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Composite materials; mechanics, mechanical properties and fabrication
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Applied Mechanics: Dynamics, Second Edition, by Charles E. Smith, Wiley, New York and Toronto, 1982. ISBN 0-471-02965-3, xvii + 518 pages, illustrated, hard cover, £16.85. This is n o t a new book: the first edition has been published for some six years and the book under review is a recent edition. Also, it is intended to be studied after the companion volume in Statics: as the author points out, Dynamics is more difficult than Statics. Certainly, to a teacher of Applied Mechanics, it is refreshing to see the subjects of Statics and Dynamics treated consecutively rather than simultaneously. Further, the author places strong emphasis on the conceptual view of dynamics and this is important because much of engineering is intuitive in the first place. Consequently the book does n o t concentrate too early on economical analytical techniques -- such as formal vector algebra -- which though essential for a proper treatment, can mask some of the basic ideas and inhibit a "feeling" for the subject. A full range of Dynamics is covered -- up to Honours Degree level in Mechanical Engineering or Aeronautical Engineering -- and the tutorial examples are up to date. The presentation of the book is first class -- a standard of quality we have come to expect from Wiley since the publication of their Statics and Dynamics by J.L. Meriam, a book which did for Applied Mechanics what Rogers and Mayhew did for Thermodynamics. In short, this is a thoroughly good book, giving a m o d e m treatment to its subject, and it will appeal to both teachers and students of Dynamics at Honours level. N. MAW
Composite Materials; Mechanics, Mechanical Properties and Fabrication, by Kozo Kawata and Takashi Akasaka (Eds.), Applied Science, Barking, Essex, 1982. ISBN 0-85334-144-3, xi + 562 pages, 80 tables, 571 illustrations, hard cover £34.00. If today's engineering student needs to be a production man, the world in which he has chosen to forge himself a living is filled not only with a bewildering number of processes but also with an equally great number of materials, all under constant modification. Perhaps the most rapidly maturing technology with emerging applications is in the field of composite materials with its increasingly attractive, ever-broadening group of related industries. The trend in virtually everything that is man-made today is that it should be - as appropriate -- faster, lighter, stronger, more efficient, more elegant and longer lasting. Yet the engineer can only design components/equipment within the parameters of the materials available: hence the importance of developing even newer materials that can withstand more severe working conditions and yet retain tighter tolerances. All this sounds very attractive
99
indeed: where then is the problem? In the reviewer's opinion, the main problem associated with introducing a new generation of engineering materials is to educate a large number of engineers. To the best knowledge of the reviewer, the engineering curricula in the universities and the polytechnics of the U.K., for example, have not yet been sufficiently revised to accommodate composite technology such that "specialised engineers" (in terms of an appropriate background in the analysis, design, fabrication of structures, mechanical devices for processing, and development of new composites) are readily available to respond to the obvious demand*. Those who are working in this field might have had only a preliminary, undergraduate-level course followed by either a postgraduate degree or a more specialised research topic carried out within the four walls of a laboratory. In addition, the topic of composite materials is so heterogeneous that the conventional textbook-type of approach may give rise to serious limitations. Short courses, seminars, conferences, etc. can therefore be of great help (if not by direct attendance then through proceedings), since real progress on this topic depends on continued, independent study and research. The present book -- the proceedings of a Japan--U.S.A. conference on composite materials held in Tokyo in 1981 -- is yet another volume which should help those specialised engineers and material scientists who have been, so-to-say, continuing their education. The scope of this conference was concentrated upon mechanics, mechanical properties and fabrication, in particular of household articles, automobiles, trains, rockets and artificial satellites. Fifty-eight papers on almost all types of composites, contributed by wellknown experts from Japan and the U.S.A., were grouped under the following main sessions: Dynamic Behaviour and Wave Propagation; Stress Analysis and Mechanical Properties; Fatigue Properties; Fracture and Strength of Composites; Metal Matrix (and Mortar) Composites; Ceramics and Rubber Composites; Thermal and Environmental Problems; Strength of Structural Elements; Design and Applications (and Education); Overview of Composites. "Engineering educators who are typically conservative and do not respond rapidly to changes in their environment" are urged to read the interesting and thought-provoking papers that were presented under the last two session headings: these essentially included suggestions as to how an integration of composite materials into the main-stream of traditional engineering education can be made and courses modified to incorporate composite topics in parallel with similar metal topics.
*According to Drucker (Wall Street J., March 3, 1981, p. 22) "Demand for education is actually going up, not down. What is going down, and fairly fast, is demand for traditional education in traditional schools". He additionally observes that "the fastest growing industry in America today may be the continuing professional education of highlyschooled mid-career adults" and "we face an all but insatiable demand for advanced professional education".
100 The quality of production o f this useful reference work is in accordance with the high standard to which one is accustomed from Applied Science Publishers. S.K. GHOSH
Vibrations of Shells and Plates, by Werner Soedel, Marcel Dekker, New York, 1981. ISBN 0-8247-1193-9, xiv + 366 pages, illustrated, hard cover Sfr. 136.00. Manufacturers looking for a competitive edge in today's hard e c o n o m y have almost without exception tried to b o o s t productivity by increasing machine speeds and by using lighter, less costly materials. Whilst this has led to a surprising improvement in output, coupled with reduction of costs for many types of products -- vehicles and machinery, and various industrial structures including nuclear power plant and bridges -- the potential benefits of these changes have often been reduced by the vibrations they create. In general, two different phases of analysis are employed to "qualify" equipment and structures: (i) dynamic forces are analysed to establish the inertial forces that are acting on them, and (ii) stresses are analysed to determine that they will n o t fail. A piece of equipment (or a structure) is first modelled mathematically as a multi-degree-of-freedom system with, for example, lumped masses, and springs and dampers, if any. The second step in the dynamic analysis is to find the lowest natural frequencies o f the body, the magnitude of which essentially determine the extent of the dynamic input and the associated "flexing". There are many t e x t b o o k s available which describe the usual methods and solution-procedures of vibration. Unfortunately, most of these texts cover mainly beams and beam-like structures and their vibration. It is probably because of their simplicity in shape and mathematical formulation that demonstration problems and solutions in most t e x t b o o k s are based upon beams -in particular, upon cantilever beams, which admittedly have a very wide range of engineering applications. Some of these books on the dynamics of structures treat, to some extent, the vibration of plates. The topics of the vibrations of shells and plates (and shell-like elements) have, however, not been treated extensively in textbooks, apart from, for example, the classic monographs of A. Leissa (Vibration of Plates, NASA SP-160, 1969, and Vibration of Shells, NASA SP°288, 1973) and, more recently, by E.B. Magrab (Vibration of Elastic Structural Members, Sijthoff and Noordhoff, 1979). It is n o t always beams which vibrate however, and in this respect Professor Soedel's b o o k on the vibration of shells and plates is a welcome addition -for students and teachers, in particular -- to fill the gap. The b o o k is of slight-
Applied Mechanics: Dynamics, Second Edition, by Charles E. Smith, Wiley, New York and Toronto, 1982. ISBN 0-471-02965-3, xvii + 518 pages, illustrated, hard cover, £16.85. This is n o t a new book: the first edition has been published for some six years and the book under review is a recent edition. Also, it is intended to be studied after the companion volume in Statics: as the author points out, Dynamics is more difficult than Statics. Certainly, to a teacher of Applied Mechanics, it is refreshing to see the subjects of Statics and Dynamics treated consecutively rather than simultaneously. Further, the author places strong emphasis on the conceptual view of dynamics and this is important because much of engineering is intuitive in the first place. Consequently the book does n o t concentrate too early on economical analytical techniques -- such as formal vector algebra -- which though essential for a proper treatment, can mask some of the basic ideas and inhibit a "feeling" for the subject. A full range of Dynamics is covered -- up to Honours Degree level in Mechanical Engineering or Aeronautical Engineering -- and the tutorial examples are up to date. The presentation of the book is first class -- a standard of quality we have come to expect from Wiley since the publication of their Statics and Dynamics by J.L. Meriam, a book which did for Applied Mechanics what Rogers and Mayhew did for Thermodynamics. In short, this is a thoroughly good book, giving a m o d e m treatment to its subject, and it will appeal to both teachers and students of Dynamics at Honours level. N. MAW
Composite Materials; Mechanics, Mechanical Properties and Fabrication, by Kozo Kawata and Takashi Akasaka (Eds.), Applied Science, Barking, Essex, 1982. ISBN 0-85334-144-3, xi + 562 pages, 80 tables, 571 illustrations, hard cover £34.00. If today's engineering student needs to be a production man, the world in which he has chosen to forge himself a living is filled not only with a bewildering number of processes but also with an equally great number of materials, all under constant modification. Perhaps the most rapidly maturing technology with emerging applications is in the field of composite materials with its increasingly attractive, ever-broadening group of related industries. The trend in virtually everything that is man-made today is that it should be - as appropriate -- faster, lighter, stronger, more efficient, more elegant and longer lasting. Yet the engineer can only design components/equipment within the parameters of the materials available: hence the importance of developing even newer materials that can withstand more severe working conditions and yet retain tighter tolerances. All this sounds very attractive
99
indeed: where then is the problem? In the reviewer's opinion, the main problem associated with introducing a new generation of engineering materials is to educate a large number of engineers. To the best knowledge of the reviewer, the engineering curricula in the universities and the polytechnics of the U.K., for example, have not yet been sufficiently revised to accommodate composite technology such that "specialised engineers" (in terms of an appropriate background in the analysis, design, fabrication of structures, mechanical devices for processing, and development of new composites) are readily available to respond to the obvious demand*. Those who are working in this field might have had only a preliminary, undergraduate-level course followed by either a postgraduate degree or a more specialised research topic carried out within the four walls of a laboratory. In addition, the topic of composite materials is so heterogeneous that the conventional textbook-type of approach may give rise to serious limitations. Short courses, seminars, conferences, etc. can therefore be of great help (if not by direct attendance then through proceedings), since real progress on this topic depends on continued, independent study and research. The present book -- the proceedings of a Japan--U.S.A. conference on composite materials held in Tokyo in 1981 -- is yet another volume which should help those specialised engineers and material scientists who have been, so-to-say, continuing their education. The scope of this conference was concentrated upon mechanics, mechanical properties and fabrication, in particular of household articles, automobiles, trains, rockets and artificial satellites. Fifty-eight papers on almost all types of composites, contributed by wellknown experts from Japan and the U.S.A., were grouped under the following main sessions: Dynamic Behaviour and Wave Propagation; Stress Analysis and Mechanical Properties; Fatigue Properties; Fracture and Strength of Composites; Metal Matrix (and Mortar) Composites; Ceramics and Rubber Composites; Thermal and Environmental Problems; Strength of Structural Elements; Design and Applications (and Education); Overview of Composites. "Engineering educators who are typically conservative and do not respond rapidly to changes in their environment" are urged to read the interesting and thought-provoking papers that were presented under the last two session headings: these essentially included suggestions as to how an integration of composite materials into the main-stream of traditional engineering education can be made and courses modified to incorporate composite topics in parallel with similar metal topics.
*According to Drucker (Wall Street J., March 3, 1981, p. 22) "Demand for education is actually going up, not down. What is going down, and fairly fast, is demand for traditional education in traditional schools". He additionally observes that "the fastest growing industry in America today may be the continuing professional education of highlyschooled mid-career adults" and "we face an all but insatiable demand for advanced professional education".
100 The quality of production o f this useful reference work is in accordance with the high standard to which one is accustomed from Applied Science Publishers. S.K. GHOSH
Vibrations of Shells and Plates, by Werner Soedel, Marcel Dekker, New York, 1981. ISBN 0-8247-1193-9, xiv + 366 pages, illustrated, hard cover Sfr. 136.00. Manufacturers looking for a competitive edge in today's hard e c o n o m y have almost without exception tried to b o o s t productivity by increasing machine speeds and by using lighter, less costly materials. Whilst this has led to a surprising improvement in output, coupled with reduction of costs for many types of products -- vehicles and machinery, and various industrial structures including nuclear power plant and bridges -- the potential benefits of these changes have often been reduced by the vibrations they create. In general, two different phases of analysis are employed to "qualify" equipment and structures: (i) dynamic forces are analysed to establish the inertial forces that are acting on them, and (ii) stresses are analysed to determine that they will n o t fail. A piece of equipment (or a structure) is first modelled mathematically as a multi-degree-of-freedom system with, for example, lumped masses, and springs and dampers, if any. The second step in the dynamic analysis is to find the lowest natural frequencies o f the body, the magnitude of which essentially determine the extent of the dynamic input and the associated "flexing". There are many t e x t b o o k s available which describe the usual methods and solution-procedures of vibration. Unfortunately, most of these texts cover mainly beams and beam-like structures and their vibration. It is probably because of their simplicity in shape and mathematical formulation that demonstration problems and solutions in most t e x t b o o k s are based upon beams -in particular, upon cantilever beams, which admittedly have a very wide range of engineering applications. Some of these books on the dynamics of structures treat, to some extent, the vibration of plates. The topics of the vibrations of shells and plates (and shell-like elements) have, however, not been treated extensively in textbooks, apart from, for example, the classic monographs of A. Leissa (Vibration of Plates, NASA SP-160, 1969, and Vibration of Shells, NASA SP°288, 1973) and, more recently, by E.B. Magrab (Vibration of Elastic Structural Members, Sijthoff and Noordhoff, 1979). It is n o t always beams which vibrate however, and in this respect Professor Soedel's b o o k on the vibration of shells and plates is a welcome addition -for students and teachers, in particular -- to fill the gap. The b o o k is of slight-