ABSTRACT
This chapter discusses problems whose geometry can be idealized as the one-dimensional line. When a line is discretized the one-dimensional line elements are obtained. However, this simplification is not possible for many problems. In some cases the problem must be solved in two dimensions such as the plate, torsion, and two-dimensional field problems. The situation becomes more complicated when all the three dimensions of the problem geometry need consideration. For finite element analysis of two-dimensional or three-dimensional cases, the problem must be discretized into a number of elemental areas or volumes, respectively, giving rise to two-dimensional or three-dimensional finite elements. Based on the shape of the element the two-dimensional elements can be classified mainly under two categories — triangular elements and quadrilateral elements. As in the triangular element case, it is advantageous to use the concept of local coordinate system for finite element formulations using quadrilateral finite elements.
