4. Using Continuum Elements

The continuum (solid) family of stress/displacement elements is the most comprehensive of the element libraries in ABAQUS. There are some differences in the solid element libraries available in ABAQUS/Standard and ABAQUS/Explicit.

ABAQUS/Standard solid element library

The ABAQUS/Standard solid element library includes first-order (linear) interpolation elements and second-order (quadratic) interpolation elements in two or three dimensions using either full or reduced integration. Triangles and quadrilaterals are available in two dimensions; and tetrahedra, triangular wedges, and hexahedra (“bricks”) are provided in three dimensions. Modified second-order triangular and tetrahedral elements are also provided.

In addition, hybrid and incompatible mode elements are available in ABAQUS/Standard.

ABAQUS/Explicit solid element library

The ABAQUS/Explicit solid element library includes reduced-integration first-order (linear) interpolation elements in two or three dimensions. Modified second-order interpolation triangles and tetrahedra are also available. Full integration or regular second-order elements are not available in ABAQUS/Explicit.

For detailed information on the options available for continuum elements, please see Solid (continuum) elements, Section 22.1.1 of the ABAQUS Analysis User's Manual.

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.