LIGHTWEIGHT TURBINE BLADE ATTACHMENT

PROPOSED HEREIN IS A PROGRAM TO DEVELOP AN IMPROVED METHOD FOR TURBINE BLADE DISK ATTACHMENTS. A DESIGN CONCEPT IS PRESENTED TO ALLOW EASY REMOVAL AND REPLACMENT OF BLADES, REDUCE THE MASS OF THE ATTACHMENT REGION, AND MAINTAIN THE STRUCTURAL RELIABILITY OF STANDARD FIR-TREE AND DOVETAIL ENTRY ROOT DESIGN. THE "SPLIT ROOT" CONCEPT COMBINES THE INSTALLATION FEATURES OF AN AXIAL TYPE BLADE ROOT, WITH THE RIGIDITY AND STRENGTH OF A LESS MASSIVE STRADDLE MOUNT ROOT. THE SPLIT TOOT BLADE IS FASTENED AXIALLY ON THE DISK, WITH DIRECT CONTACT BETWEEN ADJOINING BLADE ROOT SURFACES FOR INCREASED MATERIAL DAMPING. PINS INSERTED AXIALLY BETWEEN ADJOINING ROOT FACES MAINTAIN BLADE RIGIDITY, AND PROVIDE ADDITIONAL DAMPING. ADVANTAGES OF THE SPLIT ROOT DESIGN ARE PRESERVATION OF THE AXIAL ENTRY INSTALLATION PROCEDURE, REDUCE BLADE TOOT MASS WITHOUT LOSS OF STRENGTH OR RIGIDITY, INCREASED BLADE DAMPING, LOWER DYNAMIC STRESS, AND EXTENDED BLADE LIFE. BY REDUCING MASS AND INCREASING DAMPING, THE SPLIT ROOT DESIGN MAY ALSO ALLOW SIMPLIFICATION OF THE ATTACHMENT GEOMETRY, WHICH WILL FURTHER EASE INSTALLATION AND REMOVAL OF THE BLADES, AS WELL AS REDUCE THEIR ASSOCIATED MANUFACTURING COSTS.