Download or read book An Investigation of the Shape and Extent of Crack Tip Plastic Zones in Fatigue Crack Propagation and the Role of the Overload Plastic Zone Retardation written by James Milligan Larsen and published by . This book was released on 1977 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Crack Tip Plasticity written by TS. Cook and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical calculation and experimental measurement of fatigue crack tip plastic zone size are reviewed, and recent plastic zone measurements using selected area electron channeling are presented. The relationships between state of stress, measurement technique, and plastic zone shape and size are discussed. It is shown that there exists only limited agreement between theory and experimental measurements, but that general conclusions concerning the appropriate plastic zone dimensions for various conditions can be drawn. The importance of plastic zone shape is demonstrated for the case of overload-induced crack growth retardation.

Download or read book Cyclic Stress Strain and Plastic Deformation Aspects of Fatigue Crack Growth written by L. F. Impellizzeri and published by ASTM International. This book was released on 1977 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cyclic Stress Strain and plastic deformation Aspects of fatigue crack growth written by L. F. Impellizzeri and published by ASTM International. This book was released on 1977 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanics and Mechanisms of Fracture written by Alan F. Liu and published by ASM International. This book was released on 2005-01-01 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Techniques in Metal Deformation Testing written by Robert H. Wagoner and published by . This book was released on 1983 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanisms of Overload Retardation During Fatigue Crack Propagation written by PJ. Bernard and published by . This book was released on 1976 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of single overloads on room-temperature fatigue crack growth has been studied in two steels of markedly different yield stresses. The observed retardation effects have been presented and the evidence suggests that overload retardation is primarily due to residual compressive stresses generated in the crack tip region, and associated with crack closure effects. The results have been rationalized in terms of a fatigue crack growing through overload plastic zones of different shapes and sizes associated with plane stress and plane strain deformation.

Download or read book Paper written by and published by . This book was released on 1975 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement and Analysis of Critical Crack Tip Processes Associated with Variable Amplitude Fatigue Crack Growth written by and published by . This book was released on 1983 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Elastic plastic Material Response on Fatigue Crack Surface Profiles Due to Overload Interactions written by Recai Heper and published by . This book was released on 2002 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Elastic-plastic material response to applied single overloads on crack surface profiles was investigated using finite element fatigue crack closure simulations at constant stress intensity factor situation. The modeling procedure and the simulation results (the effect of overload ratio, near and far interaction of two single overloads, increasing R ratio while keeping DKOL/DK ratio fixed, increasing R ratio while keeping KOL/Kmax ratio fixed, distance between periodic overloads, mesh size and appropriate crack closure definition) were discussed based on experimental and numerical studies reported in literature on overload interactions. Differential surface profiles (difference of crack surface profiles of constant amplitude and of variable (overload) amplitude) were found useful in identifying and understanding the effect of load interactions. Differential surface profile of a single overload (differential hump profile) was expressed with a transient function when load ratio was equal to zero. When load ratio was higher than zero additional plastic deformation occurred. Amount of this added deformation was approximately equal to additional crack opening displacements due to Kmin for the fictitious crack, the tip of which lied ahead of the overload point by (differential) overload plastic zone size. Decreasing the distance between (equally distanced) periodic overloads led to an increase in base plastic deformations attached at the flanks of the crack and to smaller but more frequent humps. As the distance between periodic overloads continued to decrease, base plastic deformation level reached that of block overload. The spring effect of hump which inhibited reversed plastic deformations during closure was reflected by the differential hump profile being nonzero outside of the overload plastic zone and also by the second overload leading to a larger differential hump profile even if the second overload was applied outside of the overload plastic zone size of the first overload.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1976 with total page 990 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Mechanisms written by J. T. Fong and published by ASTM International. This book was released on 1979 with total page 913 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of the Crack Tip Deformation Characteristics of Slowly Growing Fatigue Cracks written by James Lankford (Jr) and published by . This book was released on 1974 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The technique of selected area electron channeling has been quantified and used to map the shape and quantitative strain distribution within the plastic zones attending fatigue crack tips in 304 stainless steel, 6061-T6 aluminum, and Fe-3Si steel. Simultaneously, crack tip operning displacement, the mechanisms of yielding and decohesion, and maximum shear strains have been measured using high magnification SEM of replicas. Overload plastic zones and their relation to fatigue crack retardation have been characterized. Observed values of all of these parameters have been compared with predictions of various analytical models.

Download or read book Basic Questions in Fatigue written by Jeffrey T. Fong and published by ASTM International. This book was released on 1988 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Displacement Based Method for Predicting Plasticity Induced Fatigue Crack Closure written by ME. Pawlik and published by . This book was released on 1999 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical method for predicting closure and its effects on thermomechanical crack growth has been developed. A finite element model, using linear-elastic fracture mechanics shape functions, is employed to predict crack tip displacements. The effective changes in stress intensity, and therefore crack growth, are obtained from the minimum and maximum crack tip displacement predictions. When a flaw is loaded in Mode I, a ligament of material ahead of the flaw yields, and a maximum crack tip displacement is computed. Upon unloading, plastically deformed material from prior plastic zones acts to limit the minimum displacements of the crack tip. The material is modeled as elastic-perfectly plastic. The yield strength of the material is varied based on the degree of constraint. The upper limit of constraint is a plane strain condition while the lowest constraint is a plane stress condition. The level of constraint is predicted by relating the stress intensity to the thickness of the component. Temperatures also affect yield strength, along with stiffness, and can cause the plastic zone to expand due to creep. During variable-amplitude loadings, and/or temperature changes, the irregular shape of the wake can be accommodated with this numerical procedure. The method has proven to accurately account for load interaction effects such as delayed retardation, crack arrest, initial accelerations following overloads, and the transient growth and stabilization of closure level with number of overloads. This method has been verified against data obtained in the literature, and data collected under the program in which the method was developed, NASA's High Speed Research [1].

Download or read book Fatigue and Durability of Structural Materials written by Gary R. Halford and published by ASM International. This book was released on 2006 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue and Durability of Structural Materials explains how mechanical material behavior relates to the design of structural machine components. The major emphasis is on fatigue and failure behavior using engineering models that have been developed to predict, in advance of service, acceptable fatigue and other durability-related lifetimes. The book covers broad classes of materials used for high-performance structural applications such as aerospace components, automobiles, and power generation systems. Coverage focuses on metallic materials but also addresses unique capabilities of important nonmetals. The concepts are applied to behavior at room or ambient temperatures; a planned second volume will address behavior at higher-temperatures. The volume is a repository of the most significant contributions by the authors to the art and science of material and structural durability over the past half century. During their careers, including 40 years of direct collaboration, they have developed a host of durability models that are based on sound physical and engineering principles. Yet, the models and interpretation of behavior have a unique simplicity that is appreciated by the practicing engineer as well as the beginning student. In addition to their own pioneering work, the authors also present the work of numerous others who have provided useful results that have moved progress in these fields. This book will be of immense value to practicing mechanical and materials engineers and designers charged with producing structural components with adequate durability. The coverage is appropriate for a range of technical levels from undergraduate engineering students through material behavior researchers and model developers. It will be of interest to personnel in the automotive and off-highway vehicle manufacturing industry, the aeronautical industry, space propulsion and the power generation/conversion industry, the electric power industry, the machine tool industry, and any industry associated with the design and manufacturing of mechanical equipment subject to cyclic loads.