Management of the variability of vibration response levels in mistuned bladed discs using robust design concepts. Part 1: Parameter design

Abstract

Small unavoidable differences (e.g. 5%) between blades on a bladed disc, called mistuning, can lead to a huge variation of forced vibration response levels, and some of them are extremely high (e.g. 500% of the level experienced on every blade is all blades are identical). In this first half of a two-part article, a novel approach of designing a bladed disc with a lower chance of encountering high vibration response levels is evaluated. A robust design concept is applied to manage the variability of the vibration response levels, and the new approach resembles parameter design in Taguchi method of robust design. A “robustness map” is created using simulations results of a 6-degree-of-freedom (6-DOF) system, and such a map is validated by two more complicated models. The robustness map is used to explain the behaviour of bladed discs investigated in previous studies and to give possible methods of delivering more robust bladed disc designs.