the variational functional, and this method allows for the development of crack singular or perforated elements through the use of localized solution functions as the trial functions. Applications Since its mainstream introduction some 30 years ago, this modified finite element method has become increasingly popular to applications such as elasticity, Kirchhoff plates, thick plates, general three-dimensional solid mechanics, antisymmetric solid mechanics, potential problems, shells, elastodynamic problems, geometrically nonlinear plate bending, and transient heat conduction analysis among various others. It is currently being applied to steady, non-turbulent, incompressible, Newtonian fluid flow applications through ongoing research at the Faculty of Engineering and Information Technology (FEIT) at the Australian National University (ANU) in Canberra, Australia. The hybrid Trefftz method is also being applied to some fields, e.g. computational modeling of hydrated soft tissues or water-saturated porous media, through ongoing research project at the Technical University of Lisbon, Instituto Superior Técnico in Portugal. Notes References External links Hybrid-Trefftz research project at Instituto Superior Técnico in Lisbon, Portugal Numerical differential equations