A method for predicting initial unbalance in a component such as a blisk

摘要

A method for predicting initial unbalance in a component comprising one or more elements, the method comprising: defining a statistical distribution of a mass moment weight of each of the one or more elements; restricting the statistical distribution to a selected range; and calculating an initial unbalance of the component for the restricted distribution of the one or more elements. Where the component is a bladed element, e.g. a blisk, and the elements are blades the predicted initial unbalance is calculated by selecting a plurality of sets of aerofoil elements from the statistical distribution and allocating a location for each aerofoil element on the bladed disk or ring, wherein each set of aerofoil elements forms a sample distribution; and calculating a vector sum of the mass moment weights for each sample distribution to determine the initial unbalance of the blisk. The method is repeated for every permutation of the mass moment weight and/or location of each aerofoil component. A maximum probable unbalance is predicted in order that the size of sacrificial balancing lands of a blisk can be reduced to save weight. The statistical distribution may include a tool wear characteristic.