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 contributed to 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."

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."

These volumes constitute the Proceedings of a Symposium ort the Fracture Mechanics of Cerarnics, held at the Pennsylvania State University, University Park, Pennsylvania, July 11, 12, and 13, 1973. The theme of the symposium focussed on the mechanical behavior of brittle cerarnics in terms of the characteristics of cracks. The 52 contributed papers by 87 authors, present an overview of the cur rent understanding of the theory and application of fracture mechan ics to brittle cerarnics. The prograrn chairmen gratefully acknowledge the financial assistance for the Symposium provided by the Office of Naval Re search, the College of Earth and Mineral Sciences of the Pennsyl vania State University, the Materials Research Center of Lehigh University, Bethlehem, Pennsylvana and Westinghouse Research Laboratories, Pittsburgh, Pennsylvania. Special appreciation is extended to the expert organization provided by the J. Orvis Keller Conference Center of the Pennsyl vania State Conference Center of the Pennsylvania State University. In particular, Mrs. Patricia Ewing should be acknowledged for the excellent prograrn organization and planning. Dean Harold J. O'Brien, who was featured as the after-dinner speaker and who presented a most stimulating talk on the cornrnunication between people, also contrib uted to the success of the meeting. Finally, we also wish to thank our joint secretaries for the patience and help in bringing these Proceedings to press. University Park R. C. Bradt Bethlehem D. P. H. Hasseiman Pittsburgh, Pennsylvania F. F. Lange July, 1973 v CONTENTS OF VOLUME 2 Contents of Volume 1 . . . . . . . . . . . . . . . . . . .

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 National 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.

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.

These volumes, 5 and 6, of Fracture Mechanics of Ceramics constitute the proceedings of an international symposium on the fracture mechanics of ceramic materials held at The Pennsylvania State University, University Park, PA on July 15, 16, and 17, 1981. These proceedings constitute the third pair of volumes of a con tinuing series of conferences. Volumes 1 and 2 were from the 1973 symposium and volumes 3 and 4 from a 1977 symposium, both of which were also held at Penn State. The theme of this conference, as the previous two, 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 Army Research Office, the National Science Foundation, and the Office of Naval Research. Without their support, the magnitude and quality of this conference simply would not have been possible.