ABAQUS Verification Manual  


1.6.17 Automatic surface definition and surface trimming

Product: ABAQUS/Standard  

Elements tested

C3D4    C3D8    CPS3    CPS4   

Problem description

The input files ele_trim2d.inp and ele_trim3d.inp verify the automatic surface generation capability and trimming of surfaces. When a surface is defined without specifying the face identifiers of elements, the faces in the element set that are on the exterior (free) surface of the model form the surface. This definition may result in the inclusion of unwanted faces. Surface trimming provides the user with some basic control over the extent of open surfaces created on solid element meshes.

The input file ele_trimdef.inp tests the default trimming option. ABAQUS will, by default, trim all contact surfaces except master surfaces involved in a finite-sliding contact pair.

Results and discussion

Some of the examples from the tests are shown below. They illustrate the recursive elimination of the ends of two-dimensional surfaces and the edges of three-dimensional surfaces. Trimming has no effect on closed surfaces (ones with no ends or edges). In each example the shaded elements in the model are used as the element set in the surface definition. The automatic surface generated and the surface generated by trimming are shown separately.

Trimming of two-dimensional surfaces

Figure 1.6.17–1 and Figure 1.6.17–2 show how trimming of surfaces works for two-dimensional quadrilateral elements. Any face that includes an end node and a corner node is removed during trimming. Figure 1.6.17–3 and Figure 1.6.17–4 show trimming of surfaces for two-dimensional triangular elements.

Trimming of three-dimensional surfaces

Figure 1.6.17–5 and Figure 1.6.17–6 show the trimming of surfaces for three-dimensional brick elements. Figure 1.6.17–7 and Figure 1.6.17–8 show how trimming of surfaces works for three-dimensional tetrahedron elements.

Default trimming of contact surfaces

The default trimming option was investigated for surfaces involved in small-sliding, finite-sliding, and both small- and finite-sliding contact pairs.

Input files

ele_trim2d.inp

Trimming of two-dimensional surfaces.

ele_trim3d.inp

Trimming of three-dimensional surfaces.

ele_trimdef.inp

Default trimming of contact surfaces.

Figures

Figure 1.6.17–1 Quadrilateral elements—Example 1.

Figure 1.6.17–2 Quadrilateral elements—Example 2.

Figure 1.6.17–3 Triangular elements—Example 1.

Figure 1.6.17–4 Triangular elements—Example 2.

Figure 1.6.17–5 Brick elements—Example 1.

Figure 1.6.17–6 Brick elements—Example 2.

Figure 1.6.17–7 Tetrahedron elements—Example 1.

Figure 1.6.17–8 Tetrahedron elements—Example 2.