M.S. Thesis Presentation by Ashok Chandrasekhar
Thursday, September 9, 1999

(Dr. Fulton, advisor)

"Geometric Interfaces for Analyzable Product Models with Highly Mismatched Design-Analysis Geometry"


CAD design models are typically analyzed across various disciplines such as, structural analysis, thermal analysis and vibration analysis. Further, for a given design model, each analysis discipline may require multiple analysis models. Thus, while every mechanical engineering component typically has one associated CAD model, it can have many associated analysis models. A key step in creating analysis models is to abstract the geometry of the structure that is to be analyzed. Most often, the geometry of the CAD design model is complicated and needs to be simplified and/or idealized for each analysis discipline. Much of this analysis model geometry is often common to, and/or derivable from its CAD model. In cases where there is a high mismatch between CAD geometry and analysis model geometry, the present state of engineering analysis typically requires the analyst to re-create this common and related CAD geometry from scratch in the analysis system. Thus, the associativity between the design model and its analysis models is not explicitly captured.

This study has developed a technique that enables the analyst to selectively choose and extract the attributes of desired geometric entities from CAD models, for the purpose of creating its analysis models. The capabilities of different CAD systems, namely, IDEAS, CATIA and  Pro/Engineer were studied, and the technique was generalized for typical modern CAD systems. The technique was implemented with the CATIA CAD system and tested with several mechanical and aerospace components.  Results show that this technique enables explicit design-analysis associativity and facilitates the engineering analyst to create different analysis model geometry with varying degrees of idealization from the same CAD model.