2.2.4 Define Loads

Fig. 2.2.4.1: A cantilever with a point-load at its tip

In fig. 2.2.4.1 a point-load of 1 kilo Newton ($kN$) is added at the tip of the cantilever beam. A vector at the input-plug “Force” specifies direction and magnitude of the load: since the global Z-axis points upwards a load acting downwards has a negative z-component.

The input plug “LCase” can be used to set the name of the load case in which the load acts. This allows different load scenarios (e.g., wind from different directions) to be created and combined later on.

Fig. 2.2.4.2: Definitions of different load types

The dropdown lists at the bottom of the “Loads” component allows selection between different types of loads as shown in Figure 2.2.4.2:

• Gravity Loads: Act on the entire structure.

• Point Loads: Concentrated load; Location can be specified by node index or position.

• Initial Strain: Imposes an initial change of geometry on structural elements.

• Temperature: Via the coefficient of thermal expansion (see section 3.5.1) temperature changes are linked to axial or in-plane strains.

• Distributed Loads on Meshes: They get reduced to approximately statically equivalent node and beam loads. There exist two variants: "MeshLoad Const" which defines a uniform surface load and "MeshLoad Var" where pressures can be defined for each mesh-face individually.

The directions of gravity and point loads refer to the global coordinate system. The direction vector of beam and mesh loads can be specified relative to the global or local coordinate system (related to the element or mesh).

Point-loads can only be defined at structure nodes. If a Point-load position is not set on a node, the “Assemble Model” component will issue an error. The error message will contain the coordinates of the point load that does not attach to the model. To get an overview of the faulty model, deactivate the corresponding "Load" component and use the “ModelView” component to visually inspect the model.

Besides the above loads which apply irrespective of the type of loaded element, the component "Beam Loads" can be used to define loads specific to beams (see section 3.2.2).