The finite element method is the representation of a body or a structure by an assemblage of sub-divisions called as finite elements. These elements are interconnected at joints which are called nodes or nodal points. Simple functions are chosen to approximate the distribution of actual displacements over each finite element. Such assumed functions are called displacement functions or displacement models. The unknown magnitude of the displacement functions are the displacements at the nodal points. Hence the final solutions will yield the approximate displacements at discrete locations in the body at the nodal points. A displacement model can be expressed in various forms, such as polynomials and trigonometric functions.