ZeroLength Element

This command is used to construct a zeroLength element object, which is defined by two nodes at the same location. A zeroLength element is similar to a set of springs placed between two nodes, each spring providing the force displacement relationship for a specified degree-of-freedom. The nodes are connected by multiple UniaxialMaterial objects, which provide the force-deformation relationship for the element in that degree-of-freedom direction.

element zeroLength $eleTag $iNode $jNode -mat $matTag -dir $dir
                   <-doRayleigh $rFlag> <-orient $x $yp>
Argument Type Description
$eleTag [in teger]{.t itle-ref} unique element object tag

$endNodes		 2 end nodes
$matTags list of n material tags
$dirIDs
list of n degree-of-freedom directions
1,2,3 - translation along local x,y,z axes,
4,5,6 - rotation about local x,y,z axes
$x (optional) 3 components in global coordinates defining local x-axis
$yp
(optional) 3 components in global coordinates defining vector yp
which lies in the local x-y plane for the element.
$rFlag [in teger]{.t itle-ref}
optional, default = 0
rFlag = 0 NO RAYLEIGH DAMPING (default)
rFlag = 1 include rayleigh damping

Note

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 valid queries to a zero-length element when creating an ElementRecorder object are 'force,' 'deformation,' and 'material $i matArg1 matArg2 ...' Where $i is an integer indicating which of the materials whose data is to be output (a 1 corresponds to $matTag1, a 2 to $matTag2, and so on).

Warning

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 zeroLength 1 2 4 -mat 5 6 -dir 1 2
element zeroLength 2 4 5 -mat 1 -dir 1 -orient 1 1 0 -1 1 0
element zeroLength 3 5 6 -mat 1 -dir 1 -doRayleigh 1
  1. Python Code
element('zeroLength',1,2,4,'-mat',5,6,'-dir',1,2)
element('zeroLength',2,4,5,'-mat',1,'-dir',1,'-orient',1,1,0,-1,1,0)
element('zeroLength',3,5,6,'-mat',1,'-dir',1,'-doRayleigh',1)

Code Developed by:

Back to top