PART
The PART command redefines and/or lists the data for a PART statement. Although you cannot redefine the center-of-mass markers, the inertia markers, you are free to move and reorient those markers using the MARKER command. You can also redefine the mass of the part and the 6 values of the inertia tensor.
Format
PART/id [,MASS=r] [,IP=xx,yy,zz [, xy,xz, yz] [,LIST]
[ ] Optionally select the item |
Arguments
IP=xx,yy,zz | Specifies the mass-inertia tensor as computed about the origin of the IM marker, expressed in the coordinate system of the IM marker. You can compute the individual terms of the IP argument as:  In the above formulae, x, y, and z are the components of the displacement of the center of an infinitesimal volume of mass dm, measured from the origin of the inertia marker in the coordinate system of the inertia marker. The integral is performed over the entire volume of the body. If the inertia marker was not specified by the PART statment for the part, the IM marker defaults to the CM marker. In that case, these quantities are computed about the origin of the CM marker in the coordinate system of the CM marker. Note: Adams Solver (C++) defines Ixy, Ixz, and Iyz as positive integrals, as shown. Some references define these terms as the negative of these integrals. Be sure to compute these values as shown above. |
LIST | Lists the current values of the data in the PART statement. |
MASS=r | Respecifies the part mass. |
Caution: | Unlike Adams Solver (FORTRAN) the PART command in Adams Solver (C++) is followed by an initial condition analysis and an integrator restart, if applicable. This is a consequence of the added freedom in respecifying inertia properties and the location and orientation of inertia markers. |
Examples
PART/2, MASS=10
This PART command respecifies the mass of Part 2.
PART/5, IP=0,3,6, LIST
This PART command respecifies the moments of inertia of Part 5 as principal moments of inertia and lists all the data for the Part. If the original definition of Part 5 included an IM marker the moments of inertia are w.r.t. this marker, otherwise the CM marker. If the original definition of Part 5 specified all 6 inertia tensor values, the off-diagonal values are set to zero as a consequence of not being respecified.