Wind turbine blade with asymmetrical spar caps

Abstract

A wind turbine blade ( 10 ) with asymmetric spar caps ( 36,38 ). The blade includes a pressure side spar cap ( 36 ) having pressure side fibers ( 56 ) having a pressure side fiber diameter ( 54 ), the pressure side fibers configured to resist a first flap deflection ( 20 ) in a first direction via tensile strength; and a suction side spar cap ( 38 ) having suction side fibers ( 50 ) having a suction side fiber diameter ( 52 ), the suction side fibers configured to resist the first flap deflection via a compressive strength. At a radial cross section, the suction side spar cap exhibits a greater compressive strength and the pressure side spar cap, for example, by the suction side fibers having a different compressive strength than the pressure side fibers.

The invention claimed is: 
     
         1 . A wind turbine blade comprising:
 a pressure side spar cap comprising pressure side fibers comprising a pressure side fiber diameter, the pressure side fibers configured to resist a first flap deflection of the blade in a first direction via tensile strength; and   a suction side spar cap comprising suction side fibers comprising a suction side fiber diameter, the suction side fibers configured to resist the first flap deflection via a compressive strength;   wherein at a radial cross section the suction side fibers comprise a different compressive strength than the pressure side fibers.   
     
     
         2 . The wind turbine blade of  claim 1 , wherein the suction side fibers exhibit a greater compressive strength than the pressure side fibers. 
     
     
         3 . The wind turbine blade of  claim 1 , wherein the pressure side fibers comprise fibers of a first diameter, the suction side fibers comprise fibers of a second diameter, and wherein the second diameter is greater than the first diameter. 
     
     
         4 . The wind turbine blade of  claim 3 , wherein the second diameter is greater than 20 micrometers. 
     
     
         5 . The wind turbine blade of  claim 3 , wherein the second diameter falls within a range from 25 micrometers to 34 micrometers, inclusive. 
     
     
         6 . The wind turbine blade of  claim 1 , wherein the pressure side fibers comprise a first mixture of fiber types, each type comprising a distinct diameter, and wherein the suction side fibers comprise a second mixture of fiber types different than the first mixture of fiber types. 
     
     
         7 . The wind turbine blade of  claim 1 , wherein the pressure side fibers comprise fibers of a first composition and the suction side fibers comprise fibers of a second composition different than the first composition. 
     
     
         8 . The wind turbine blade of  claim 1 , wherein the first fiber composition comprises glass fiber, and wherein the second fiber composition comprises carbon fiber. 
     
     
         9 . The wind turbine blade of  claim 1 , wherein the pressure side fibers comprise a first mixture of fiber types, each type having a distinct composition, and wherein the suction side fibers comprise a second mixture of fiber types different than the first mixture of fiber types. 
     
     
         10 . The wind turbine blade of  claim 1 , wherein the suction side fibers and the pressure side fibers comprise plural fiber types, wherein each of the plural fiber types comprises a distinct combination of diameter and composition, wherein the pressure side fibers comprise a first mixture of fiber types, and wherein the suction side fibers comprise a second mixture of fiber types different than the first mixture of fiber types. 
     
     
         11 . A wind turbine blade, comprising:
 a spar, comprising:
 a pressure side spar cap comprising pressure side fibers configured to resist a first flap deflection in a first direction; 
 a suction side spar cap comprising suction side fibers configured to resist the first flap deflection; 
 a spar web configured to hold the pressure side spar cap and the suction side spar cap in a spaced-apart relationship; 
   a pressure side shell comprising the pressure side spar cap; and   a suction side shell comprising the suction side spar cap,   wherein the pressure side fibers and the suction side fibers comprise at least one of a plurality of different diameters and a plurality of different compositions, and   wherein at a given radial cross section the suction side fibers comprise a greater compressive strength than the pressure side fibers.   
     
     
         12 . The wind turbine blade of  claim 11 , wherein a diameter of the pressure side fibers is less than or equal to 20 micrometers, and a diameter of the suction side fibers are greater than 20 micrometers. 
     
     
         13 . The wind turbine blade of  claim 11 , wherein the pressure side spar cap comprises glass fibers and the suction side spar cap comprises carbon fibers. 
     
     
         14 . The wind turbine blade of  claim 11 , wherein the pressure side spar cap comprises a first mixture of carbon fibers and glass fibers and the suction side spar cap comprises a comprises a second, different mixture of carbon fibers and glass fibers. 
     
     
         15 . A wind turbine blade, comprising:
 a pressure side spar cap comprising pressure side fibers; and   a suction side spar cap comprising suction side fibers;   wherein for a given radial location along the blade, cross sections of the pressure side spar cap and the suction side spar cap are asymmetric; and   wherein the suction side cross section comprises a greater compressive strength than the pressure side cross section.   
     
     
         16 . The wind turbine blade of  claim 15 , wherein the suction side cross section comprises a larger area than the pressure side cross section. 
     
     
         17 . The wind turbine blade of  claim 15 , wherein the suction side fibers comprise a larger diameter than the pressure side fibers. 
     
     
         18 . The wind turbine blade of  claim 15 , wherein a composition of the suction side fibers comprises a greater compressive strength than a composition of the pressure side fibers. 
     
     
         19 . The wind turbine blade of  claim 15 , wherein matrix material in the suction side cross section comprises a greater compressive strength than matrix material in the pressure side cross section.