The continuum family of stress/displacement elements is the most comprehensive of the element libraries in ABAQUS. For three-dimensional elements you have a choice of hexahedrons, tetrahedrons, and wedges; for two-dimensional elements the choice is between triangles and quadrilaterals. There are linear and quadratic versions for each of these basic element shapes. You have the choice between full- and reduced-integration elements for hexahedrons and quadrilaterals. Finally, you have the option of using either the standard or hybrid element formulation; for linear hexahedral or quadrilateral elements you have the additional possibility of using an incompatible mode formulation, while for quadratic triangular or tetrahedral elements you have the additional possibility of using a “modified” formulation.

When the permutations of all these various element options are made, the total number of solid elements available to you is large—over 20 just for three-dimensional models. The accuracy of your simulation will depend strongly on the type of element you use in your model. The thought of choosing which of these elements is best for your model may seem daunting, especially at first. However, you will come to view this selection as a 20+ piece tool set that provides you with the ability to choose just the right tool, or element, for a particular job.

This chapter discusses the effect that different element formulations and levels of integration have on the accuracy of a particular analysis. Some general guidelines for selecting continuum elements are also given. These provide the foundation upon which you can build your knowledge as you gain more experience using ABAQUS. The example at the end of this section will allow you to put this knowledge to use as you build and analyze a connecting lug.