[PDF] Fatigue Crack Growth Behavior Of Surface Cracks In Silicon Nitride eBook

Author : A. Kanagawa
Publisher :
Page : 13 pages
File Size : 26,73 MB
Release : 1994
Category : Bridging
ISBN :

GET BOOK

Cyclic fatigue crack growth tests of silicon nitride specimens with surface cracks as well as through-the-thickness cracks were carried out. The surface crack length was measured by a surface film gage technique. The fatigue crack growth rate for surface cracks was less than that for through-the-thickness cracks. From SEM observations, more significant bridging was found in the wake of surface cracks compared to through-the-thickness cracks. From evaluations of the stress shielding effect due to bridging based on the measurements of the crack mouth opening displacement, it was found that the crack growth curve determined from the crack tip stress intensity factor Ktip for surface cracks almost coincided with that for through-the-thickness cracks.

Author : K.S. Ravichandran
Publisher : Elsevier
Page : 511 pages
File Size : 27,12 MB
Release : 1999-09-30
Category : Technology & Engineering
ISBN : 0080569706

GET BOOK

This book contains the fully peer-reviewed papers presented at the Third Engineering Foundation Conference on Small Fatigue Cracks, held under the chairmanship of K.S. Ravichandran and Y. Murakami during December 6-11, 1998, at the Turtle Bay Hilton, Oahu, Hawaii. This book presents a state-of-the-art description of the mechanics, mechanisms and applications of small fatigue cracks by most of the world's leading experts in this field. Topics ranging from the mechanisms of crack initiation, small crack behavior in metallic, intermetallic, ceramic and composite materials, experimental measurement, mechanistic and theoretical models, to the role of small cracks in fretting fatigue and the application of small crack results to the aging aircraft and high-cycle fatigue problems, are covered.

Author : Wataru Kanematsu
Publisher :
Page : 20 pages
File Size : 50,21 MB
Release : 2012
Category : Balls-on-flat
ISBN :

GET BOOK

Crack propagation behavior prior to flaking in rolling contact fatigue (RCF) tests has been analyzed by microscopic observation to gain insight into the mechanism for final spall of specimen. Balls-on-flat RCF tests under constant and stepwise load were carried out for three bearing grade silicon nitrides and one general purpose one at several stress levels. Detailed observations of crack propagation on a contact track during tests under constant load reveal that a linear crack, which shows up just outside of the track, grows at both ends of the crack with an increase in stress cycles. This growth, opposite to the rolling direction, eventually leads to the formation of hook-like cracks. Immediately before spalling, a major hook-like crack and associated arc-like cracks are formed. From the surface and section views of spalled regions of the specimens tested under stepwise load, we found supporting evidence for the hypothesis that major crack growth inclined toward the rolling direction forming at the bottom surface of the spall, with subsequent upward crack growths from the major crack and associated arc-like ones on the specimen surface, eventually developing into a crack network leading to the dislodging of fragments.

Author : Michael R. Mitchell
Publisher : ASTM International
Page : 405 pages
File Size : 28,56 MB
Release : 1994
Category : Composite materials
ISBN : 0803119895

GET BOOK

Examines the initiation and growth of fatigue cracks and the fracture toughness of advanced materials such as silicon nitride, special alloys and steels, thermoplastics, and graphite-epoxy composites; and explains several non-destructive techniques to evaluate such materials for manufacturing defect

Author : Rawley Brandon Greene
Publisher :
Page : 118 pages
File Size : 27,43 MB
Release : 2013
Category : Silicon nitride
ISBN :

GET BOOK

Because of its attractive material properties like high hardness, high toughness, and excellent high temperature strength, materials like silicon nitride are becoming more common for use in high performance applications. However, there have been limited studies of the fatigue behavior of small cracks in silicon nitride and other materials toughened by grain bridging mechanisms. This study explores using micro Raman spectroscopy, fatigue crack growth data and results from static fracture experiments to determine a bridging stress profile for silicon nitride doped with MgO and Y2O3 as sintering additives. These bridging stress profiles allow for the creation of a geometry specific fatigue threshold R-curve which can be used to develop a fatigue endurance strength prediction tool to aid in the design of products using the material. Cyclical fatigue experiments conducted on bend beams with induced semi-elliptical surface cracks were conducted to verify the prediction tool. The results show that no bend beams with this crack geometry failed below the predicted endurance level. It is expected that this method can be extended to create fatigue endurance strength predictions for other materials similarly toughened by grain bridging and other mechanisms.

Author : R.C. Bradt
Publisher : Springer Science & Business Media
Page : 592 pages
File Size : 11,40 MB
Release : 2012-12-06
Category : Technology & Engineering
ISBN : 1461533503

GET BOOK

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.

Author : R. C. Bradt
Publisher : Springer
Page : 522 pages
File Size : 38,34 MB
Release : 1978-03-31
Category : Science
ISBN :

GET BOOK

These volumes, 3 and 4, of Fracture Mechanics of Ceramics con stitute the proceedings of an international symposium on the frac ture mechanics of ceramics held at the Pennsylvania State Univer sity, University Park, PA on July 27, 28, and 29, 1977. Volumes 1 and 2 were published previously as the proceedings of a sympo sium of the same name held July 11, 12, and 13, 1973, also at Penn State. All four volumes published to date concentrate on the fracture aspects of the mechanical behavior of brittle'ceramics in terms of the characteristics of cracks. The program chairmen gratefully acknowledge the financial as sistance for the symposium provided by the Office of Naval Re search, the Energy Research and Development Administration, and the Army Research Office. Without their support the quality and mag nitude of this conference simply would not have been possible. Numerous individuals contributedto the success of the con ference, but unfortunately they cannot all be listed here. However the program chairmen would especially like to recognize the contri butions of Penn State Conference Coordinator, Mr. Ronald Avillion, whose expertise in planning and organization was indispensable; Dr. Fred R. Matson for his interesting after dinner speech; and Drs. A. M. Diness, J. C. Hurt, and D. W. Readey for their en couragement and valuable suggestions regarding the program. Finally, we wish to also thank our joint secretaries for the patience and help in bringing these proceedings to press.