Component lifing

A computer-based method of lifing a mechanical component, the method including performing the steps of:

• (a) providing a model of the component in which the component is divided into a plurality of regions (ra-rf), for each region the model determining a respective cumulative risk (Ra-Rf) which is the probability that the region has a defect multiplied by the probability that that defect causes failure of the component, the cumulative risk (Ra-Rf) being determined by the model for the region as a respective function (Fa(N)-Ff(N)) of a number N of operational cycles of a predetermined standard mission;
• and
• (b) performing consecutively, for each of a consecutive series of actual or virtual missions, the sub-steps of:
• (b-i) determining the number N*a of operational cycles in the most recent actual or virtual mission for each region,
• (b-ii) determining a respective unmodified additional cumulative risk associated with each region F(N*a),
• (b-iii) determining a respective modified additional cumulative risk associated with each region as X·F(N*a), where X is the exchange rate for the combination of the selected region, the actual or virtual mission, and the predetermined standard mission,
• (b-iv) determining an updated total modified cumulative risk associated with each region by adding the modified additional cumulative risk associated with the region to an existing total modified cumulative risk associated with the region due to the previous actual or virtual missions in the series, and
• (b-v) summing the updated total modified cumulative risks of the regions to determine a modified risk of failure of the component.