FINITE ELEMENT METHOD
To obtain the best results from ANSYS, or for that matter any Finite
Element program it is important to understand the basic concepts and
limitations of the Finite Element Method.
The Finite Element Method is a technique for approximating the
governing differential equations for a continuous system with a
set of algebraic equations relating a finite number of variables. These
methods are popular because they can be easily programmed. The FE
techniques were initially developed for structural problems but they
have been extended to numerous field problems.
The basic steps involved in any FE Analysis consist of the following.
PREPROCESSING
 Create and discretize the solution domain into finite elements.
This involves dividing up the domain into subdomains, called
'elements', and selecting points, called nodes, on the interelement
boundaries or in the interior of the elements.
  Assume a function to represent the behavior of the element. This
function is approximate and continuous and is called the "shape
function".
  Develop equations for an element.
  Assemble the elements to represent the complete problem.
  Apply boundary conditions, initial conditions, and the loading. 
SOLVING
 Solve a set of linear or nonlinear algebraic equations
simultaneously to obtain nodal results, such as displacement values,
or temperature values, depending on the type of problem. 
POSTPROCESSING
 This stage involves processing the nodal data to get other
information such as values of principal stresses, heat fluxes, etc.

