3-D Conduction
Bar
LINK33 Element Description
LINK33 is a uniaxial element with the ability to conduct heat between its nodes. The element has a single degree of freedom, temperature, at each node point. The conducting bar is applicable to a steady-state or transient thermal analysis.
If the model containing the conducting bar element is also to be analyzed structurally, the bar element should be replaced by an equivalent structural element. See LINK33 in the Mechanical APDL Theory Reference for more details about this element.
LINK33 Input Data
The geometry, node locations, and the coordinate system for this conducting bar are shown in Figure 33.1: LINK33 Geometry. The element is defined by two nodes, a cross-sectional area, and the material properties. Specific heat and density are ignored for steady-state solutions. The thermal conductivity is in the element longitudinal direction.
Element loads are described in Nodal Loading. Heat generation rates may be input as element body loads at the nodes. The node J heat generation rate HG(J) defaults to the node I heat generation rate HG(I).
A summary of the element input is given in "LINK33 Input Summary". A general description of element input is given in Element Input.
LINK33 Input Summary
- Nodes
I, J
- Degrees of Freedom
TEMP
- Real Constants
AREA - Cross-sectional area
- Material Properties
MP command: KXX, DENS, C, ENTH
- Surface Loads
None
- Body Loads
- Heat Generation --
HG(I), HG(J)
- Special Features
- KEYOPTS
None
LINK33 Output Data
The solution output associated with the element is in two forms:
Nodal temperatures included in the overall nodal solution
Additional element output as shown in Table 33.1: LINK33 Element Output Definitions
The heat flow rate is in units of Heat/Time and is positive from node I to node J. 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 33.1: LINK33 Element Output Definitions
| Name | Definition | O | R |
|---|---|---|---|
| EL | Element Number | Y | Y |
| NODES | Nodes - I, J | Y | Y |
| MAT | Material number | Y | Y |
| VOLU: | Volume | Y | Y |
| XC, YC, ZC | Location where results are reported | Y | 1 |
| LENGTH | Length | Y | Y |
| AREA | Input area | Y | Y |
| TEMP(I, J) | Temperatures - I, J | Y | Y |
| HEAT RATE | Heat flow rate from node I to node J | Y | Y |
| THERMAL FLUX | Thermal flux (heat flow rate/cross-sectional area) | Y | Y |
Available only at centroid as a *GET item.
Table 33.2: LINK33 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 33.2: LINK33 Item and Sequence Numbers:
- Name
output quantity as defined in the Table 33.1: LINK33 Element Output Definitions
- Item
predetermined Item label for ETABLE command
- E
sequence number for single-valued or constant element data
LINK33 Assumptions and Restrictions
Heat is assumed to flow only in the longitudinal element direction.
The element must not have a zero length, so nodes I and J must not be coincident.
A free end of the element (i.e., not adjacent to another element and not subjected to a boundary constraint) is assumed to be adiabatic.
LINK33 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.
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