CMDOMEGA
CMDOMEGA, CM_NAME, DOMEGAX, DOMEGAY, DOMEGAZ, X1, Y1, Z1, X2, Y2, Z2
Specifies the rotational acceleration of an element component
about a user-defined rotational axis.
CM_NAME,The name of the element component.
DOMEGAX,DOMEGAY,DOMEGAZIf the
X2,Y2,Z2fields are not defined,DOMEGAX,DOMEGAY, andDOMEGAZspecify the components of the rotational acceleration vector in the global Cartesian X, Y, Z directions.If the
X2,Y2,Z2fields are defined, onlyDOMEGAXis required.DOMEGAXspecifies the scalar rotational acceleration about the rotational axis. The rotational direction ofDOMEGAXis designated either positive or negative, and is determined by the "right hand rule."If
DOMEGAX= “DELETE” andCM_NAMEis empty, the component-wise rotational acceleration is removed from all components. All other fields are ignored.X1,Y1,Z1If the
X2,Y2,Z2fields are defined,X1,Y1, andZ1define the coordinates of the beginning point of the rotational axis vector. Otherwise,X1,Y1, andZ1are the coordinates of a point through which the rotational axis passes.X2,Y2,Z2The coordinates of the end point of the rotational axis vector.
Notes
Specifies the rotational acceleration components DOMEGAX, DOMEGAY, and DOMEGAZ of an element component CM_NAME about a user-defined rotational axis. The rotational axis can be
defined either as a vector passing through a single point, or a vector
connecting two points.
You can define the rotational acceleration and rotational axis with the CMDOMEGA command for these analyses:
Loads for VT and Krylov methods are supported as long as they are not:
complex tabulated loads (constant or trapezoidal loads in tabulated form are supported)
used in conjunction with Rotordynamics (CORIOLIS,on).
In a mode-superposition harmonic or transient analysis, you must apply the load in the modal portion of the analysis. Mechanical APDL calculates a load vector and writes it to the MODE file, which you can apply via the LVSCALE command.
Rotational velocities are combined with the element mass matrices to form a body force load vector term. Units are radians/time2.
The CMDOMEGA command supports tabular boundary conditions
(%TABNAME_X%, %TABNAME_Y%, and
%TABNAME_Z%) for DOMEGAX, DOMEGAY, and
DOMEGAZ input values (*DIM) for full
transient and harmonic analyses. In this case, if the end point is
specified (X2, Y2,
Z2), the rotational velocity axis must be along the global X-, Y-,
or Z-axis.
Related commands are ACEL, CGLOC, CGLOC, OMEGA, CMOMEGA, DCGOMG, DOMEGA.
See Analysis Tools in the Theory Reference for more information.
You can use the CMDOMEGA command in conjunction with any one of the following two groups of commands, but not with both groups simultaneously:
Components for which you want to specify rotational loading must consist of elements only. The elements you use cannot be part of more than one component, and elements that share nodes cannot exist in different element components. You cannot apply the loading to an assembly of element components.
See Acceleration Effect in the Mechanical APDL Theory Reference for more information.
This command is also valid in PREP7.