LOW-ORDER REPRESENTATION OF MANUFACTURING VARIATIONS BASED ON B-SPLINE MORPHING

Even small surface deviations arising from manufacturing may lead to critical performance losses of mechanical components as e.g. blade shape deviations in aeroengines. Supposed that such deviations are often associated with complex geometries, the nominal parametrization of the part may be inadequate to correctly describe them. Therefore, this paper proposes to re-parametrize the surface of interest as a B-spline surface with a higher number of control points to allow accurate coverage of surface deviations. Further, it is demonstrated how such a B-spline surface may be fitted to surface measurements by B-spline morphing and how manufacturing uncertainties may be described statistically by a few manufacturing modes only. Such a small data characterization may be used as an excellent basis for performing robust design. The proposed procedures are validated by an application to the hub endwall of a high-pressure turbine blade.