|Home | ADCATS Info | Search | Site Map | Bulletin Board | Reports & Publications | Bibliography | Contact Us|
2001 Conference Presentations
Tolerance Analysis of Flexible Assemblies
Michael Tonks, Brigham Young University
Traditional methods of statistical tolerance analysis cannot account for deformations or stresses due to assembly of flexible parts. A flexible tolerance analysis method that combines statistical tolerance analysis with finite element analysis is being developed at BYU. It features a statistical finite element solution, which can predict the range of internal displacements, forces, and stresses due to assembly.
The statistical solution involves determining a covariance matrix that describes the interdependence of any two nodes in the FEA model. Three methods for determining the covariance matrix have been developed. Each of these methods characterizes the surface variation in a different form and they differ in their ability to model the wavelength of surface variations. The results given by each of these methods compare favorably with the results given from a Monte Carlo simulation. Additionally, while the Monte Carlo method takes thousands of calls to the FEA model, these methods take only two FEA calls.
Currently the method that best characterizes the wavelength variation cannot accurately analyze wavelengths longer then the part length. Current research is being done to create a hybrid method that can characterize wavelength variation and handle long wavelengths. Research is also being done to verify these methods on actual production assemblies.
|The ADCATS site: Home | ADCATS Info | Search | Site Map | Bulletin Board | Reports & Publications | Bibliography | Contact Us|