2D loads on load panels

A load panel is a 2D element that does not have any stiffness but allows any loads applied on it to be distributed to surrounding 1D elements. A load panel is not structural and so does not contribute to the stiffness or mass of the structure. The purpose of the load panel is to allow loads to be defined as a face load then distributed to the beam elements surrounding the 2D element. In many ways face loads on load panels give an alternative to grid loads. See load panel vs. grid loads explanation for more information.

A load panel element must be surrounded by 1D elements on all sides. If the structure does not have a beam along a particular edge, then a 1D element is still required in this location but its property should be set to Dummy.

Note: the topology of load panel elements can be defined by only its corner nodes (i.e. the highlighted pink nodes in the image below)

The loads applied to load panels are distributed by searching for beam/bar elements that bound the panel and attributing loads to these elements based on the support condition. Bounding beam/bar elements that are dummy elements cannot take loads so an appropriate support condition should be selected to ensure loads are not attributed to them.

For elements with rigid offsets the basic load distribution is modified to avoid loads on the rigid offsets, while still maintaining the total load by applying a point load onto the end of the element.

Properties for a load panel element are defined in the 2D properties wizard or table. The 2D property contains the definition of the load distribution type: two-way, one-way and legacy as described in more detail below.

Two-way

Two-way load panel elements distribute load to the nearest edge.

One-way

One-way load panel elements distribute load to the nearest edge in the direction of its local x axis. To change the span direction, change the load panel element's orientation angle and/or the 2D property's axis system.

Legacy

Legacy load panel properties can only be used for load panel elements that are defined by either 3 or 4 nodes. Both a support pattern and the reference edge are required.

The support pattern defines the number of edges to which the load is transferred and the reference edge sets the selection of the free/loaded edges.

• All edges supported - the load is distributed to the edges in proportion to the contributing areas.

• Three edges supported - the load is distributed to the supporting edges so that as far a possible equilibrium is maintained. The edge opposite the reference edge does not take any load

• Two edges supported - the load spans from the sides adjacent to the reference edge.

• Two adjacent edges supported - the load is taken on the reference edge and the “next” edge on the element.

• One edge supported - the load is all attributed to the reference edge. The moment due to the offset of the load is ignored.

• Cantilever support - the forces are distributed as for one edge supported but the moment is applied to the edge so that equilibrium is achieved.

Viewing load panel elements

Setting the ‘Load panels’ labelling option in the Labels and Display Methods: On Elements dialog tab displays the load distribution pattern on load panels.