Fatigue and Fracture - Böcker

More than six years ago, several of Rabotnov's close friends and colleagues from the USSR and USA decided to contribute a volume on Plasticity and Failure of Solids in honor of his 70th birthday. The celebration was interrupted unexpectedly by his death on May 13, 1985 at which time another decision was made still to publish the work, but as a memorial volume. As in any field of scientific endeavor, research confronts the scientists with anomalies; our chosen area is no exception. The ways in which failure criteria and plasticity theory are combined can differ widely among the researchers; they will never yield quite the same results. Each of the invited contributors has, therefore, been encouraged to express his views and to expound on his personal opinion. The contributors are free of enumeration from the authority and/or consensus of any scientific society or community. What impedes scientific process is the esoteric tradition of accepting ideas and theories by consensus among members of societies and communities. The absence of such a trend is refreshing; the collaboration between the authors from the USSR and the USA had to be one of the contributing factors. Finally, the editors wish to acknowledge the authors who have made the publication of this volume possible. a. c. Sib S. T. Mileiko AJ. Ishlinsky xi The late Professor Yuriy Nickolaevich Rabotnov (February 24, 1914 - May 13, 1985) xii Scientific biography of the late academician Yu. N.

Within the last two decades fracture theory has been one of the most rapidly advancing fields of continuous media mechanics. Noteworthy suc­ cess has been achieved in linear fracture mechanics where the propagation of the macrocrack in elastic materials is under study. However, fracture of materials is by no means a simple process since it involves fracture of structural elements ranging from atomic sizes to macrocracks. To obtain all information about how and why materials fail, all stages of the process must be studied. For a long time both mechanical engineers and physicists have been concerned with the problem of the fracture of solids. Unfortunately, most of their work has been independent of the others. To solve the problem not only requires the minds and work of mechanical engineers and physicists but chemists and other specialists must be consulted as well. In this book we will consider some conclusions of the "physical" and "mechanical" schools acquired by the A. F. Joffe Physics-Technical Institute of the USSR Academy of Sciences in Leningrad and the Institute of Polymer Mechanics of Latvian SSR Academy of Sciences in Riga. The methods for studying the phenomena of fracture applied at both Institutes are different yet complimentary to one another; the materials tested are also sometimes different.

The studies on the phenomena of fatigue in metals, and especially on the formation and growth rate of cracks have been conducted in 1972-1974 with continued intensity. Their results contribute to expanding our knowledge and give us a new insight into the sphere of metal fatigue which is a highly interdiscipline field. This makes the continuous amending and modifying of books on metal fatigue a necessity, unfortunately often related with the not easy task of changing one's opinions and critical analysis of established earlier notions. These aims were my chief concern when preparing the present edition of my book in which I made use of carefully selected new information from 1972-1973 and partly 1974 reports. This new matter has been included in many instances just to signal new facts or findings, since the limited space did not allow me to give them the amount of consideration they deserve. The book has been further supplemented with the results of micrographic studies conducted in co-operation with J. Kozubowski for which lowe him special thanks. I am also indebted to Mr. H. Mughrabi from Stuttgart for allowing me to publish in this book his very interesting micrographs of dislocation structures. Finally I should like to express my sincere thanks to Mr. E. Lepa for his concern in producing a good English translation of my book.

Within the last two decades fracture theory has been one of the most rapidly advancing fields of continuous media mechanics. Noteworthy suc­ cess has been achieved in linear fracture mechanics where the propagation of the macrocrack in elastic materials is under study. However, fracture of materials is by no means a simple process since it involves fracture of structural elements ranging from atomic sizes to macrocracks. To obtain all information about how and why materials fail, all stages of the process must be studied. For a long time both mechanical engineers and physicists have been concerned with the problem of the fracture of solids. Unfortunately, most of their work has been independent of the others. To solve the problem not only requires the minds and work of mechanical engineers and physicists but chemists and other specialists must be consulted as well. In this book we will consider some conclusions of the "physical" and "mechanical" schools acquired by the A. F. Joffe Physics-Technical Institute of the USSR Academy of Sciences in Leningrad and the Institute of Polymer Mechanics of Latvian SSR Academy of Sciences in Riga. The methods for studying the phenomena of fracture applied at both Institutes are different yet complimentary to one another; the materials tested are also sometimes different.

The studies on the phenomena of fatigue in metals, and especially on the formation and growth rate of cracks have been conducted in 1972-1974 with continued intensity. Their results contribute to expanding our knowledge and give us a new insight into the sphere of metal fatigue which is a highly interdiscipline field. This makes the continuous amending and modifying of books on metal fatigue a necessity, unfortunately often related with the not easy task of changing one's opinions and critical analysis of established earlier notions. These aims were my chief concern when preparing the present edition of my book in which I made use of carefully selected new information from 1972-1973 and partly 1974 reports. This new matter has been included in many instances just to signal new facts or findings, since the limited space did not allow me to give them the amount of consideration they deserve. The book has been further supplemented with the results of micrographic studies conducted in co-operation with J. Kozubowski for which lowe him special thanks. I am also indebted to Mr. H. Mughrabi from Stuttgart for allowing me to publish in this book his very interesting micrographs of dislocation structures. Finally I should like to express my sincere thanks to Mr. E. Lepa for his concern in producing a good English translation of my book.