The verification tests in this section consist of pairs of models. Within each pair the first, or ancestor, model undergoes a simple deformation to a deformed configuration. The second, or descendent, model represents the deformed configuration of the ancestor with a different mesh and possibly with different element types. The solution from the ancestor model is transferred to the descendent model, and the resulting state of this model is verified to be consistent with the ancestor in its deformed configuration.

The ancestor model has a simple rectangular geometry. In most cases the model contains two distinct material regions, shown in Figure 3.13.1–1. This model undergoes a uniform compression, as shown in Figure 3.13.1–2, and the resulting configuration is chosen as the geometry for the descendent model, as shown in Figure 3.13.1–3. Models with axisymmetric elements are placed at a large radial position so that the element behavior is near to that of plane strain elements. Models with three-dimensional elements have a depth of 10 units and have meshes slightly different from those shown in the following planar mesh figures.

Mesh:

Nonuniform meshes are chosen, as illustrated in Figure 3.13.1–4, Figure 3.13.1–5, Figure 3.13.1–6, and Figure 3.13.1–7.

Material properties are selected from among the following models. In cases where two different material properties are used in adjacent regions, the parameters listed first are applied to one material region and the parameters listed second are applied to the other:

Elastic (including UMAT implementation)

Elastic/plastic

Hyperelastic

Boundary conditions:

The ancestor model is constrained from vertical motion on the bottom surface and from horizontal motion along the interface between the material regions. The top surface is then compressed with a uniform motion while the sides expand with a prescribed, volume preserving motion. These boundary conditions result in a deformed configuration that is independent of the material models used in the analysis. In some tests the deformed configuration shown in Figure 3.13.1–2 is reached at an intermediate step and increment, which enables testing of solution mapping from intermediate configurations.

Ancestor models with temperature degrees of freedom have a temperature of zero prescribed on the lower boundary and a temperature of 1000 prescribed on the upper boundary, resulting in a linear variation in temperature across the height of the model.