Investigation of Surface Strains in Fir Tree Turbine Blade Attachments

摘要

Surface strains in the fillet regions of test model specimens of fir tree turbine blade attachments were examined. The fir tree specimens are loaded under cyclic tension-tension in the elastic range. The strains were recorded with an interferometric technique at the center and near the edges of the exposed unloaded face of the fir tree. Data were recorded for a total of over 700 load cycles on 23 different specimens. Two different load bearing surface geometries were investigated. The effect of machining tolerances were determined for both geometries. The load split between the two sets of load bearing surfaces was determined. Actual strains were compared to those predicted by superposition of strain fields. Stresses computed from the recorded strains were compared to photoelastic and finite element analyses. (Author)