# 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 |

Constant

Linear

| yes |

Specifies how the temperature varies

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.

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.

| | TempT \[°C] | Double | 18 |

yes

|

Specifies the first size of the load in Celsius/Fahrenheit.

For constant: Delta temperature on the center plane

For linear: Temperature of top surface (LCS direction +z) of 2D member

| | TempB \[°C] | Double | 18 | yes, if Variation = Linear |

Specifies the second size of the load in Celsius/Fahrenheit.

For linear: Temperature of bottom surface (LCS direction -z) of 2D member

| | 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 |

Is filled for objects created be dividing curved geometry to series of straight line objects.

Parent ID will ensure that curved edge is imported as straight parts to nonsupporting application, and back to original supporting application as curved geometry.

To ensure successful round trip of segmented objects and their related objects, Parent ID needs to be present in both directions.

| | Id | String | 39f238a5-01d0-45cf-a2eb-958170fd4f39 | no | Unique attribute designation | --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://gitbook.saf.guide/loads/structuralsurfaceactionthermal.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.