Vito N. Ghionna – författare

Modelling of granular and porous materials in science and engineering touches all kinds of problems arising from the necessity to successfully describe the behaviour of materials naturally existing in our surroundings. The book brings together scientists in engineering and mathematicians interested in solid behaviour and experts in particulate material modelling. The modelling process is a critical tool for studying the analysis and experimentation of micromechanics and behavior of granular and porous material. The text focuses upon the most important techniques and models currently in use, looking at: mechanics of porous media; modelling of soil behaviour; flow and transport phenomena in particulate materials; numerical simulation methods; and numerical model for finite elastoplastic deformations. The text should appeal to research workers, graduate students, and scientists in applied mathematics, continuum mechanics, finite element methods, solid mechanics and hydraulics engineering.

Soils are complex materials: they have a particulate structure and fluids can seep through pores, mechanically interacting with the solid skeleton. Moreover, at a microscopic level, the behaviour of the solid skeleton is highly unstable. External loadings are in fact taken by grain chains which are continuously destroyed and rebuilt. Many issues of modeling, even of the physical details of the phenomena, remain open, even obscure; de Gennes listed them not long ago in a critical review. However, despite physical complexities, soil mechanics has developed on the assumption that a soil can be seen as a continuum, or better yet as a medium obtained by the superposition of two and sometimes three con­ and the other fluids, which occupy the same portion of tinua, one solid space. Furthermore, relatively simple and robust constitutive laws were adopted to describe the stress-strain behaviour and the interaction between the solid and the fluid continua. The contrast between the intrinsic nature of soil and the simplistic engi­ neering approach is self-evident. When trying to describe more and more sophisticated phenomena (static liquefaction, strain localisation, cyclic mo­ bility, effects of diagenesis and weathering, ..... ), the nalve description of soil must be abandoned or, at least, improved. Higher order continua, incrementally non-linear laws, micromechanical considerations must be taken into account. A new world was opened, where basic mathematical questions (such as the choice of the best tools to model phenomena and the proof of the well-posedness of the consequent problems) could be addressed.