Modular turbine blade with separate platform support system

Abstract

A modular turbine blade assembly ( 10 ) usable in a gas turbine engine ( 12 ) and formed from an airfoil ( 28 ) and an independent, modular platform ( 16 ) supported by one or more clevis arm supports ( 14 ) extending radially inward from the modular platform ( 16 ) to a disk is disclosed. The clevis arm support may support the modular platform while a separate dovetail attachment supports the generally hollow airfoil. The clevis arm support ( 14 ) may be formed from at least two arms ( 20, 22 ) designed to reduce stress from a pin receiving orifice ( 24 ) at a distal end ( 26 ) of the two arms ( 20, 22 ) to the platform ( 16 ). The independent arms ( 20, 22 ) minimize stress concentrations caused by centrifugal loading in the support. The arms ( 20, 22 ) may be modified independently of each other, such as thickness and support angle. The clevis arm support ( 14 ) enables use of a modular platform system for the modular turbine blade ( 10 ).

1 . A modular turbine blade ( 10 ) of a gas turbine engine comprising:
 a generally elongated hollow airfoil formed from an outer wall, and having a leading edge, a trailing edge, a pressure side, a suction side, and a tip at a first end of the airfoil; and   a modular platform attached to a disc via at least one clevis arm support extending radially inward from the modular platform, wherein the at least one clevis arm support is formed from a first arm and a second arm extending from the modular platform into contact with each other radially inward of the modular platform, wherein a cross member extends between the first and second arms forming an attachment device radially inward of the cross member and between the first and second arms and forming a void between the cross member, the first arm, the second arm and the modular platform.   
     
     
         2 . The modular turbine blade of  claim 1 , wherein the attachment device is a pin receiving orifice. 
     
     
         3 . The modular turbine blade of  claim 1 , wherein at least one intersection of two or more sides forming the cross member, the first arm, and the second arm is rounded. 
     
     
         4 . The modular turbine blade of  claim 1 , wherein inner surfaces of the first arm, the second arm and the cross member are planar inner surfaces. 
     
     
         5 . The modular turbine blade of  claim 1 , wherein a thickness of the first arm differs from a thickness of the second arm. 
     
     
         6 . The modular turbine blade of  claim 1 , wherein the first arm has a cross-sectional area with a width that is greater than a length, and the second arm has a cross-sectional area with a width that is greater than a length. 
     
     
         7 . The modular turbine blade of  claim 1 , wherein the first and second arms are nonorthogonal and nonparallel to each other. 
     
     
         8 . The modular turbine blade of  claim 7 , wherein the first arm is positioned at a different angle relative to a longitudinal axis of the at least one clevis arm support than the second arm. 
     
     
         9 . The modular turbine blade of  claim 1 , wherein first ends of the first and second arms closest to the generally elongated hollow airfoil are further apart than second ends of the first and second arms at the cross member. 
     
     
         10 . The modular turbine blade of  claim 1 , wherein a distal end of the cross member is curved from a first side aligned with the first arm to a second side aligned with the second arm. 
     
     
         11 . The modular turbine blade of  claim 1 , further wherein a center link extending radially inward from the modular platform and positioned between the first and second arms. 
     
     
         12 . The modular turbine blade of  claim 11 , wherein the center link is coupled to the modular platform via a pivot connection.