ABSTRACT
In order to determine the error in numerical solutions of complicated problems without knowing the exact solution or performing so-called duality in FEM analysis [1-3], it is practical to use two numerical models: one gives a lower bound and the other gives an upper bound of the unknown exact solution. This chapter discusses an S-FEM model that can be used for such a purpose. For convenience in discussion, we focus on the socalled force-driven solid mechanics problems: boundary value problems with homogeneous Dirichlet (or essential, or displacement) boundary conditions. The extension to other types of problems will be discussed in the remark section.
