Download or read book Mechanics of Fracture Initiation and Propagation written by George C. Sih and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: The assessment of crack initiation and/or propagation has been the subject of many past discussions on fracture mechanics. Depending on how the chosen failure criterion is combined with the solution of a particular theory of continuum mechanics, the outcome could vary over a wide range. Mod elling of the material damage process could be elusive if the scale level of observation is left undefined. The specification of physical dimension alone is not sufficient because time and temperature also play an intimate role. It is only when the latter two variables are fixed that failure predictions can be simplified. The sudden fracture of material with a pre-existing crack is a case in point. Barring changes in the local temperature,* the energy released to create a unit surface area of an existing crack can be obtained by considering the change in elastic energy of the system before and after crack extension. Such a quantity has been referred to as the critical energy release rate, G e, or stress intensity factor, K Ie. Other parameters, such as the crack opening displacement (COD), path-independent J-integral, etc. , have been proposed; their relation to the fracture process is also based on the energy release concept. These one-parameter approaches, however, are unable simultaneously to account for the failure process of crack initiation, propagation and onset of rapid fracture. A review on the use of G, K I, COD, J, etc. , has been made by Sih [1,2].

Download or read book Problems of mixed mode crack propagation written by E.E. Gdoutos and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is not just another book on fracture mechanics. In recent years, there have been many books published on this subject in an attempt to assess the state of the art and its applications. The majority of the work dealt with energy release rate or critical stress intensity factor and is applicable only to fracture toughness testing. The main reason for this restriction is that the energy release concept cannot easily be extended to mixed mode fracture that occurs in practice as the rule rather than the exception. Cracks will normally curve or turn because the direction of loading can change as a function of time. Their directions of growth cannot be assumed as an a priori and must be determined from a pre-assumed criterion. Analysts are still perplexed with selecting an appropriate fracture criterion because it requires much discernment and judgement. Criteria which often appeared valid for idealized situations are quickly dis credited when encountering more complex physical phenomena. Moreover, the claim of generality cannot be justified on the basis of agreement between theory and experiment for a few simple examples.

Download or read book Stochastic Crack Propagation written by Giora Maymon and published by Academic Press. This book was released on 2018-01-10 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stochastic Crack Propagation: Essential Practical Aspects describes a feature important to the analysis of stochastic crack propagation, starting with essential background theory. Processes, or phenomena, which are of practical importance in the work of design engineers or R&D teams are described chapter by chapter. Many examples are described and supported by listed references, and files of data that can be used with specialist software to practice design situations are included. Advice on how to use various computer programs to design and predict for stochastic crack growth is also provided, giving professionals a complete guide. Presents instructions and exercises in the ideal format for professionals, focusing on applications Explains a methodology on how to optimize the engineering design process by including stochastic crack growth behavior Provides computational files to help readers get up-to-speed with design using programs like ANSYS and NASTRAN for stochastic crack growth

Download or read book Fatigue Crack Propagation in Metals and Alloys written by Ulrich Krupp and published by John Wiley & Sons. This book was released on 2007-04-09 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive overview of the whole field of fatigue and fracture of metallic materials covers both the theoretical background and some of the latest experimental techniques. It provides a summary of the complex interactions between material microstructure and cracks, classifying them with respect to the overall damage process with a focus on microstructurally short cracks and dynamic embrittlement. It furthermore introduces new concepts for the numerical treatment of fatigue microcrack propagation and their implementation in fatigue-life prediction models.This comprehensive overview of the whole field of fatigue and fracture of metallic materials covers both the theoretical background and the latest experimental techniques. It provides a summary of the complex interactions between material microstructure and cracks, classifying them with respect to the overall damage process. It furthermore introduces new concepts for the numerical treatment of fatigue microcrack propagation and their implementation in fatigue-life prediction models.

Download or read book A Practical Approach to Fracture Mechanics written by Jorge Luis González-Velázquez and published by Elsevier. This book was released on 2020-10-08 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Practical Approach to Fracture Mechanics provides a concise overview on the fundamental concepts of fracture mechanics, discussing linear elastic fracture mechanics, fracture toughness, ductile fracture, slow crack propagation, structural integrity, and more. The book outlines analytical and experimental methods for determining the fracture resistance of mechanical and structural components, also demonstrating the use of fracture mechanics in failure analysis, reinforcement of cracked structures, and remaining life estimation. The characteristics of crack propagation induced by fatigue, stress-corrosion, creep, and absorbed hydrogen are also discussed. The book concludes with a chapter on the structural integrity analysis of cracked components alongside a real integrity assessment. This book will be especially useful for students in mechanical, civil, industrial, metallurgical, aeronautical and chemical engineering, and for professional engineers looking for a refresher on core principles. Concisely outlines the underlying fundamentals of fracture mechanics, making physical concepts clear and simple and providing easily-understood applied examples Includes solved problems of the most common calculations, along with step-by-step procedures to perform widely-used methods in fracture mechanics Demonstrates how to determine stress intensity factors and fracture toughness, estimate crack growth rate, calculate failure load, and other methods and techniques

Download or read book Extended Finite Element Method for Crack Propagation written by Sylvie Pommier and published by John Wiley & Sons. This book was released on 2013-03-04 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: Novel techniques for modeling 3D cracks and their evolution in solids are presented. Cracks are modeled in terms of signed distance functions (level sets). Stress, strain and displacement field are determined using the extended finite elements method (X-FEM). Non-linear constitutive behavior for the crack tip region are developed within this framework to account for non-linear effect in crack propagation. Applications for static or dynamics case are provided.

Download or read book Fracture Mechanics and Crack Growth written by Naman Recho and published by John Wiley & Sons. This book was released on 2012-12-27 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents recent advances related to the following two topics: how mechanical fields close to material or geometrical singularities such as cracks can be determined; how failure criteria can be established according to the singularity degrees related to these discontinuities. Concerning the determination of mechanical fields close to a crack tip, the first part of the book presents most of the traditional methods in order to classify them into two major categories. The first is based on the stress field, such as the Airy function, and the second resolves the problem from functions related to displacement fields. Following this, a new method based on the Hamiltonian system is presented in great detail. Local and energetic approaches to fracture are used in order to determine the fracture parameters such as stress intensity factor and energy release rate. The second part of the book describes methodologies to establish the critical fracture loads and the crack growth criteria. Singular fields for homogeneous and non-homogeneous problems near crack tips, v-notches, interfaces, etc. associated with the crack initiation and propagation laws in elastic and elastic-plastic media, allow us to determine the basis of failure criteria. Each phenomenon studied is dealt with according to its conceptual and theoretical modeling, to its use in the criteria of fracture resistance; and finally to its implementation in terms of feasibility and numerical application. Contents 1. Introduction. Part 1: Stress Field Analysis Close to the Crack Tip 2. Review of Continuum Mechanics and the Behavior Laws. 3. Overview of Fracture Mechanics. 4. Fracture Mechanics. 5. Introduction to the Finite Element Analysis of Cracked Structures. Part 2: Crack Growth Criteria 6. Crack Propagation. 7. Crack Growth Prediction in Elements of Steel Structures Submitted to Fatigue. 8. Potential Use of Crack Propagation Laws in Fatigue Life Design.

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 Fatigue Damage Crack Growth and Life Prediction written by F. Ellyin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue failure is a multi-stage process. It begins with the initiation of cracks, and with continued cyclic loading the cracks propagate, finally leading to the rupture of a component or specimen. The demarcation between the above stages is not well-defined. Depending upon the scale of interest, the variation may span three orders of magnitude. For example, to a material scientist an initiated crack may be of the order of a micron, whereas for an engineer it can be of the order of a millimetre. It is not surprising therefore to see that investigation of the fatigue process has followed different paths depending upon the scale of phenomenon under investigation. Interest in the study of fatigue failure increased with the advent of industrial ization. Because of the urgent need to design against fatigue failure, early investiga tors focused on prototype testing and proposed failure criteria similar to design formulae. Thus, a methodology developed whereby the fatigue theories were proposed based on experimental observations, albeit at times with limited scope. This type of phenomenological approach progressed rapidly during the past four decades as closed-loop testing machines became available.

Download or read book Handbook of Fatigue Crack Propagation in Metallic Structures written by A. Carpinteri and published by Newnes. This book was released on 2012-12-02 with total page 834 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this Handbook is to provide a review of the knowledge and experiences in the field of fatigue fracture mechanics. It is well-known that engineering structures can fail due to cyclic loading. For instance, a cyclically time-varying loading reduces the structure strength and can provoke a fatigue failure consisting of three stages: (a) crack initiation (b) crack propagation and (c) catastrophic failure. Since last century many scientists have tried to understand the reasons for the above-mentioned failures and how to prevent them. This Handbook contains valuable contributions from leading experts within the international scientific community and covers many of the important problems associated with the fatigue phenomena in civil, mechanical and nuclear engineering.

Download or read book Fatigue Crack Growth in Rubber Materials written by Gert Heinrich and published by Springer Nature. This book was released on 2021-03-23 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book summarizes recent international research and experimental developments regarding fatigue crack growth investigations of rubber materials. It shows the progress in fundamental as well as advanced research of fracture investigation of rubber material under fatigue loading conditions, especially from the experimental point of view. However, some chapters will describe the progress in numerical modeling and physical description of fracture mechanics and cavitation phenomena in rubbers. Initiation and propagation of cracks in rubber materials are dominant phenomena which determine the lifetime of these soft rubber materials and, as a consequence, the lifetime of the corresponding final rubber parts in various fields of application. Recently, these phenomena became of great scientific interest due to the development of new experimental methods, concepts and models. Furthermore, crack phenomena have an extraordinary impact on rubber wear and abrasion of automotive tires; and understanding of crack initiation and growth in rubbers will help to support the growthing number of activities and worldwide efforts of reduction of tire wear losses and abrasion based emissions.

Download or read book Gear Crack Propagation Path Studies Guidelines for Ultra Safe Design written by and published by . This book was released on 2001 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design guidelines have been established to prevent catastrophic rim fracture failure modes when considering gear tooth bending fatigue. Analysis was performed using the finite element method with principles of linear elastic fracture mechanics. Crack propagation paths were predicted for a variety of gear tooth and rim configurations. The effects of rim and web thicknesses, initial crack locations, and gear tooth geometry factors such as diametral pitch, number of teeth, pitch radius, and tooth pressure angle were considered. Design maps of tooth/rim fracture modes including effects of gear geometry, applied load, crack size, and material properties were developed. The occurrence of rim fractures significantly increased as the backup ratio (rim thickness divided by tooth height) decreased. The occurrence of rim fractures also increased as the initial crack location was moved down the root of the tooth. Increased rim and web compliance increased the occurrence of rim fractures. For gears with constant pitch radii, coarser-pitch teeth increased the occurrence of tooth fractures over rim fractures. Also, 250 pressure angle teeth had an increased occurrence of tooth fractures over rim fractures when compared to 200 pressure angle teeth. For gears with constant number of teeth or gears with constant diametral pitch, varying size had little or no effect on crack propagation paths.

Download or read book Proceedings of an international conference on Dynamic Crack Propagation written by George C. Sih and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 707 pages. Available in PDF, EPUB and Kindle. Book excerpt: The planning meeting for a conference on Dynamic Crack Propagation was held at M.LT. in February 1971 and attended by research workers from several industrial, governmental and academic organizations. It was felt that a more specialized meeting would provide a better opportunity for both U.S. and foreign researchers to exchange their ideas and views on dynamic fracture, a subject which is seldom emphasized in national or international fracture conferences. Dynamic crack propagation has been a concern to specialists in many fields: continuum mechanics, metallurgy, geology, polymer chemistry, orthopedics, applied mathematics, as well as structural design and testing. It impinges on a wide variety of problems such as rock breaking and earthquakes, pressure vessels and line pipes, comminution and the per formance of armament and ordnance, etc. Advances have been numerous, covering theories and experiments from both the microscopic and macro scopic points of view. Hence, the need for comparing the theoretical and experimental results and bridging the gaps between the atomistic and continuum approaches must be constantly emphasized. It also appeared that the overall problem of dynamic fracture could benefit from a con solidation of crack models proposed for the various types of materials: metals, ceramics, composites, rocks, glasses, polymers and biomaterials.

Download or read book Accelerated Crack Propagation of Titanium by Methanol Halogenated Hydrocarbons and Other Solutions written by and published by . This book was released on 1967 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Consideration of Moving Tooth Load in Gear Crack Propagation Predictions written by and published by . This book was released on 2000 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Robust gear designs consider not only crack initiation, but crack propagation trajectories for a fail-safe design. In actual gear operation, the magnitude as well as the position of the force changes as the gear rotates through the mesh. A study to determine the effect of moving gear tooth load on crack propagation predictions was performed. Two dimensional analysis of an involuted spur gear and three-dimensional analysis of a spiral-bevel pinion gear using the finite element method and boundary element method were studied and compared to experiments. A modified theory for predicting gear crack propagation paths based on the criteria of Erdogan and Sih was investigated. Crack simulation based on calculated stress intensity factors and mixed mode crack angle prediction techniques using a simple static analysis in which the tooth load was located at the highest point of single tooth contact was validated. For three-dimensional analysis, however, the analysis was valid only as long as the crack did not approach the contact region on the tooth.

Download or read book Stochastic Crack Propagation with Applications to Durability and Damage Tolerance Analyses written by J. N. Yang and published by . This book was released on 1985 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various stochastic models for fatigue crack propagation under either constant amplitude or spectrum loadings have been investigated. These models are based on the assumption that the crack growth rate is a lognormal random process, including the general lognormal random process, lognormal white noise process, lognormal random variable, and second moment approximations, such as Weibull, gamma, lognormal and Gaussian closure approximations. Extensive experimental data have been used for the correlation study with various stochastic models. These include fastener hole specimens under fighter or bomber spectrum laodings and center-cracked specimens under constant amplitude loads. The data sets for the fastener hole specimens cover adequately different loading conditions, environments, load transfers and crack size range. It is shown that the white noise process is definitely not a valid model for fatigue crack propagation.

Download or read book Effects of Changing Stress Amplitude on the Rate of Fatigue crack Propagation in Two Aluminum Alloys written by C. M. Hudson and published by . This book was released on 1961 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of fatigue tests with specimens subjected to constant amplitude and two-step axial loads were conducted on 12-inch-wide sheet specimens of 2024-T3 and 7075-T6 aluminum alloy to study the effects of a change in stress level on fatigue-crack propagation. Comparison of the results of the tests in which the specimens were tested at first a high and then a low stress level with those of the constant-stress-amplitude tests indicated that crack propagation was generally delayed after the transition to the lower stress level. In the tests in which the specimens were tested at first a low and then a high stress level, crack propagation continued at the expected rate after the change in stress levels.