This command is used to construct a zeroLength element object, which is defined by two nodes at the same location. The nodes are connected by multiple UniaxialMaterial objects to represent the force-deformation relationship for the element.
|element zeroLength $eleTag $iNode $jNode -mat $matTag1 $matTag2 ... -dir $dir1 $dir2 ...<-doRayleigh $rFlag> <-orient $x1 $x2 $x3 $yp1 $yp2 $yp3>|
|$eleTag||unique element object tag|
|$iNode $jNode||end nodes|
|$matTag1 $matTag2 ...||tags associated with previously-defined UniaxialMaterials|
|$dir1 $dir2 ...||material directions:|
|1,2,3 - translation along local x,y,z axes, respectively;|
|4,5,6 - rotation about local x,y,z axes, respectively|
|$x1 $x2 $x3||vector components in global coordinates defining local x-axis (optional)|
|$yp1 $yp2 $yp3||vector components in global coordinates defining vector yp which lies in the local x-y plane for the element. (optional)|
|$rFlag||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 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). EXAMPLE:
element zeroLength 1 2 4 -mat 5 6 -dir 1 2; # truss tag 1 between nodes 2 and 4 acting in directions 1 and 2 with materials 5 and 6 respectively.
element zeroLength 1 1 2 -mat 1 -dir 1 -orient 1 1 0 -1 1 0; # truss tag 1 between nodes 1 and 2 acting in local direction 1 defined with material 1. Local direction 1 attains 45 degrees with global X axis
element zeroLength 1 1 2 -mat 1 -dir 1 -doRayleigh 1 -orient 1 1 0 -1 1 0; # the same as the example above but also includes the stiffness of this element in calculation of the damping matrix if Rayleigh command is invoked later.
Code Developed by: Gregory L. Fenves, University of Texas, Austin.