SYNCHRO
SYNCHRO, RATIO, Cname
Specifies whether the excitation frequency is synchronous
or asynchronous with the rotational velocity of a structure.
RATIOIn a stationary reference frame (CORIOLIS with
RefFrame= ON),RATIOis the ratio between the frequency of excitation and the frequency of the rotational velocity of the structure. This value must be greater than 0. The default is an unbalance excitation.In a rotating reference frame (CORIOLIS with
RefFrame= OFF),RATIOis the ratio between the frequency of excitation and the frequency of the rotational velocity of the structure minus 1. This value must be greater than 0. There is no default.CnameThe name of the rotating component on which to apply the harmonic excitation.
Notes
The SYNCHRO command specifies whether the excitation frequency is synchronous or asynchronous with the rotational velocity of a structure in a harmonic analysis. Use the command to take into account rotating harmonic forces on rotating structures.
Mechanical APDL calculates the rotational velocity Ω of the structure from the excitation
frequency f, defined (via the HARFRQ
command) as Ω = 2πf /
RATIO. The rotational velocity is applied along the direction cosines
of the rotation axis (specified via an OMEGA or CMOMEGA
command).
In a stationary reference frame, specifying any value for
RATIO causes a general rotational force excitation and not an
unbalance force. To define an unbalance excitation force (F =
Ω2 * Unb), RATIO should be
left blank (the nodal unbalance Unb is specified via the F
command).
In a rotating reference frame (CORIOLIS with
RefFrame = OFF), an unbalance excitation is a static load;
therefore, a value must be supplied for RATIO.
The SYNCHRO command is valid only for the full harmonic analysis method (HROPT,FULL) and the frequency-sweep harmonic analysis method (HROPT,VT) involving a rotating structure (OMEGA or CMOMEGA) with Coriolis enabled (CORIOLIS).