Download or read book Computational Investigation of Local Material Strength and Toughness on Crack Growth written by V. G. DeGiorgi and published by . This book was released on 1990 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational simulation of stable crack growth is an important aspect of structural integrity prediction. Modern alloy strength and ductility increase local material fracture toughness but simultaneously complicates stable crack growth predictions. Material modeling, material parameter identification, fracture criterion and numerical crack growth algorithms are issues which must be addressed for robust stable crack growth prediction. In this investigation, a series of finite element simulations were undertaken to investigate two-dimensional Mode I crack growth in a modified compact tension specimen geometry. Two different crack lengths were considered. HY-100 steel parameters, previously characterized for large strain deformation, were utilized. Additional material responses, based on the HY-100 nonlinear response but with different yield strengths and ductilities, were also considered to parametrically assess material effects on crack growth. (JES).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

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 Materials Science and Engineering at the Naval Research Laboratory written by Naval Research Laboratory (U.S.) and published by . This book was released on with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Techniques for Materials Composites and Composite Structures written by B. H. V. Topping and published by . This book was released on 2000 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contains a selection of papers that were presented at The Fifth International Conference on Computational Structures Technology and The Second International Conference on Engineering Computational Technology, which were held in Leuven, Belgium from 6-8 September 2000.

Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue and Fracture Mechanics written by Ravinder Chona and published by ASTM International. This book was released on 2002 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1994 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Tech Briefs written by and published by . This book was released on 1988 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue and Fracture Mechanics written by Tina Louise Panontin and published by ASTM International. This book was released on 1999 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metals Abstracts written by and published by . This book was released on 1998 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Fatique and Fracture Mechanics written by Gary R. Halford and published by ASTM International. This book was released on 2000 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metals Abstracts Index written by and published by . This book was released on 1996 with total page 1622 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Steady Crack Growth Through Ductile Metals Computational Studies written by James C. Sobotka and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines the crack-front response during sustained ductile tearing in structural metals at quasi-static rates using high resolution finite element computations. At load levels approaching the steady-growth regime, well-established computational methods that model material damage break down numerically as vanishingly small load increments produce increasingly large amounts of crack extension. The computational model adopted here determines the deformation history of a steadily advancing crack directly without the need for a priori (transient) analysis that considers blunting of the pre-existing stationary crack and subsequent growth through the associated initial plastic zone. Crack extension occurs at the remotely applied, fixed loading without the need for a local growth criteria. This numerical scheme utilizes a streamline integration technique to determine the elastic-plastic fields, generalized from a two-dimensional to a fully three-dimensional setting and implemented within mixed Matlab/C++/F-90 based software. Modifications of the conventional finite element formulation lead to an efficient procedure -- readily parallelized -- and determine the invariant near-front fields, representative of steady-state growth, on a fixed mesh in a boundary-layer framework. In the small-scale yielding regime, the crack front does not sense the existence of remote boundaries, and computational results retain a strong transferability among various geometric configurations where near-front, plastic deformation remains entirely enclosed by the surrounding linear-elastic material. The global stress intensity factor (KI) and imposed T-stress fully specify displacement constraints along the far-field boundary, and in a three-dimensional setting, the panel thickness reflects the only natural length scale. The initial studies in this work consider steady crack advance within the small-scale yielding context under plane-strain conditions and mode I loading. These analyses focus on steady crack growth within a hydrogen-charged material to explore primary features of the streamline integration methodology while providing new results relevant to hydrogen embrittlement at engineering scales. Ductile crack propagation occurs through a homogeneous, high solubility material characteristic of niobium and through a steel weld in the presence of hydrogen. The constitutive model includes the influence of hydrogen on elastic-plastic regimes of material response at the continuum level, emph{e.g.} hydrogen-induced material softening, based on the hydrogen-enhanced, localized plasticity (HELP) mechanism, and reflects the amount of hydrogen in the material under stress and the intensity of hydrogen-induced softening in the material. Achievements using this two-dimensional framework encouraged further extensions of the research to a fully three-dimensional setting. Subsequent work, and the focal point of this thesis, develops a finite element formulation to investigate key features of the elastic-plastic fields near a steadily advancing crack under three-dimensional, small-scale yielding conditions. The computational model represents a structurally thin component constructed of a material (e.g. Al and Ti alloys) with flow stress and fracture toughness properties that together limit the size of the in-plane plastic zone during steady growth to no more than several multiples of the plate thickness. These studies consider a straight crack front advancing under local and global mode-I loading in a moderately hardening material. The nonsingular T-stress provides a first-order estimate of geometry and loading mode (e.g. tension vs. bending) effects on elastic-plastic, crack front fields. The T-stress has a marked effect on measured crack-growth resistance curves (J-da) -- trends most computational models confirm using a two-dimensional setting. In the first computations of this type to be modeled, the 3D numerical results here demonstrate similarity scaling of the crack front response -- stresses, strains, and displacements -- in terms of two non-dimensional loading parameters. These fields serve as input to key engineering failure models for brittle and ductile crack growth and provide estimates of the apparent fracture toughness linked to changes of the material flow response, geometry, and applied loading. For the first time in the scientific literature, these studies document 3D analyses of steady-state crack growth and represent a key advance in computational analyses of crack extension.

Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 1308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strength and Toughness of Materials written by Toshiro Kobayashi and published by Springer Science & Business Media. This book was released on 2004-03-04 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the shift from the Metal Age progresses, materials engineers and materials scientists seek new analytical and design methods to create stronger and more reliable materials. Based on extensive research and developmental work done at the author’s multi-disciplinary material laboratory, this graduate-level and professional reference addresses the relationship between fracture mechanisms (macroscale) and the microscopic, with the goal of explaining macroscopic fracture behavior based on a microscopic fracture mechanism. A careful fusion of mechanics and materials science, this text and monograph systematically considers an array of materials, from metals through ceramics and polymers, and demonstrates lab-tested strategies to develop desirable high-temperature materials for technological applications.