RESULTS TRANSFORM Transform Datum

                        

This command requests the transformation of results from a defined local system to the global system, into a local system and also the calculation of results relative to a datum. The datum may be a node, or in the case of relative displacements, it may be a line specified by two nodes or a plane defined by three nodes.

Transform Datum Comments

GLOBAL ON or OFF Transform results from local to global. Default is OFF. (See note 1.)

LOCAL LINE [AUTO]/[HOLD] Stresses are transformed to a local co-ordinate system on a line (see note 2).

XSECTION [AUTO]/[HOLD] Stresses are transformed to a local co-ordinate system on a plane cross section (see note 3).

CONICAL name comp 'name' identifies the coordinate

CYLINDRICAL name comp system to be used and 'comp' defines

RECTANGUL name comp the component of the local system to be

SPHERICAL name comp displayed. 'comp' can be RR/XX, HH/YY, ZZ, RH/XY, HZ/YZ or ZX. (see note 4.)

OFF The local transformation is turned off.

RELATIVE NODE n1 The result value at the specified node is subtracted from all results (see note 5).

LINE n1 n2 Result values are given relative to a line (see note 6).

PLANE n1 n2 n3 Result values are given relative to a plane (see note 7).

VALUE value The specified value is subtracted from all results.

OFF The relative transformation is turned off.

Note that the RESULTS TRANSFORM command will be switched off if another results attribute/component is selected, but remains active if the loadcase is changed.

Notes:

1.

Transformation from a local system to the global system
Certain analysis packages give specific results in a local coordinate system and will provide the necessary transformation matrix to transform from local to global. If all this information is available then FEMVIEW will perform the transformation when requested by this command and, if results are to be presented as vectors, then the directions will be transformed to the global system irrespective of this command.

2.

Transformation of stresses to a local line
The local system will be defined such that `n1' to `n2' (or cursor hit 1 to cursor hit 2) define the local x-direction, the local y-direction is in the plane of the screen and the local z-direction out of the screen.

The AUTO control means that a new transformation will be calculated for each new line. The HOLD control means that the existing transformation will be applied to subsequent lines, and a new transformation not calculated.

3.

Transformation of stresses to a local cross section
The local system will be defined in one of two ways depending on how the cross section was defined in FEMVIEW . If the cross section was defined by three nodes, then the direction of `n1' to `n2' will define the local x-direction, a normal from the local x-direction to `n3' will define the local y-direction; and the local z-direction will be determined according to the right hand screw rule for an orthogonal system.

If the cross section was defined using the graphics cursor, then the direction of cursor hit 1 to cursor hit 2 will define the local x-direction; the local y-direction is defined by a normal to the plane of the screen (+ve into the screen); and the local z-direction determined as before.

The AUTO control means that a new transformation will be calculated for each new cross section. The HOLD control means that the existing transformation will be applied to subsequent cross sections, and a new transformation not calculated.

4.

Results stored with local system If the results being transformed have been stored in the database with a local coordinate system, the results will be transformed into the global system before being transformed into the coordinate system specified.

5.

Results relative to a node
This datum can only be used with nodal results.

6.

Results relative to a line
This datum can only be used with nodal vector quantities and with certain result presentation modes.

A transformation is calculated such that node `n1' will have zero displacement. The transformation incorporates a rotation (if necessary) such that node `n2' is made to lie on the line. The transformation is applied to all results.

7.

Results relative to a plane
This datum can only be used with nodal vector quantities and with certain result presentation modes.

A transformation is calculated such that node `n1' will have zero displacement. The transformation incorporates a rotation (if necessary) such that node `n2' is made to lie on the line `n1' `n2', and `n3' is made to lie on the plane defined by the three nodes. The transformation is applied to all results.