Mass Properties question
Mass Properties question
(OP)
Hi, Im trying to calculate the Mass inertia of a tool pivoting on a trunion. Can any explain the difference between these values.
Principal axes of inertia and principal moments of inertia:
Taken at the center of mass.
Moments of inertia:
Taken at the center of mass and aligned with the output coordinate system.
Principal axes of inertia and principal moments of inertia:
Taken at the center of mass.
Units are values: pounds * sq inches
Thanks for any help you may have
Matthew
Principal axes of inertia and principal moments of inertia:
Taken at the center of mass.
Moments of inertia:
Taken at the center of mass and aligned with the output coordinate system.
Principal axes of inertia and principal moments of inertia:
Taken at the center of mass.
Units are values: pounds * sq inches
Thanks for any help you may have
Matthew






RE: Mass Properties question
RE: Mass Properties question
The principal axes of a body are such that the cross coupled terms (Ixy etc) are zero. Typically for a simple symmetrical solid the principal axes are aligned with the 'natural' axes of the body. Even for complex things like a car they are pretty well aligned with the obvious directions.
You need to set up a coordinate system parallel to the axis of rotation, and use that moment of inertia.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.