Composite airfoil with integral platform

Abstract

A method of forming an airfoil with an integrated platform includes: a) providing an airfoil core; b) wrapping a first overwrap ply around the airfoil core; c) darting a first end of the first overwrap ply to allow the overwrap ply to extend perpendicular to the airfoil core to form a first platform; d) filling the darted parts filler plies; e) wrapping a second overwrap ply around the first overwrap ply; f) darting a first end of the second overwrap ply to allow the second overwrap ply to extend adjacent to the first overwrap ply to form the first platform; g) filling the darted parts of the second overwrap ply with one or more filler plies; and h) placing a cap ply in the shape of the platform adjacent to at least one of the first and second overwrap plies. An airfoil with an integrated platform is also disclosed.

1 . A method of forming an airfoil with an integrated platform, the method comprising:
 a) providing an airfoil core;   b) wrapping a first overwrap ply around the airfoil core;   c) darting a first end of the first overwrap ply to allow the overwrap ply to extend at an angle to the airfoil core to form a first platform;   d) filling the darted parts of the first overwrap ply with one or more filler plies;   e) wrapping a second overwrap ply around the first overwrap ply;   f) darting a first end of the second overwrap ply to allow the second overwrap ply to extend adjacent to the first overwrap ply to form the first platform;   g) filling the darted parts of the second overwrap ply with one or more filler plies; and   h) placing a cap ply in the shape of the platform adjacent to at least one of the first and second overwrap plies.   
     
     
         2 . The method of  claim 1 , and further comprising:
 placing a cap ply adjacent to the first overwrap ply to form the surface of the platform flow path.   
     
     
         3 . The method of  claim 1 , wherein steps (b)-(h) are repeated at least one time. 
     
     
         4 . The method of  claim 1 , wherein step (c) further comprises:
 darting a second end of the first overwrap ply to allow it to extend at an angle to the airfoil core to form a second platform.   
     
     
         5 . The method of  claim 4 , wherein step (d) further comprises:
 filling the darted parts of the second overwrap ply with one or more filler plies.   
     
     
         6 . The method of  claim 5 , wherein step (f) further comprises:
 darting a second end of the second overwrap ply to allow it to extend at an angle to the airfoil core adjacent to the first ply to form the second platform.   
     
     
         7 . The method of  claim 6 , wherein step (g) further comprises:
 filling the darted portions of the second end of the second overwrap ply with one or more filler plies.   
     
     
         8 . The method of  claim 7 , wherein step (h) further comprises:
 placing a second cap ply in the shape of the platform adjacent to the second overwrap ply forming the second platform.   
     
     
         9 . The method of  claim 8 , wherein steps (b)-(h) are repeated at least one time. 
     
     
         10 . The method of  claim 1 , where step (a) further comprises:
 wrapping internal plies around the airfoil core; and   inserting filler material.   
     
     
         11 . The method of  claim 10 , wherein the internal plies are extended to form a part of the first platform. 
     
     
         12 . An airfoil with an integrated platform comprising:
 an airfoil core with a leading edge and a trailing edge;   a plurality of overwrap plies extending along the exterior of the airfoil core and extending at an angle to the airfoil body to form a first platform on a first end of the airfoil, wherein the overwrap plies are split in the first platform area to form at least one of a v-dart and a slit dart;   one or more filler plies shaped to fit any v-darts in the overwrap plies; and   a plurality of cap plies connecting adjacent to darted overwrap plies in the first platform.   
     
     
         13 . The airfoil of  claim 12 , and further comprising:
 a second platform formed by darting the overwrap plies on a second end of the airfoil to include at least one of v-darts and slice darts.   
     
     
         14 . The airfoil of  claim 13 , wherein the second platform further comprises:
 one or more filler plies to fit into the areas of the v-darts in the second platform; and   one or more cap plies to fit adjacent to darted overwrap plies in the second platform.   
     
     
         15 . The airfoil of  claim 12 , wherein the darts are locally staggered. 
     
     
         16 . The airfoil of  claim 12 , wherein at least one of the cap plies is located between every two darted plies. 
     
     
         17 . The airfoil of  claim 12 , wherein a cap ply forms the flow path surface on the first platform. 
     
     
         18 . The airfoil of  claim 12 , wherein the airfoil core is a hollow core. 
     
     
         19 . A method of forming an airfoil comprising:
 (a) providing an airfoil core;   (b) wrapping internal plies around the airfoil core;   (c) inserting filler material;   (d) wrapping a first overwrap ply around the internal plies and filler material;   (e) darting the first overwrap ply in one or more places at a first end to allow the first overwrap ply to extend at an angle to the airfoil core to form a first platform;   (f) inserting one or more first filler plies in any darts formed from darting the first overwrap ply;   (g) covering the first overwrap ply with a second overwrap ply;   (h) darting the second overwrap ply in one or more places at the first end to allow it to extend at an angle to the airfoil core adjacent to the first overwrap ply on the first platform;   (i) inserting one or more second filler plies into any darts formed from darting the second overwrap ply; and   (j) attaching a first cover ply in the shape of the first platform adjacent to one or more of the first and second plies.   
     
     
         20 . The method of  claim 19 , wherein steps (d)-(j) are performed a plurality of times. 
     
     
         21 . The method of  claim 19 , wherein the internal plies extend to the first platform. 
     
     
         22 . The method of  claim 21 , wherein the internal plies form a pressure vessel and the filler forms a sharp trailing edge. 
     
     
         23 . The method of  claim 19 , and further comprising:
 (i) darting the overwrap ply in one or more places at a second end to allow it to extend at an angle to the airfoil core to form a second platform;   (j) inserting one or more third filler plies in any darts formed from darting the first overwrap ply at the second end;   (k) darting the second overwrap ply in one or more places at the second end to allow it to extend perpendicular to the airfoil core adjacent to the first overwrap ply on the second platform;   (l) inserting one or more fourth filler plies into any darts formed from darting the second overwrap ply at the second end; and   (m) attaching a second cover ply in the shape of the second platform adjacent to one or more of the first and second plies.   
     
     
         24 . The method of  claim 23 , wherein steps (b)-(m) are performed a plurality of times.