3DCS - Three Methods for Modeling Compliant Parts

Three Methods for Modeling Compliant Parts 

Saurav Kakar, Sr. Tolerance Analyst 

Elizabeth F Prentice, Variation Analyst 

There are three methods for locating compliant parts within a model depending on available time and budget, desired accuracy, user experience, and licenses and software.

• Traditional rigid-body moves
• Bend routines based on 3DCS User dlls 
• 3DCS Finite Element Analysis (FEA) Compliant Modeler Addon

 The traditional locating schemes are the quickest, easiest methods requiring about half the time to complete but do not produce as accurate of results when compared to the other two.  We have noted up to a 22% loss in accuracy but that value is part dependent.  

The bend routines, such as the User dll SegmentedBend, require the most amount of time and 3DCS user experience but is generally accurate within 14% of the FEA routine.  Using FEA mesh to locate parts to a target is the most accurate method of predicting variation.  Timing requirements for using FEA in the 3DCS model are between traditional rigid-body and bend-move routines.  We have implemented all three different methods on a section of an aircraft fuselage using equal tolerances and the same measurement points for comparison; detailed results follow. 

Contents: 

• Executive Summary
• Introduction
• Problem 
• Solution
• Timing and Budget
• Desired Accuracy
• User Experience 
• Licenses and Software Requirements
• Example Model Assumptions 
• Summary
• Appendix A 
• Appendix B