CompuServe Thread

#Moment of Inertia

2 messages in this thread
#28801From: RICHARD MINTZLAFFJan 15, 1992 4:53 PM
CarlThe first thing I tried was to use AME, but got erroneous solutions. I wasn't aware that the calculations are based on the current UCS. You must have to have the origin at the corner of the I beam or sometihing like that. Anyway, I received another reply and downloaded a lisp file called 2dcm.lsp which works great. I would be interested in what the rules are for using AME for moment of inertia calculations, if you have any caveats they would be helpful. By the way does AME compute polar moments of inertia? Thanks again, Rick
#28806From: Ashim Guha [ADESK]Jan 15, 1992 5:25 PM
Richard, You seemd to have made a common mistake, while computing mass properties in AME. In AME R1, we calculate MASS moments of inertia, which applies to any object with volume,3d solids. It is different from AREA moments of inertia, which apply to 2d objects. Polar moment of inertia is the summation of area moments of inertia in X & Y directions. When calculating MASS moments of inertia, the results depends on where your current UCS is. But they, are accurate about any UCS, since we use Parallel axis theorem to do the necessary transformation. AME R2 will address your need for AREA moments of inertia. If you have any further problems, with MASS property values, I am willing to look into it & resolve it satisfactorily. Ashim.