Download or read book Fracture Process Zone Studies of High Temperature Structural Ceramics written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our work on this AFOSR-funded project successfully completed the PFT database through 1280#161#C for alumina and through 600#161#C for the magnesium aluminate spinel, elucidating the importance of crystal structure and fracture topography on the toughening characteristics. We now have a firm understanding of the relationship between the PFT method and the crack growth resistance curve, and are now developing further insights into the role of the microstructural constituents in the crack growth resistance behavior. A first-generation finite element model of the fracture specimen uses both the moire and PFT data to faithfully predict the bulk behavior. Our examination of the electronic speckle pattern interferometry (ESPI) system for elevated temperature measurements of the crack profile have been discontinued, due to inadequate resolution of the available control software. Therefore, the moire experiments are now being modified for elevated temperature studies. We are initiating a second-generation model of the pullout micromechanism to predict the stress-displacement relationship based on the crystal structure properties, grain size distribution, and elastic properties. In response to the detailed studies by the PFT technique, modified micromechanisms are now being incorporated into the model, including high compliance bridging ligaments, such as asperity loading, grain rotation and ligament bending.
Download or read book Fracture Mechanics of Ceramics written by R.C. Bradt and published by Springer. This book was released on 1996-10-31 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volumes 11 and 12 of the series contain the 90 papers of an international symposium in Karlsruhe, Germany, in July 1995, which continued the investigation of failure behavior in monolithic engineering ceramics and reinforced ceramics. Addresses recent developments in the understanding and modelling
Download or read book Elevated Temperature Process Zone Modeling of Small Cracks in Structural Ceramics Under Static and Cyclic Loading written by and published by . This book was released on 2000 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project focused on the study of the effects of microstructural features on the fracture process of high temperature structural ceramic materials that operate under cyclic loading environments. The ability to model these effects and the prediction of the deformation behavior also become an important consideration, as it provides a direct link to the design cycle for both, processing and design engineers. The project evaluated cyclic effects, high cycle fatigue behavior, and elevated temperature effects under these conditions. Evaluation of the effects of cyclic loading are performed using pre-cracked tensile test specimens (PFT) and bulk specimens by Moire Interferometry. Development of finite element and simple micromechanical models for predictions of the observed behavior also presented. It is observed that hysteretic load-displacement loops arise as the primary characteristic of the behavior, although gross-slip behavior is seen under certain circumstances.
Download or read book Fracture Process Zone Modeling of Small Cracks in Structural Ceramics Under Static and Cyclic Loading written by and published by . This book was released on 2000 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project focused on the study of the effects of microstructural features on the fracture process of high temperature structural ceramic materials that operate under cyclic loading environments. The ability to model these effects and the prediction of the deformation behavior also become an important consideration, as it provides a direct link to the design cycle for both, processing and design engineers. The project evaluated cyclic effects, high cycle fatigue behavior, and elevated temperature effects under these conditions. Evaluation of the effects of cyclic loading are performed using pre-cracked tensile test specimens (PFT) and bulk specimens by Moire Interferometry. Development of finite element and simple micromechanical models for predictions of the observed behavior also presented. It is observed that hysteretic load-displacement loops arise as the primary characteristic of the behavior, although gross-slip behavior is seen under certain circumstances.
Download or read book Process Zone Modeling of Elevated Temperature Structural Ceramics written by and published by . This book was released on 1997 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Post fracture tensile (PFT) experiments on two microstructures elucidated the crystallographic and microstructural contributions to the pullout resistance. In alumina, the average residual stresses arising from TEA diminish with increasing temperature, causing two effects evidenced by a general downward shift of the characteristic wake stress-displacement curves. Similar tests conducted on the cubic spinel exhibited no change in bridging efficiency. Similar experiments at the higher temperatures identify topographic changes of the fracture surface as the critical influence on the observed increased toughening behavior. Also, using the post fracture tensile (PFT) technique, the isolated wake region was tested in direct tension to determine the wake stiffness, offering further insight to those featured of the microstructure that control the bridging efficiency. From these studies, we found that alternate, more compliant micro-mechanisms must be included in the modeling effort to faithfully represent the relatively low measured wake stiffnesses.
Download or read book Fracture Mechanics of Ceramics written by R. C. Bradt and published by Springer. This book was released on 2012-10-12 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: These volumes, 7 and 8, of Fracture Mechanics of Ceramics constitute the proceedings of an international symposium on the fracture mechanics of ceramic materials held at Virginia Polytechnic Institute and State University, Blacksburg, Virginia on June 19, 20 and 21, 1985. These proceedings constitute the fourth pair of volumes of a continuing series of conferences. The theme of this conference, as the previous three, focused on the mechanical behavior of ceramic materials in terms of the characteristics of cracks, particularly the roles which they assume in the fracture process. The 78 contributed papers by over 100 authors and co-authors represent the current state of the field. They address many of the theoretical and practical problems of interest to those concerned with brittle fracture. The program chairmen gratefully acknowledge the financial assistance for the Symposium provided by the EXXON Foundation, the Army Research Office, the Natio~al Science Foundation, and the Office of Naval Research. Without their support, this conference simply would not have been possible. The suggestions of Drs. J. C. Hurt, R. C. Pohanka, and L. Toth were particularly helpful in assuring the success of this symposium. Special appreciation is extended to Professor J. I. Robertson, C. P. Miles Professor of History. whose presentation following the banquet on the American Civil War was very well received by the audience. Finally, we wish to also thank our joint secretaries, especially Karen Snider, for their patience and help in finally bringing these proceedings to press.
Download or read book Designing with Structural Ceramics written by R.W. Davidge and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last 30 years have seen a steady development in the range of ceramic materials with potential for high temperature engineering applications: in the 60s, self-bonded silicon carbide and reaction-bonded silicon nitride; in the 70s, improved aluminas, sintered silicon carbide and silicon nitrides (including sialons); in the 80s, various toughened Zr0 materials, ceramic matrix composites reinforced with silicon 2 carbide continuous fibres or whiskers. Design methodologies were evolved in the 70s, incorporating the principles of fracture mechanics and the statistical variation and time dependence of strength. These have been used successfully to predict the engineering behaviour of ceramics in the lower range of temperature. In spite of the above, and the underlying thermodynamic arguments for operations at higher temperatures, there has been a disappointing uptake of these materials in industry for high temperature usc. Most of the successful applications are for low to moderate temperatures such as seals and bearings, and metal cutting and shaping. The reasons have been very well documented and include: • Poor predictability and reliability at high temperature. • High costs relative to competing materials. • Variable reproducibility of manufacturing processes. • Lack of sufficiently sensitive non-destructive techniques. With this as background, a Europhysics Industrial Workshop sponsored by the European Physical Society (EPS) was organised by the Netherlands Energy Research Foundation (ECN) and the Institute for Advanced Materials of the Joint Research Centre (JRC) of the EC, at Petten, North Holland, in April 1990 to consider the status of thermomechanical applications of engineering ceramics.
Download or read book Mechanical Properties of Ceramics written by Joshua Pelleg and published by Springer Science & Business. This book was released on 2014-04-22 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the mechanical properties of ceramics and aims to provide both a solid background for undergraduate students, as well as serving as a text to bring practicing engineers up to date with the latest developments in this topic so they can use and apply these to their actual engineering work. Generally, ceramics are made by moistening a mixture of clays, casting it into desired shapes and then firing it to a high temperature, a process known as 'vitrification'. The relatively late development of metallurgy was contingent on the availability of ceramics and the know-how to mold them into the appropriate forms. Because of the characteristics of ceramics, they offer great advantages over metals in specific applications in which hardness, wear resistance and chemical stability at high temperatures are essential. Clearly, modern ceramics manufacturing has come a long way from the early clay-processing fabrication method, and the last two decades have seen the development of sophisticated techniques to produce a large variety of ceramic material. The chapters of this volume are ordered to help students with their laboratory experiments and guide their observations in parallel with lectures based on the current text. Thus, the first chapter is devoted to mechanical testing. A chapter of ductile and superplastic ceramic is added to emphasize their role in modern ceramics (chapter 2). These are followed by the theoretical basis of the subject. Various aspects of the mechanical properties are discussed in the following chapters, among them, strengthening mechanisms, time dependent and cyclic deformation of ceramics. Many practical illustrations are provided representing various observations encountered in actual ceramic-structures of particularly technical significance. A comprehensive list of references at the end of each chapter is included in this textbook to provide a broad basis for further studying the subject. The work also contains a unique chapter on a topic not discussed in other textbooks on ceramics concerning nanosized ceramics. This work will also be useful as a reference for materials scientists, not only to those who specialize in ceramics.
Download or read book Structural Ceramics Fracture Mechanics written by Yoshiteru Hamano and published by . This book was released on 1989 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High temperature Cyclic Fatigue and Fracture Properties in Silicon Nitride Structural Ceramics written by Alexander Ziegler and published by . This book was released on 1999 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fracture Mechanics of Ceramics written by R.C. Bradt and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: These volumes, 9 and 10, of Fracture Mechanics of Ceramics constitute the proceedings of an international symposium on the fracture mechanics of ceramic materials held at the Japan Fine Ceramics Center, Nagoya, Japan on July 15, 16, 17, 1991. These proceedings constitute the fifth pair of volumes of a continuing series of conferences. Volumes 1 and 2 were from the 1973 symposium, volumes 3 and 4 from a 1977 symposium, and volumes 5 and 6 from a 1981 symposium all of which were held at The Pennsylvania State University. Volumes 7 and 8 are from the 1985 symposium which was held at the Virginia Polytechnic Institute and State University. The theme ofthis conference, as for the previous four, focused on the mechanical behavior ofceramic materials in terms of the characteristics of cracks, particularly the roles which they assume in the fracture processes and mechanisms. The 82 contributed papers by over 150 authors and co-authors represent the current state of that field. They address many of the theoretical and practical problems ofinterest to those scientists and engineers concerned with brittle fracture.
Download or read book Fracture Mechanics of Ceramics written by R.C. Bradt and published by Springer Science & Business Media. This book was released on 2013-03-07 with total page 645 pages. Available in PDF, EPUB and Kindle. Book excerpt: These volumes, 9 and 10, of Fracture Mechanics of Ceramics constitute the proceedings of an international symposium on the fracture mechanics of ceramic materials held at the Japan Fine Ceramics Center, Nagoya, Japan on July 15, 16, 17, 1991. These proceedings constitute the fifth pair of volumes of a continuing series of conferences. Volumes 1 and 2 were from the 1973 symposium, volumes 3 and 4 from a 1977 symposium, and volumes 5 and 6 from a 1981 symposium all of which were held at The Pennsylvania State University. Volumes 7 and 8 are from the 1985 symposium which was held at the Virginia Polytechnic Institute and State University. The theme ofthis conference, as for the previous four, focused on the mechanical behavior ofceramic materials in terms of the characteristics ofcracks, particularly the roles which they assume in the fracture processes and mechanisms. The 82 contributed papers by over 150 authors and co-authors represent the current state of that field. They address many of the theoretical and practical problems ofinterest to those scientists and engineers concerned with brittle fracture.
Download or read book Advanced Structural Ceramics written by Bikramjit Basu and published by John Wiley & Sons. This book was released on 2011-09-26 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the area of advanced ceramic composites broadly, providing important introductory chapters to fundamentals, processing, and applications of advanced ceramic composites. Within each section, specific topics covered highlight the state of the art research within one of the above sections. The organization of the book is designed to provide easy understanding by students as well as professionals interested in advanced ceramic composites. The various sections discuss fundamentals of nature and characteristics of ceramics, processing of ceramics, processing and properties of toughened ceramics, high temperature ceramics, nanoceramics and nanoceramic composites, and bioceramics and biocomposites.
Download or read book The Variational Approach to Fracture written by Blaise Bourdin and published by Springer Science & Business Media. This book was released on 2008-04-19 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting original results from both theoretical and numerical viewpoints, this text offers a detailed discussion of the variational approach to brittle fracture. This approach views crack growth as the result of a competition between bulk and surface energy, treating crack evolution from its initiation all the way to the failure of a sample. The authors model crack initiation, crack path, and crack extension for arbitrary geometries and loads.
Download or read book Fracture Mechanics of Ceramics written by R. C. Bradt and published by Springer. This book was released on 1986 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: These volumes, 7 and 8, of Fracture Mechanics of Ceramics constitute the proceedings of an international symposium on the fracture mechanics of ceramic materials held at Virginia Polytechnic Institute and State University, Blacksburg, Virginia on June 19, 20 and 21, 1985. These proceedings constitute the fourth pair of volumes of a continuing series of conferences. The theme of this conference, as the previous three, focused on the mechanical behavior of ceramic materials in terms of the characteristics of cracks, particularly the roles which they assume in the fracture process. The 78 contributed papers by over 100 authors and co-authors represent the current state of the field. They address many of the theoretical and practical problems of interest to those concerned with brittle fracture. The program chairmen gratefully acknowledge the financial assistance for the Symposium provided by the EXXON Foundation, the Army Research Office, the Natio~al Science Foundation, and the Office of Naval Research. Without their support, this conference simply would not have been possible. The suggestions of Drs. J. C. Hurt, R. C. Pohanka, and L. Toth were particularly helpful in assuring the success of this symposium. Special appreciation is extended to Professor J. I. Robertson, C. P. Miles Professor of History. whose presentation following the banquet on the American Civil War was very well received by the audience. Finally, we wish to also thank our joint secretaries, especially Karen Snider, for their patience and help in finally bringing these proceedings to press.
Download or read book Fracture Mechanics of Ceramics written by R.C. Bradt and published by Springer. This book was released on 2005-07-29 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 8th International Symposium on fracture mechanics of ceramics was held in on the campus of the University of Houston, Houston, TX, USA, on February 25-28, 2003. With the natural maturing of the fields of structural ceramics, this symposium focused on nano-scale materials, composites, thin films and coatings as well as glass. The symposium also addressed new issues on fundamentals of fracture mechanics and contact mechanics, and a session on reliability and standardization.
Download or read book Structural Ceramics and Testing of Brittle Materials written by Samuel J. Acquaviva and published by . This book was released on 1968 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
