Pro/Engineer August 2004 Tip-of-the-Month
A Quick Validation of Assembly Mass Properties Calculations
Figure 1 shows the Model Analysis dialog box after a mass properties calculation has been done. The Results section shows the calculated information. A quick look at Average Density can give a sanity check for the Mass value given, however, for a more detailed look, it is often a good idea to double check the assigned materials and densities of the components.
To get that closer look, you can scroll around in the results window, or, press the Info button. If you press the Info button, another window like the one shown in Figure 2 will pop up. It contains all the same information as in the Results section of the dialog box, but in a larger window for easier reading.
Scroll down through the INFORMATION window. The last section is labeled MASS PROPERTIES OF COMPONENTS OF THE ASSEMBLY. An example is shown in Figure 2. The information is somewhat jumbled together, but the left most column is the density of each component (average density for each subassembly). The right most column is the assigned material file name.
(Note: The material file name listed here is not the same as the material condition name written about for the July 2004 Tip-of-the-Month. The material condition does not appear here.)
A quick scan of the densities will show any that are out of range. In Figure 2, the 3rd item, named LCH-BARB-END has a density that is several orders of magnitude smaller (... e-05) than the others. This is a good indicator that something is not assigned correctly. Another indicator is a value of 1.0000.
In Figure 2, a quick scan of the materials column (right side) shows the assigned materials. Anything labeled UNKNOWN is worth a closer look. For the LCH-BARB-END, no material was assigned. The other one with an UNKNOWN material is LCH-RELEASE, which is a sub-assembly. All sub-assemblies will have an UNKNOWN material.
It would be nice if Pro/E would allow a quick drill down capability, or even an indicator that the component is a sub-assembly, but they do not. You just have to know that, then open the sub-assembly to do the same kind of model analysis.
This is a pretty easy way of assuring that all the materials are assigned correctly so you have confidence in the mass properties calculations.