Element records

These records describe the individual elements.

Record syntax

ElementType num (in) nodes (ia) crossSect (in) [mat (in)] [bodyLoads (ia)] [boundaryLoads (ia)] [activityltf (in)] [lcs (ra)] [nip (in)] <[remote]> <[partitions (ia)]>

The order of the records is arbitrary and the element number is given by num. Numbering may be non-contiguous: think of the number as a label assigned to an individual element, by which it is referenced.

Note

The element types themselves, and the parameters specific to each, are documented in the separate Element Library Manual. This section covers only the attributes common to all elements.

Parameters

nodes (ia)

The dof managers — nodes, sides and so on — defining the element geometry.

crossSect (in)

Number of the cross section record for the element. Required — but it need not be given in the element record itself: a cross section record that names a set assigns itself to every element of that set, which is the usual style in current input files. If the element ends up with no cross section from either source, the analysis stops.

[mat (in)]

Number of the material record for the element. Usually supplied by the cross section instead (see Cross section records), so it is optional here.

[nip (in)]

Number of integration points. The permitted values, and the default, depend on the element type. Note that adaptive error estimation often needs a higher integration order than the default; see Error estimators and indicators.

[lcs (ra)]

Orientation of the local coordinate system. The array holds six numbers: the first three are a direction vector of the local x-axis, the next three a direction vector of the local y-axis, and the local z-axis follows from the vector product. This is particularly useful for orthotropic materials that follow the element orientation. On a beam or truss element lcs has no effect, and the 1D element orientation is aligned with the global \(xx\) component.

Loads

[bodyLoads (ia)]

Body loads acting on the element volume, given as load record numbers. The records must be of a body load type, or an error is raised.

[boundaryLoads (ia)]

Boundary loads acting on the element boundary. The array has the layout

\[2\cdot size \; lnum(1)~id(1)~\dots~lnum(size)~id(size),\]

where \(size\) is the total number of loads applied to the element, \(lnum(i)\) is the applied load number, and \(id(i)\) the corresponding entity number to which the load is applied, for example a side or surface number. The entity numbering is element dependent and is described in the Element Library Manual. The records must be of a boundary load type, or an error is raised.

Element activity

[activityltf (in)]

Number of a time function controlling whether the element is active. A nonzero value of the function means the element is active — the default — and zero means it is inactive at that solution step.

This supports the insertion and removal of elements during the analysis, and is tested for structural and transport elements. It makes it possible to model, for instance, the temperature evolution of layered casting of concrete, where certain layers must be inactive before they are cast. See the OOFEM tests for an example of a hydrating material model, boundary conditions and element activity acting together.

Parallel mode

Note

This section applies only to the parallel build. See The parallel model for the overall picture.

[remote]

Forces the element to be a remote element. A remote element does not contribute to the governing equations of the local partition. Remote elements exist to implement the band of elements involved in the computation of nonlocal variables — see Fig. 3, which illustrates the approach for node-cut partitioning. Their role is to provide a local mirror of the integration point values of the corresponding element on the remote partition, which then undergo nonlocal averaging on the local partition. When this flag is not used, the element is assumed to be a local partition element.

[partitions (ia)]

When remote is used, this should contain the number of the remote partition on which the corresponding element is local; the array then has size one.

The parallel version also requires a unique global numbering of the elements across all partitions; see The parallel model.