3.1.9.2. 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>
Argument |
Type |
Description |
|---|---|---|
$eleTag |
integer |
unique element object tag |
$endNodes |
list integer |
2 end nodes |
$secTag |
integer |
tag associated with previously-defined Section object |
$x |
list float |
(optional) 3 components in global coordinates defining local x-axis |
$yp |
list float |
(optional) 3 components in global coordinates defining vector yp
which lies in the local x-y plane for the element.
|
$rFlag |
integer |
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 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 …’.
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.
Example
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.
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