Corotational Transformation

This command is used to construct the Corotational Coordinate Transformation (CorotCrdTransf) object, which performs an exact geometric transformation of beam stiffness and resisting force from the basic system to the global coordinate system.

For a two-dimensional problem:

geomTransf Corotational $transfTag <-jntOffset $dXi $dYi $dXj $dYj>

For a three-dimensional problem:

geomTransf Corotational $transfTag $vecxzX $vecxzY $vecxzZ <-jntOffset $dXi $dYi $dZi $dXj $dYj $dZj>

NOTE: The Corotational transformation is only available with the Win32 version of OpenSees.

The element coordinate system and joint offset values are specified as in the Linear transformation.

$transfTag	unique identifier for CrdTransf object
$vecxzX $vecxzY $vecxzZ	X, Y, and Z components of vecxz, the vector used to define the local x-z plane of the local-coordinate system. (These items need to be specified for the three-dimensional problem.) These components are specified in the global-coordinate system X,Y,Z and define a vector that is in a plane parallel to the x-z plane of the local-coordinate system.
$dXi $dYi $dZi	joint offset values -- absolute offsets specified with respect to the global coordinate system for element-end node i (the number of arguments depends on the dimensions of the current model) (optional)
$dXj $dYj $dZj	joint offset values -- absolute offsets specified with respect to the global coordinate system for element-end node j (the number of arguments depends on the dimensions of the current model) (optional)