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C H A P T E R 3
Where We Begin to Go Wrong
When all you have is a hammer, everything looks like a
nail.
Anonymous
Note To e Instructor
We have often told our students that one of the advantages of finite element analysis is that it is relatively
easy to perform. We also add that one of the disadvantages of finite element analysis is that it can be too easy
to perform. As ease of use becomes more prevalent, it can belie the complexity of the actual solution to one’s
problem. Clearly, a distinct advantage has always been to give drudgery and repetitive tasks to the machine
to free up time for the analyst to spend critically thinking. So the computer is a fast, but not necessarily
intelligent, aid in obtaining sufficiently accurate solutions. e requisite intelligence lives primarily in two
places:
1. commercial software’s pre-programmed algorithms that approximately model theories with which
students may or may not be familiar and
2. an analyst’s pre-processing of a model formulation and interfacing this model with the commercial
software.
Where students go wrong can often be traced to one of these two lapses in intelligence. e first
appears when students attempt problems whose solutions they do not know a priori. In such cases, the
theory they know may or may not be relevant or sufficient to model the problem. Students often view this as
carte blanche for initiating a finite element analysis. One common pitfall is that it is more difficult to validate
a solution you do not know or understand a priori. In such cases, new learners often turn to the theory
they know when attempting to validate simulation results. Comparing the results of correct finite element
analysis with expectations using inadequate theory is a common mistake made by students in introductory
courses. is is particularly true in courses where commercial software is used as part of the student laboratory
experience. We illustrate this first “way to go wrong” with three illustrative examples.
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