In FEA, what considerations go into choosing element size?

Question

What will be an ideal response?

Answer 1

The key to successful numerical solution of engineering field problems is the division of the solid volume into small, finite-sized elements. The process of subdividing the solid into elements is referred to as meshing. In general, the smaller the elements, the more accurate the solution; however, if the elements are too small, you may introduce error into your model due to computational approximations. Further, smaller element sizes mean more elements and computation time will significantly increase. Element sizes should be reduced wherever there is curvature in the model to compute desired quantities accurately in those regions. In general, you can use larger elements in areas where stresses are relatively static and you need small elements in areas where the stresses are rapidly changing. Knowing what sizes to use for elements will take practice.


Fortunately, most of the tedium in meshing has been eliminated or greatly reduced with modern FEA software applications. In most cases, you merely specify a nominal element size and the software will automatically create the elements for you; the software also will automatically reduce the element sizes when it encounters curved regions. As you gain experience with the finite element method, you will get a better feel for reasonable nominal element sizes; but for now, you should rely on your instructor to provide insight into the modeling procedure.