ZeroLength Section Element

This command is used to construct a zero length element object, which is defined by two nodes at the same location. The nodes are connected by a single section object to represent the force-deformation relationship for the element.

element zeroLengthSection $eleTag $iNode $jNode $secTag <-orient $x1 $x2 $x3 $yp1 $yp2 $yp3> <-doRayleigh $rFlag>






unique element object tag


list integer

2 end nodes



tag associated with previously-defined Section object


list float

(optional) 3 components in global coordinates defining local x-axis


list float

(optional) 3 components in global coordinates defining vector yp
which lies in the local x-y plane for the element.



optional, default = 0
rFlag = 0 NO RAYLEIGH DAMPING (default)
rFlag = 1 include rayleigh damping


If the optional orientation vectors are not specified, the local element axes coincide with the global axes. Otherwise the local z-axis is defined by the cross product between the vectors x and yp vectors specified on the command line.

The section force-deformation response represented by section string P acts along the element local x-axis, and the response for code Vy along the local y-axis. The other modes of section response follow from this orientation.

The valid queries to a zero-length element when creating an ElementRecorder object are ‘force,’ ‘deformation,’ ‘stiff,’ and ‘section $secArg1 secArg2 …’.


If the distance between end noes is not 0.0 a warning message will appear when the script is run. This is just a warning in case you have made a mistake as most users when they use zeroLength elements are wanting to use them in the more normal way. ZeroLength elements can be used between nodes with non-zero length.


The following examples demonstrate the commands in a script to add three zeroLength elements to domain. The three to be added have element tags 1, 2, and 3. Element 1 has nodes 2 and 3 as its end ndes, has two materials 5 and 6 acting in directions 1 and 2. Element 2 has as its end nodes 4 and 5, has only one material 1 acting in direction 1, the element has a global orientation.

  1. Tcl Code

element zeroLengthSection 1 2 4 6
element zeroLengthSection 2 4 5 6 -orient 1 1 0 -1 1 0
element zeroLengthSection 2 4 5 6 -orient 1 1 0 -1 1 0 -doRayleigh 1

Code Developed by: Michael H. Scott