**Basil **homepage at Leeds University

Basil is a finite element program which calculates quantities which describe stress and strain in non-linear viscous materials, for strains up to the of order 100%. The calculations describe very viscous Earth materials which undergo irreversible large-strain deformation at high temperature and over long time periods, under the influence of body forces and surface tractions.

The program permits a spatially variable Newtonian or non-Newtonian viscosity in a 2-D geometry with boundary conditions on traction and/or velocity. It is also possible to include a single fault or discontinuity in the problem in a dynamically self consistent way. The 2-D deformation field represents either plane-strain deformation, or it permits a specified distribution of normal stress in the third direction. The latter is referred to as the thin viscous sheet formulation when the normal force is due to gravity acting on variations of the layer thickness. Plane-stress calculations are a specific case of the thin viscous sheet formulation.

The programs basil and sybil have been developed mainly at Monash University since 1988, and before that at ANU and Harvard. The present set of programs has been developed mainly by Greg Houseman, Terence Barr and Lynn Evans. Important contributions by others, particularly by Philip England during the early stages of development are gratefully acknowledged. Comments on, or questions about, basil and sybil should be sent to greg@earth.leeds.ac.uk

A User Manual which gives background theory and worked examples of finite deformation problems solved using basil is under development.

Last Updated on Wednesday, 05 July 2006 18:33