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4                                     Chapter 1  Introduction



                              solutions  only  for  simple  problems  as  taught  in  undergraduate
                              courses  where  differential  equations,  boundary  conditions  and
                              geometries are not complicated.  Most problems are limited to one
                              dimensional  problems  so  that  their  governing  equations  can  be
                              simplified from partial to ordinary differential equations.

                                         (b)  Numerical Method.    If  the  differential  equations,
                              boundary  conditions  and  geometry  of  a  given  problem  are
                              complicated,  solving  with  analytical  method  is  not  feasible.    We
                              need  to  find  an  approximate  solution  from  a  numerical  method.
                              There  are  many  numerical  techniques  for  finding  solutions  to
                              complex  problems.    The  popular  techniques  widely  used  are  the
                              finite element and finite volume methods.  This is mainly because
                              both  techniques  can  handle  problems  with  complex  geometry
                              effectively.

                                         Both  the  finite  element  and  finite  volume  methods
                              transform  the  governing  differential  equations  into  algebraic
                              equations.  In the process, many numerical techniques are needed.
                              The techniques include solving a large set of algebraic equations,
                              understanding concepts of the interpolation functions, determining
                              derivatives and integrations of functions numerically, etc.  Details
                              of these techniques are taught in undergraduate numerical method
                              courses and can be found in many introductory numerical method
                              textbooks.


                              1.2   Finite Element Method

                                         Because  most  of  CAE  commercial  software  packages
                              employ  the  finite  element  method  to  solve  for  solutions,  we  will
                              introduce the method in this section.

                                  1.2.1  What is the Finite Element Method?
                                         The finite element method is a numerical technique for
                              finding  approximated  solutions  of  problems  in  science  and
                              engineering.    These  problems  are  governed  by  the  three
                              components  including  differential  equations,  boundary  conditions
                              and geometries.
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