Block Format Keyword Apply a centrifugal force on a set of nodes according a body rotational velocity around the defined direction.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
fct_IDT Dir frame_ID sens_ID grnod_ID Ivar Ascalex Fscaley

## Definitions

Field Contents SI Unit Example

(Integer, maximum 10 digits)

unit_ID Unit Identifier

(Integer, maximum 10 digits)

(Character, maximum 100 characters)

fct_IDT Time function identifier, giving the rotational velocity $\omega$ versus time.

(Integer)

Dir Direction of rotation (input XX, YY or ZZ)

(Text)

frame_ID Frame identifier
= 0
Rotation is expressed in global reference system
0
Rotation is expressed with respect to the frame.

(Integer)

sens_ID Sensor identifier.

(Integer)

grnod_ID Node group to which the load is applied.

(Integer)

Ivar Flag to disregard variation of velocity with respect to time, for the calculation of the force.
= 1 (Default)
Variation of velocity is not taken into account.
= 2
Variation of velocity is taken into account.

(Integer)

Ascalex Abscissa scale factor.

Default = 1.0 (Real)

$\left[\text{s}\right]$
Fscaley Ordinate scale factor.

Default = 1.0 (Real)

$\left[\frac{\text{rad}}{\text{s}}\right]$

1. A force is computed corresponding to a body rotational velocity around the direction Dir of the global reference system if frame_ID = 0, or the reference system defined by the frame if frame_ID ≠ 0.
2. This option is not a kinematic condition (velocity of the nodes is not specified).
3. If frame_ID = 0, the force applied to the node of mass $m$ , at location $M$ is computed as:(1)
$F=m\left(\frac{d\omega }{dt}\wedge OM+\omega \wedge \omega \wedge OM\right)$

If Ivar = 1:

$\frac{d\omega }{dt}\wedge OM$ is not taken into account.(2)
$F=m\left(\omega \wedge \omega \wedge OM\right)$
4. If frame_ID0, the force applied to a node is computed as: (3)
$F={f}_{r}+{f}_{e}+{f}_{c}$
Driving force:(4)
${f}_{e}=m\left(\gamma \left(A\right)+\left(\frac{d{\Omega }_{\left(R\text{'}/R\right)}}{dt}\right)\wedge AM+{\Omega }_{\left(R\text{'}/R\right)}\wedge \left({\Omega }_{\left(R\text{'}/R\right)}\wedge AM\right)\right)$
Coriolis force:(5)
${f}_{c}=m\left(2{\Omega }_{\left(R\text{'}/R\right)}\wedge v{\left(M\right)}_{/R\text{'}}\right)$
Relative force:(6)
${f}_{r}=m\left(\frac{d\omega }{dt}\wedge AM+\omega \wedge \omega \wedge AM\right)$

If Ivar = 1:

$\frac{d\omega }{dt}\wedge AM$ is not taken into account in relative force.

(7)
${f}_{r}=m\left(\omega \wedge \omega \wedge AM\right)$
Where,
R
Global reference system
R'
Reference system defined by the frame
A
Origin of the frame
M
A point of the defined group of node
${\Omega }_{\left(R\text{'}/R\right)}$
Rotational velocity of the frame with respect to the global reference system
$\omega$
Rotational velocity defined by the time function