3D Connexion Version 6.6

*ROTARY INERTIA

17.20 *ROTARYINERTIA: Deﬁne rigid body rotary inertia.

This option is used to deﬁne rigid body rotary inertia values associated with R OTARYIelements.

Itis also used in ABAQUS/Standard analyses to deﬁne mass proportional damping (for direct-integration

dynamicanalysis) and composite damping (for modal dynamic analysis) associated with ROTARYIelements.

Products: ABAQUS/Standard ABAQUS/Explicit

Type: Model data

Level: Part, Part instance, Assembly

Reference:

•“Rotary inertia,” Section 24.2.1 of the ABAQUS Analysis User’sManual

Required parameter:

ELSET

Setthis parameter equal to the name of the element set containing the ROTARYIelements for which

the value is being given.

Optional parameters:

ALPHA

This parameter applies only to ABAQUS/Standard analys es.

Set this parameter equal to the factor to create inertia prop ortional damping for the

ROTARYI elements when used in direct-integration dynamics. Thi s value is ignored in modal

dynamics. The default is 0.0.

COMPOSITE

This parameter applies only to ABAQUS/Standard analys es.

Set this parameter equal to the fraction of critical damping to be used with the ROTARYI

elements when calculatingcomposite damping factors for the modes when used in modal dynamics.

This value is ignored in direct-integration dynamics. The default is 0.0.

ORIENTATION

Set this parameter equal to the name of an *ORIENTATIONoption (“Orientations,” S ection 2.2.5

of the ABAQUS Analysis User’s Manual) that is being used to deﬁne the d irections of the local axes

for which the rotary inertia values are beinggiven. If the ORIENTATION parameter is omitted, it

is assumed that the components of the inertia tensor are being given with respectto the global axes;

i.e., the global and local inertia axes coincide.

17.20–1

ABAQUS Version 6.1 Module: ID:

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