2464. Mass Properties Relational Database Manager – A Primary Element of the Mass Properties Tool Kit

Paper

Abstract

The mass properties tool kit is comprised of four powerful tools. Used together, these tools provide the capability to mathematically model the mass properties of a complex system. The Mass Properties Relational Database Manager tool is a preprocessor data manager. The other three tools sort, sum the mass properties, distribute the mass to finite element grids, and graphically display the data. The Mass Properties Relational Database Manager is the key in a suite of analysis software tools. It serves several purposes. It provides an interactive interface for the entry and maintenance of mass properties data. It is a library of part information. It manages the relationship between parts that build up assemblies. It extracts all this data to create an output file. This file is used as input for the other tools. The Moments of Inertia, Products of Inertia version 3 (MIPI3) mass properties analysis program is made up of several subroutines. They are used to manipulate the mass properties relational database output to obtain the summation of weights, centers of gravity, moments and products of inertia, principle axes, principle inertias, and uncertainties. The MIPI3 program also contains several preprocessors that can be used for sorting the mass properties relational database output to obtain a variety of other outputs. These sorting preprocessors utilize the columns in the mass properties relational database output and arrange that information in a specific order. MIPI3 also has the capability to utilize a transformation of coordinate axes. Therefore, the system is not limited to a rectangular coordinate system, but can also use cylindrical and spherical coordinate systems. The Mass Distribution (MASDIS) mass properties mass distribution program supports finite element structural analysis. This program distributes the mass properties relational database output to a set of finite element grid points. The subroutines divide each component’s mass into pieces of user defined size. A search is then conducted to find the closest node for each subelement of mass. The mass properties of all the subelements are summed at each finite element node. The results are written to an output file in the CONM2 card format. This file serves as an input file for NASTRAN. The Mass Properties Plotter (MPPLOTX) displays the image of the data in the mass properties relational database output. It uses interactive 3-D color graphics and can be used as a visual check that the subject is modeled as intended. Common errors such as misplaced items, improperly sized items, reversed or misoriented shapes, or incorrect shapes can be identified quickly with this tool. It can also display the output of the MASDIS program. This provides a quick validation of the quality of the mass distribution. The mass properties tool kit addresses all phases of mass properties analysis requirements. It is designed to provide sophisticated modeling and visualization capabilities. Based on simple user inputs, the mass properties tool kit provides quick computation and reporting capabilities. This paper addresses only some of the highlights of the Mass Properties Database Manager. It is focused on the use of four basic forms, namely Part, Parts List, Location, and Extract. Emphasis is placed on the ease of using these forms to enter and edit mass properties data. Additional emphasis is placed on the vast capability this tool has in handling coordinate system transformations. An example is shown in the appendix to help illustrate these features. A hypothetical wagon train is used in the example for two reasons. The main reason is to ensure that no company proprietary data is inadvertently leaked in this paper. The other reason is symbolic. Let the pioneering spirit of the western settlers carry you to a better understanding of this new tool. Just as the wagon train led to a new epic in American history, the Mass Properties Relational Database Manager can shift the paradigm of mass properties analysis.