Modal expression of form defects

Abstract

In the fields where the form is functional, the qualification of shape defects is essential to optimize the functional conditions. By using the geometrical tolerances as defined in the standards, the behavior of surfaces inside this space may not be defined (or characterized). To meet specific needs, one of the research orientations consists in correlating the measured defects with the origin of these defects, by generating a basis of characteristic defects. After a brief review of the methods of shape defects analysis, a decomposition based on the dynamic natural modes of their ideal surface is suggested. The method is explained, then applied on a simple example, and compared to the decomposition in the basis of the Zernike polynomials. The article concludes on an opening from the possibilities and the research orientations to consider. © 2007 Springer.