the PDE can be developed for each of these elements. The total solution is then generated by
linking together, or “assembling,” the individual solutions taking care to ensure continuity
at the interelement boundaries. Thus, the PDE is satisfied in a piecewise fashion.
As in Fig. 31.1c, the use of elements, rather than a rectangular grid, provides a much
better approximation for irregularly shaped systems. Further, values of the unknown can be
generated continuously across the entire solution domain rather than at isolated points.
Because a comprehensive description is beyond the scope of this book, this chapter
provides a general introduction to the finite-element method. Our primary objective is to
make you comfortable with the approach and cognizant of its capabilities. In this spirit, the
following section is devoted to a general overview of the steps involved in a typical finiteelement
solution of a problem. This is followed by a simple example: a steady-state, onedimensional
heated rod. Although this example does not involve PDEs, it allows us to
develop and demonstrate major aspects of the finite-element approach unencumbered by
complicating factors. We can then discuss some issues involved in employing the finiteelement
method for PDEs.