NairnFEAMPM Icon

Rotate Command

The Rotate command has different uses for FEA calculations and for MPM calculations.

Rotate in FEA Calculations

The Rotate command in FEA analyses rotates the coordinates for all nodes near a line or for a single node:

Rotate (axis),(angle)

where

Once rotated, a Displacement command can apply a skewed displacement boundary condition. Rotations do not affect load or stress boundary conditions. Note that each node can only be rotated once. If you rotate two intersecting lines or paths, the code will take care to rotate the intersecting node only once.

Rotate in MPM Calculations

The Rotate command in MPM analyses rotates material axes to define the initial orientation when using anisotropic materials:

Rotate (axis),(angle),<(axis),(angle)2>...

where multiple pairs of a arguments can be used to define one to three rotations. In each pair

MPM Notes

  1. Rotate commands can only used with Region blocks or within BMPRegion blocks (in MPM only). The reset, however, can only be used in Region blocks.
  2. You apply rotations in order by using one to three commands. There are two physical pictures:
  3. All single and double angle rotations are allowed (x, y, z, xy, xz, yx, yz, zx, and zy). When doing three rotations, the only schemes currently supported are zyx and zyz. It is easy to add more if needed (or to rearrange coordinates to make one of these work).
  4. 2D calculations only allow z axis rotation (which is θ axis if axisymmetric), which can be done with either an angle option in the Region command or a single Rotate z,angle command. You will need to use the Rotate command option if you want to set the angle with a user-defined function.
  5. Use of any Rotate commands within a Region block will override any angle setting in the Region command (i.e., that specified angle will be ignored).
  6. Use of any Rotate commands within a BMPRegion block will override any Angle setting in an Intensity command. Furthermore the chosen rotation angles will apply to all material points defined in the current BMPRegion block. Finally, if the BMPRegion block defines an angle-mask file, that file will override all Rotate commands.