
