For the purposes of Finite Element Analysis (FEA), beam elements are those that transfer both force and moments. In Neara, beam elements are used to model both crossarms and poles. When completing FEA these beam elements are split into segments.
Structural analysis calculations are performed at the start and end of each segment and contribute to the final assessment of the whole crossarm or pole.
Crossarm segments
The number of segments for crossarms will depend on any changes along the axis of the beam which will occur when components are attached including insulators and braces and where it connects to the pole.
Pole segments
The number of segments for poles will depend on the following:
Changes along the axis of the beam including attachment of components such as crossarms or braces, shape changes (for sectioned poles or overlapping tubular steel poles), and at the ground line
The minimum number of pole segments (Min Pole Segments) defined in the FEA panel under the Structure Model section
Small segments
In cases where a beam segment would be smaller than 2.5 cm or ~1 inch the element will be discarded and beam elements from the left and right will be elongated such that they meet at the mid point of now discarded element. All other elements that were connected to now discarded nodes will be connected to a newly added midpoint node. This is done to prevent FEA solver instabilities caused by very short and unequal element sizes.
Simple example
Consider this simple wood pole with a two conductor termination assembly and a stay/guy wire. As part of this analysis the beam elements, crossarm and pole, will be split into multiple segments.
Perspective view of the pole model:
FEA model showing segmented view of the pole and attached components:
In the FEA model, beam elements are depicted with ochre color and segments are labelled with numbers of the same color.
In this example the crossarm is segmented at the attachment points of the insulators, brace, and pole. The pole is segmented at the attachment points of the crossarm and brace, then in equally spaced increments to the ground line to meet or exceed the Min Pole Segments defined in the FEA panel.
For more information about FEA, see