6335x
000270
2024-02-07

Surface loads are forces, moments, masses, temperature effects, or imposed deformations that act on surfaces. Openings are omitted from the surface load.

In the list, select the 'Load Case' to which you want to assign the load.

### Categories

The following options are available in the 'Load type' list:

Force Uniformly distributed, linearly variable, or radially acting force on surface
Temperature Temperature load that is radially arranged or uniformly distributed, linearly variable over thickness of surface (positive load value: surface or surface top side heats up)
Axial Strain Imposed or compressive strain ε of surface (positive load value: surface is stretched)
Precamber Imposed curvature of surface
Rotary Motion Centrifugal force from mass and angular velocity ω on surface
Mass Mass continuously distributed over surface, which is relevant for Dynamic Analyses.
Ponding Rain load applied on multi-curved surfaces considering runoffs (ponding water)

The load type as well as the effect of the signs are illustrated in the upper dialog graphic.

Important

To consider a mass in the calculation, activate the Active mass option in the 'Static Analysis Settings' dialog box (see the image Basic Settings ).

The 'Load distribution' list provides various options for displaying the arrangement of the load.

The load distribution scheme is illustrated in the upper dialog graphic. In the 'Parameters' dialog section, you can then specify the values, the reference nodes, and other parameters of the load.

In the 'Coordinate system' list, define whether the load acts in the direction of the local xyz-surface axes or the global XYZ-axes. Alternatively, you can select a user-defined coordinate system or create a new one. The local z-axis is oriented perpendicular to the surface.

Info

For calculations according to the linear static analysis, it does not matter whether a load is defined as local or equivalent global. However, for geometrically nonlinear calculations, differences are possible: The global load keeps its direction when finite elements are twisting. In contrast, a locally defined load is twisting on the surface in accordance with the twist of the elements.

Select the 'Load direction' from the list to define the effect of the load. Depending on the coordinate system, the local surface axes x, y, z, the global axes X, Y, Z, or the user-defined axes U, V, W are available for selection.

The surface load can be related to the true area (such as a weight load) or the projected area (such as a snow load). The load direction is illustrated in the dialog sketch.

Info

Loads acting perpendicular to the surface such as wind or internal pressure are usually defined locally in the z-direction.

### Parameters

Specify the load value of the force, moment, or mass. For concentrated or variable loads, several input fields are available where you can describe the line load. The meaning of the respective parameters is illustrated in the load sketch.

Info

The reference nodes do not have to be in the surface. They can also lie outside.

For loads 'Varying in Z', a table is available to describe the Z-ordinates by the corresponding load values.

### Options

You can affect the display of the load vectors by the 'Display on opposite side' option.

Parent Chapter

Product Feature