Book Review

This book, largely, is based on the author's research leading to a PhD at the University of Wales at Swansea under the supervision of Professors D.R.J. Owen and N. Bicanic and was supported on an EPSRC contract.

The book covers adequately the computational mechanics continua and discontinua, in which particle-based modelling of the microstructural elements of the materials has been given due credit. Chapter 1 gives the basis for density versus distance of microelements such as packages of spheres in boxes. The procedures for the evaluation of contact forces, motion sequence and energy-time relation are given in chapter 2. The methodology of computing stress-strain tensors using a constitutive law have been well attempted in chapter 4 while giving an introduction in chapter 3, the algorithms of particle size used in contact detection. Chapter 5 is devoted to the dynamics of irregular discrete elements. Central difference and explicit time integration have been chosen for the dynamic analysis of a box full of pebbles. Analytical results supported by graphical interpretations are included from the initial motion to pirouetting. The author is emphatic on these known methods as an alternative for the determination of amplification factors and periodic error. The bouncing pack in different positions is the main theme of the sensitivity of this method.

The transition of continua to discontinua using softened smear fracture has now been promoted using the discrete element approach in chapter 7. The author then turns towards the application of this method to fluid coupling in chapter 8 and gas flow through fractured solids and CFDE element simulation computation in chapter 9. Chapter 10 gives some of the core algorithms which are based on C-based implementation.

Unfortunately, the pioneers in this research have been excluded from the 300 odd references given in the text, especially the recent London University research thesis "The combined finite/discrete element method in transient dynamics of r.c. structures under blast loading" (Queen Mary, London University, 2004).

The contact element presented is devoid of sophistication when compared to those given by the famous finite element packages such as ANYS, ABACUS, NASTRAN etc. which have large user groups and which are worldwide. NO mesh generation scheme is included with this approach. No practical case studies are included to attract engineers, particularly structural engineers.

The combined finite-discrete element method is in it's embryonic stage and requires further research and development in order to compete with the existing voluminous FORTRAN packages in the market in which billions have been spent already. Structural engineers must pay attention to the little use of this method for concrete and steel structures. The method, at present, can be used for problems in rock mechanics and flow of dense granular systems in silos and hoppers.

The price is too high unless it is supported by a CD-ROM. The publishers are known for quality production and excellence as are visible in this book.

M.Y.H. Bangash