Section Aggregator

This command is used to construct a SectionAggregator object which groups previously-defined UniaxialMaterial objects into a single section force-deformation model.

section Aggregator $secTag $matTag1 $string1 $matTag2 $string2 ....... <-section $sectionTag>


$secTag		unique section object integer tag
$matTag1, $matTag2 ...		previously-defined UniaxialMaterial objects
$string1, $string2 ....		the force-deformation quantities corresponding to each section object. One of the following strings is used:
	P		Axial force-deformation
	Mz		Moment-curvature about section local z-axis
	Vy		Shear force-deformation along section local y-axis
	My		Moment-curvature about section local y-axis
	Vz		Shear force-deformation along section local z-axis
	T		Torsion Force-Deformation
<-section $sectionTag>		specifies a previously-defined Section object (identified by the argument $sectionTag) to which these UniaxialMaterial objects may be added to recursively define a new Section object

NOTE: The UniaxialMaterial objects aggregated in this Section object are uncoupled from each other as well as from the Section object represented by $sectionTag, if present.

There are two main tasks that can be performed using the Section Aggregator:

1. Group previously defined uniaxial materials to describe stress resultant section behavior

Section Aggregator 1

EXAMPLE:

section Aggregator 1 2 Vy 5 Mz; #create new section with IDtag 1, taking the existing material tag 2 to represent the shear and the existing material tag 5 to represent the moment.

2. Add to an existing section

Section Aggregator 2

EXAMPLE:

section Aggregator 2 2 Vy -section 4; # create new section with IDtag 2, taking the existing material tag 2 to represent the shear and adding it to the existing section tag 4, which may be a fiber section where the interaction betweeen axial force and flexure is already considered.