Nonlinear Finite Element Analysis
The geotechnical group has developed an extensive suite of software for performing elastoplastic finite element analysis, and this is continually being expanded. Due to the complex numerical issues involved, nonlinear analysis of geotechnical problems has traditionally been the domain of specialists with relatively few calculations being performed by practising engineers. A novel feature of the Newcastle finite element code, SNAC, is its focus on automating the process of nonlinear analysis by the use of intelligent algorithms. This permits powerful methods to be applied in a rational and less error prone way. Over the past decade, considerable progress has been made on this topic, and the algorithms developed here are now employed in many industrial finite element codes.
SNAC incorporates a wide range of elastoplastic soil models, including those belonging to the critical state family, and has advanced algorithms for stress integration, load stepping, and time stepping (in consolidation analysis). All of these procedures are implemented with automatic error control and are able to provide accurate solutions for highly nonlinear soil models. SNAC also incorporates a sophisticated macro language that permits users to design their own solution algorithms. This feature is valuable in research environments, where standard methods do not always work. This area is a particular research focus of Scott Sloan, Daichao Sheng and Andrew Abbo.