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Recent advances in non-linear computational mechanics
BOOK R EVIEWS Recent Advances in Non-linear Computational Mechanics Edited by E. Hinton, D. R. J. Owen and C. Taylor Pineridge Press Limited, Swansea, UK This excellent volume provides a comprehensive review of the recent research in non-linear computational mechanics. The reviewer believes that anyone desiring to seek a numerical solution of non-linear mechanics problems will benefit immensely by studying the book. Each one of the ten chapters in the book has been written by an eminent researcher. The authors have summarised the current state of the knowledge in their respective areas of research and have provided an extensive list of references. Some prior understanding of the basics of linear elasticity, plasticity and the finite element method has been presumed of the reader. The four chapters by M. A. Crisfield, P. G. Bergen, T. J. R. Hughes, A. F. Elsawaf and B. M. Irons deal with different methods of solving a system of non-linear algebraic equations. The relative advantages and disadvantages of various techniques to analyse the snap through problem, postbuckling behavior of structures, transient problems and elastoplastic problems are described. The article by J. C. Nagtegaal summarises many equivalent versions of the principle of virtual power for non-linear problems involving materials with rate type constitutive relations. These formulations are especially useful to study problems wherein the expected strains and/or rotations are very large. E. Ramm has discussed how prescribed essential boundary conditions can be used to control the load increments in a non-linear problem. F. G. Rammerstorfer has applied the catastrophe theory to study the stability of geometrically non-linear structural problems. The comprehensive article on geometrically non-linear composite plates by J. N. Reddy compares lucidly the performance of various finite elements both with and without the use of reduced integration. A few algorithms to trace to sub- and postcriticat equilibrium paths for non-linear eccentricity stiffened wide panels have been reviewed by G. Ise. D. J. R. Owen and F. Damjanic have discussed the use of stability arguments to find out the optimum time increment for viscoplastic problems. As a whole the book contains a wealth of information. All technical libraries should own a copy of the book. It is highly recommended for researchers working or contemplating to work in non-linear computational mechanics.
R. C. Batra Department of Engineering Mechanics, University of Missouri-Rolla, USA
Comal Handbook Len Lindsay Reston Publishing Co., March 1983, 310 pp., £16.10. ISBN 0-8359-0878-X The book is concerned with the instruction set of the language COMAL (Common Algorithm Language). The language was designed in 1973 to be used on the Commodore PET computers, in an effort to combine the simplicity of BASIC and the power of PASCAL. The description of the in~'ruction set is performed by use of a dictionary format. The commands are set out in alphabetical order, with the description for each new command being laid out on a new page. A set format is followed for each command, with the following information being given: (1) Command name; (2) Category of command; (3) Language standards which
incorporate this command; (4) Explanation of command; (5) Notes on the command; (6) Syntax for command usage; (7) Examples of usage; (8) Sample program containing the command. The appendices in the book deal with programming structures and techniques in COMAL including the coding for a number of sample procedures and functions for the use of the reader. The overall structure of the book is easily understandable, with an initial section detailing the terminology and format used in the sections to follow. The correct forms for file and variable naming convertions are covered in this section. This section enables the following descriptions for each command to be easily followed and understood. The reader is also informed of any differences which may exist from one language release to another, for each of the language commands. However, there is one notable exclusion from the book. Although there is a code listing of an error message generator, no facility is given for the reader to refer to a comprehensive list of error messages, to ease the process of program development. Hence, for use as a programming language handbook, the book is extremely well planned and laid out, with sufficient information being provided in an uncomplicated form. As with nearly all language handbooks, this book requires a certain amount of programming familiarity on the part of the user to be used quickly and efficiently. Due to the alphabetic structure of the command descriptions, it would not be straightforward for a complete novice to learn the language from this book from first principles. However, programmers with a limited amount of computational experience should be able to learn the language of COMAL without too many problems, and, as the author states in the introduction, a programming language will be understood much faster by using the language than just reading about it.
Andrew Mercey Computational Mechanics, Southampton, UK
Computational Hydraulics Brebbia and Ferrante The Butterworth Group, March 1983, £20, ISBN 408011 53 X This book covers most aspects of fluid flow for engineers, with a strong bias towards methods of solution. Similar to
Computational Methods for the Solution of Engineering Problems, the book presents computer programs written in FORTRAN, for use in the solution of each major topic covered by the book. The first two chapters introduce the essential concepts of fluid flow in a way which is easily read and understood, the next two chapters cover most aspects of flow in pipes including two programs for the solution of pipe networks. In the authors' customary fashion the programs are neatly documented and are thoroughly tested. The similarities between the programs here and elsewhere serving only to reinforce ones understanding of the finite element technique. Chapter 5 covers open channel flow in a brief but concise manner with more FORTRAN code for the calculation of depth of flow. In Chapter 6 two computer programs for the solution of the Laplace equation are g i v e n - one using finite elements and the other using a more efficient and innovative technique using Boundary elements. The final chapters cover the more advanced concepts of the Navier-Stokes equations and Turbomachinery. In conclusion Computational Hydraulics is written in a very concise style which is also very readable, the advanced nature of the text being shrouded by the apparent ease with which it explains each topic.
Paul Tugwell
Adv. Eng. Software, 1984, Vol. 6, No. 1
61
R. C. Batra Department of Engineering Mechanics, University of Missouri-Rolla, USA
Comal Handbook Len Lindsay Reston Publishing Co., March 1983, 310 pp., £16.10. ISBN 0-8359-0878-X The book is concerned with the instruction set of the language COMAL (Common Algorithm Language). The language was designed in 1973 to be used on the Commodore PET computers, in an effort to combine the simplicity of BASIC and the power of PASCAL. The description of the in~'ruction set is performed by use of a dictionary format. The commands are set out in alphabetical order, with the description for each new command being laid out on a new page. A set format is followed for each command, with the following information being given: (1) Command name; (2) Category of command; (3) Language standards which
incorporate this command; (4) Explanation of command; (5) Notes on the command; (6) Syntax for command usage; (7) Examples of usage; (8) Sample program containing the command. The appendices in the book deal with programming structures and techniques in COMAL including the coding for a number of sample procedures and functions for the use of the reader. The overall structure of the book is easily understandable, with an initial section detailing the terminology and format used in the sections to follow. The correct forms for file and variable naming convertions are covered in this section. This section enables the following descriptions for each command to be easily followed and understood. The reader is also informed of any differences which may exist from one language release to another, for each of the language commands. However, there is one notable exclusion from the book. Although there is a code listing of an error message generator, no facility is given for the reader to refer to a comprehensive list of error messages, to ease the process of program development. Hence, for use as a programming language handbook, the book is extremely well planned and laid out, with sufficient information being provided in an uncomplicated form. As with nearly all language handbooks, this book requires a certain amount of programming familiarity on the part of the user to be used quickly and efficiently. Due to the alphabetic structure of the command descriptions, it would not be straightforward for a complete novice to learn the language from this book from first principles. However, programmers with a limited amount of computational experience should be able to learn the language of COMAL without too many problems, and, as the author states in the introduction, a programming language will be understood much faster by using the language than just reading about it.
Andrew Mercey Computational Mechanics, Southampton, UK
Computational Hydraulics Brebbia and Ferrante The Butterworth Group, March 1983, £20, ISBN 408011 53 X This book covers most aspects of fluid flow for engineers, with a strong bias towards methods of solution. Similar to
Computational Methods for the Solution of Engineering Problems, the book presents computer programs written in FORTRAN, for use in the solution of each major topic covered by the book. The first two chapters introduce the essential concepts of fluid flow in a way which is easily read and understood, the next two chapters cover most aspects of flow in pipes including two programs for the solution of pipe networks. In the authors' customary fashion the programs are neatly documented and are thoroughly tested. The similarities between the programs here and elsewhere serving only to reinforce ones understanding of the finite element technique. Chapter 5 covers open channel flow in a brief but concise manner with more FORTRAN code for the calculation of depth of flow. In Chapter 6 two computer programs for the solution of the Laplace equation are g i v e n - one using finite elements and the other using a more efficient and innovative technique using Boundary elements. The final chapters cover the more advanced concepts of the Navier-Stokes equations and Turbomachinery. In conclusion Computational Hydraulics is written in a very concise style which is also very readable, the advanced nature of the text being shrouded by the apparent ease with which it explains each topic.
Paul Tugwell
Adv. Eng. Software, 1984, Vol. 6, No. 1
61