2011

Mass properties for all regions
DescriptionMass property
The total length of the inside and outside loops of a region. The
perimeter of a solid is not calculated.
Perimeter
The two coordinates that define the bounding box. For regions that
are coplanar with the XY plane of the current user coordinate system,
Bounding box
the bounding box is defined by the diagonally opposite corners of a
rectangle that encloses the region. For regions that are not coplanar
with the XY plane of the current UCS, the bounding box is defined
by the diagonally opposite corners of a 3D box that encloses the re-
gion.
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 solid. The for-
mula 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.
MASSPROP | 1075