Correlation of Fir-Tree-Type Turbine-Blade-Fastening Strength With Mechanical Properties of Materials

Some materials under consideration for aircraft gasturbine disks are notch-sensitive at certain operating times, temperatures, and stress levels. Prediction of engine life requires knowledge of the type of mechanical-property test that will correlate with engine life and requires knowledge of the quantitative relationship. Elevated-temperature time-dependent spin tests were run on model disks with fir-tree blade fastenings. Material and test conditions were selected to cover a wide range of notch sensitivity. Results showed that life for tensile mode failures could be predicted from notched rupture tests.