Useful Tips in Finite Element Modeling and Analysis

Useful Tips

• Perhaps the simplest and most important rule in FEA modeling, in my opinion, is "KYMS"-Keep Your Models Simple. Most research and commercial FEA or BEA packages provide potential users with numerous features that actually are tempting to use even in basic problems. However, the first FEA/BEA model in any typical analysis/design cycle should be simple enough to be verified by inspection and some hand calculations.

  It is only after that the user gains some level of confidence in the simple model that he/she need to introduce additional levels of complexity and completness.

• For large problems, consider using "substructuring". Substructuring is a process of breaking up large FE models into components. These components have their own defined boundary conditions and loading. Of course, there is intercation between these components and it is captured in the subsequent assembly and solution phases.

• For large dynamic problmems, consider using "static condensation" or "Guyan Reduction" by identifying as few important dynamic degrees of freedom (called master dofs) as possible. The elimination of 'slave' degrees of freedom through Guyan reduction often results in a smaller size of problem to be solved.

• Whenever possible transient dynamic analysis should be preceded with a simple static analysis or an eigensolution. Static defelctions and fundamental modes give easy and straightforward information on the behavior of the FE model.

• Do not be tricked by Von Mises stress contours. These contours are often pretty; but hide stress irregularities and inconsistencies because they are weighted averages of teh different stress components.

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