3-D Infinite
Solid
INFIN111 Element Description
INFIN111 models an open boundary of a 3-D unbounded field problem. A single layer of elements is used to represent an exterior sub-domain of semi-infinite extent. The layer models the effect of far-field decay in magnetic, electrostatic, thermal, or electric current conduction analyses. For information about enclosed elements and analysis types, see Table 111.1: INFIN111 Analyses. See INFIN111 in the Mechanical APDL Theory Reference for more details about this element.
INFIN111 Input Data
The geometry, node locations, and the coordinate system for the element are shown in Figure 111.1: INFIN111 Geometry. KEYOPT(1) specifies the degree(s) of freedom to be used. KEYOPT(2) specifies whether a 8-node or 20-node element is used.
Only one layer of INFIN111 elements should be used between the finite element model and the exterior (infinite) surface. The nodes may be input starting at any corner node, but the face opposite of the finite element model (the exterior face) must be flagged as an infinite surface. This is usually done by selecting the nodes at the outer surface and issuing the SF,all,INF command. The other faces have no meaning. For best results, edges connecting the inner and outer surfaces of the infinite element should be radial from the center of the model.
A summary of the element input is given in "INFIN111 Input Summary". A general description of element input is given in Element Input.
INFIN111 Input Summary
- Nodes
I, J, K, L, M, N, O, P (if KEYOPT(2) = 0) I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, A, B (if KEYOPT(2) = 1) - Degrees of Freedom
Set by KEYOPT(1). See Table 111.1: INFIN111 Analyses.
- Real Constants
None
- Material Properties
- Surface Loads
- Infinite Surface Flags --
face 1 (J-I-L-K), face 2 (I-J-N-M), face 3 (J-K-O-N), face 4 (K-L-P-O), face 5 (L-I-M-P), face 6 (M-N-O-P)
- Body Loads
None
- Special Features
None
- KEYOPT(1)
Element degree of freedom. See Table 111.1: INFIN111 Analyses.
- KEYOPT(2)
Element definition:
- 0 --
8-node brick
- 1 --
20-node brick
- KEYOPT(6)
Electric charge reaction sign:
- 0 --
Negative
- 1 --
Positive
Analysis categories are shown in the following table. KEYOPT(1) specifies the element degree of freedom.
Table 111.1: INFIN111 Analyses
| Analysis Category | KEYOPT(1) | DOF Label | Reaction Solution | Enclosed Elements | Analysis Type |
|---|---|---|---|---|---|
| Magnetic | 0 | MAG | Magnetic Flux (F label = FLUX) | Static | |
| Electrostatic | 2 | VOLT | Electric Charge (F label = CHRG) | Static Harmonic | |
| Thermal | 3 | TEMP | Heat Flow (F label = HEAT) | Steady-state Transient | |
| Electric Current Conduction | 4 | VOLT | Electric Current (F label = AMPS) | Steady-state Harmonic Transient |
INFIN111 material properties are shown in the following table. Nonzero material properties must be defined. Material properties are defined with the MP, MPDATA and EMUNIT commands.
Table 111.2: INFIN111 Material Properties
| Analysis Category | KEYOPT(1) | Material Properties |
|---|---|---|
| Magnetic | 0 | MUZERO |
| Electrostatic | 2 | PERX, PERY, PERZ, LSST, RSVX, RSVY, RSVZ |
| Thermal | 3 | KXX, KYY, KZZ, DENS, C |
| Electric Current Conduction | 4 | RSVX, RSVY, RSVZ, LSST, PERX, PERY, PERZ |
INFIN111 Output Data
The solution output associated with the element is in two forms:
Nodal potentials included in the overall nodal solution
Additional element output as shown in Table 111.3: INFIN111 Element Output Definitions
The element output directions are parallel to the element coordinate system. A general description of solution output is given in Solution Output. See the Basic Analysis Guide for ways to view results.
The Element Output Definitions table uses the following notation:
A colon (:) in the Name column indicates that the item can be accessed by the Component Name method (ETABLE, ESOL). The O column indicates the availability of the items in the file Jobname.OUT. The R column indicates the availability of the items in the results file.
In either the O or R columns, “Y” indicates that the item is always available, a number refers to a table footnote that describes when the item is conditionally available, and “-” indicates that the item is not available.
Table 111.3: INFIN111 Element Output Definitions
| Name | Definition | O | R |
|---|---|---|---|
| EL | Element Number | Y | Y |
| NODES | Nodes - I, J, K, L, M, N, O, P (if KEYOPT(2) = 0); Nodes - I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, A, B (if KEYOPT(2) = 1) | Y | Y |
| MAT | Material number | Y | Y |
| VOLU: | Volume | Y | Y |
| XC, YC, ZC | Location where results are reported | Y | 4 |
| MUZERO | Magnetic permeability of free space | 1 | 1 |
| PERX, PERY, PERZ | Electric relative permittivity | 2 | 2 |
| KXX, KYY, KZZ | Thermal conductivity | 3 | 3 |
Available only at centroid as a *GET item.
Table 111.4: INFIN111 Item and Sequence Numbers lists output available through the ETABLE command using the Sequence Number method. See The General Postprocessor (POST1) in the Basic Analysis Guide and The Item and Sequence Number Table in this reference for more information. The following notation is used in Table 111.4: INFIN111 Item and Sequence Numbers:
- Name
output quantity as defined in the Table 111.3: INFIN111 Element Output Definitions
- Item
predetermined Item label for ETABLE command
- E
sequence number for single-valued or constant element data
INFIN111 Assumptions and Restrictions
Assumptions and restrictions listed for INFIN110 elements also apply to INFIN111 elements (see INFIN110 Assumptions and Restrictions).
There are considerations in the application of INFIN111 that will lead to optimal performance in the analysis of your model. These consideration are covered in detail in the Low-Frequency Electromagnetic Analysis Guide.
When used in a model with the higher-order elements SOLID87, SOLID90, SOLID98, SOLID122, SOLID123, SOLID231, and SOLID232, use the higher-order setting for INFIN111 (KEYOPT(2) = 1).
This element may not be compatible with other elements with the VOLT degree of freedom. To be compatible, elements must have the same reaction solution for the VOLT DOF. Elements that have an electric charge reaction solution must all have the same electric charge reaction sign. KEYOPT(6) sets the electric charge reaction sign. For more information, see Element Compatibility in the Low-Frequency Electromagnetic Analysis Guide.
INFIN111 Product Restrictions
When used in the product(s) listed below, the stated product-specific restrictions apply to this element in addition to the general assumptions and restrictions given in the previous section.
ANSYS Mechanical Pro
The MAG, AZ, and VOLT degrees of freedom are not active. KEYOPT(1) defaults to 3 (TEMP) instead of 0 and cannot be changed.
ANSYS Mechanical Premium
The MAG, AZ, and VOLT degrees of freedom are not active. KEYOPT(1) defaults to 3 (TEMP) instead of 0 and cannot be changed.