2012

Mass properties for all regions
DescriptionMass property
A 2D or 3D coordinate that is the center of area for regions. For re-
gions that are coplanar with the XY plane of the current UCS, this
Centroid
coordinate is a 2D point. For regions that are not coplanar with the
XY plane of the current UCS, this coordinate is a 3D point.
If the regions are coplanar with the XY plane of the current UCS, the additional
properties shown in the following table are displayed.
Additional mass properties for coplanar regions
DescriptionMass property
A value used when computing the distributed loads, such as fluid
pressure on a plate, or when calculating the forces inside a bending
Moments of in-
ertia
or twisting beam. The formula for determining area moments of iner-
tia is
area_moments_of_inertia = area_of_interest * radius
2
The area moments of inertia has units of distance to the fourth power.
Property used to determine the forces causing the motion of an object.
It is always calculated with respect to two orthogonal planes. The
formula for product of inertia for the YZ plane and XZ plane is
Products of iner-
tia
product_of_inertia
YZ,XZ
= mass * dist
centroid_to_YZ
* dist
centroid_to_XZ
This XY value is expressed in mass units times the length squared.
Another way of indicating the moments of inertia of a 3D solid. The
formula for the radii of gyration is
Radii of gyra-
tion
gyration_radii = (moments_of_ inertia/body_mass)
1/2
Radii of gyration are expressed in distance units.
Calculations that are derived from the products of inertia and that
have the same unit values. The moment of inertia is highest through
Principal mo-
ments and
a certain axis at the centroid of an object. The moment of inertia isX,Y,Z directions
about centroid lowest through the second axis that is normal to the first axis and
that also passes through the centroid. A third value included in the
results is somewhere between the high and low values.
MASSPROP | 727