> For the complete documentation index, see [llms.txt](https://gitbook.saf.guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook.saf.guide/loads/structuralsurfaceactionthermal.md).

# StructuralSurfaceActionThermal

## Thermal load on surface elements

The thermal load on the surface elements ([StructuralSurfaceMember](/structural-analysis-elements/structuralsurfacemember.md#2d-member-plate-wall)). The variation of the thermal load can be constant or linear over the cross-section of the beam.

### Specification in the excel

| Name of the column header | Type of data |   Value example or enum definition   | Required value             | Description                                                                                                                                                                                                                                                                                                                                                                                                                            |
| ------------------------- | ------------ | :----------------------------------: | -------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Name                      | String       |                  LT1                 | yes                        | Human readable unique name of the load                                                                                                                                                                                                                                                                                                                                                                                                 |
| Variation                 | Enum         |     <p>Constant</p><p>Linear</p>     | yes                        | <p>Specifies how the temperature varies</p><p>Constant: The load is defined by means of a single value T1. The value specifies the change in temperature of the 2D member (straight ΔT). Temperature change is constant along the cross-section.</p><p>Linear: The load is defined by means of a set of two values T1 and T2. The individual values specify the temperature at individual surfaces - top, bottom of the 2D member.</p> |
| TempT \[°C]               | Double       |                  18                  | <p>yes<br></p>             | <p>Specifies the first size of the load in Celsius/Fahrenheit.</p><p>For constant: Delta temperature on the center plane</p><p>For linear: Temperature of top surface (LCS direction +z) of 2D member</p>                                                                                                                                                                                                                              |
| TempB \[°C]               | Double       |                  18                  | yes, if Variation = Linear | <p>Specifies the second size of the load in Celsius/Fahrenheit.</p><p>For linear: Temperature of bottom surface (LCS direction -z) of 2D member</p>                                                                                                                                                                                                                                                                                    |
| 2D Member                 | String       |                  S15                 | yes                        | The name of the [StructuralSurfaceMember](/structural-analysis-elements/structuralcurvemember.md#1d-member-beam-column) or [StructuralSurfaceActionDistribution](/loads/structuralsurfaceactionthermal.md)which is the surface load related to.                                                                                                                                                                                        |
| 2D Member Region          | String       |                  R1                  | yes, if on region          | The name of the [StructuralSurfaceMemberRegion](/structural-analysis-elements/structuralsurfacememberregion.md#region-of-different-plate-thickness) to which is the surface action related if it is available on 2D member.                                                                                                                                                                                                            |
| Load case                 | String       |                  LC1                 | yes                        | The name of the load case to which the load belongs                                                                                                                                                                                                                                                                                                                                                                                    |
| Parent ID                 | String       | 67b35d84-3d04-47aa-aa4a-dc1263982320 | no                         | <p>Is filled for objects created be dividing curved geometry to series of straight line objects.<br><br>Parent ID will ensure that curved edge is imported as straight parts to nonsupporting application, and back to original supporting application as curved geometry.</p><p>To ensure successful round trip of segmented objects and their related objects, Parent ID needs to be present in both directions.</p>                 |
| Id                        | String       | 39f238a5-01d0-45cf-a2eb-958170fd4f39 | no                         | Unique attribute designation                                                                                                                                                                                                                                                                                                                                                                                                           |