Corotational Transformation

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This command is used to construct the Corotational Coordinate Transformation (CorotCrdTransf) object. Corotational transformation can be used in large displacement-small strain problems. NOTE: Currently the transformation does not deal with element loads and will ignore any that are applied to the element.


For a two-dimensional problem:

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

For a three-dimensional problem:

geomTransf Corotational $transfTag $vecxzX $vecxzY $vecxzZ



$transfTag integer tag identifying transformation
$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. The local y-axis is defined by taking the cross product of the vecxz vector and the x-axis.

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.

These items need to be specified for the three-dimensional problem.

$dXi $dYi joint offset values -- absolute offsets specified with respect to the global coordinate system for element-end node i (optional)
$dXj $dYj joint offset values -- absolute offsets specified with respect to the global coordinate system for element-end node j (optional)


The element coordinate system is specified as follows:

The x-axis is the axis connecting the two element nodes; the y- and z-axes are then defined using a vector that lies on a plane parallel to the local x-z plane -- vecxz. The local y-axis is defined by taking the cross product of the vecxz vector and the x-axis. The z-axis by taking cross product of x and new y. The section is attached to the element such that the y-z coordinate system used to specify the section corresponds to the y-z axes of the element.


ElementOrentation.gif

RigidElementOffsets.gif


EXAMPLE:

ElementCrossSection.png

ElementOrientation.png

ElementVectors.png

  1. Element 1 : tag 1 : vecxZ = zaxis

geomTransf Corotational 1 0 0 -1

  1. Element 2 : tag 2 : vecxZ = y axis

geomTransf Corotational 2 0 1 0


Code Developed by: Remo Magalhaes de Souza

Images Developed by: Silvia Mazzoni