Method and apparatus for the remote nondestructive evaluation of an object

Abstract

A method and apparatus for the remote nondestructive evaluation of an object such as a wind turbine blade involves applying mechanical and/or thermal stress to the object and then scanning the object using long-range thermographic and/or laser interferometric imaging. The laser interferometric imaging is preferably performed by a long range shearography camera capable of imaging deformation derivatives at long distances coupled with a blade stressing mechanism incorporating either thermal or internal blade pressurization for the purpose of detecting remotely and at high speed, changes in the structural integrity of an installed wind turbine blade.

What is claimed is: 
     
         1 . A method of testing structural integrity of a wind turbine blade, comprising steps of:
 pressurizing an internal space of a wind turbine blade;   sensing a property of the wind turbine blade that is dependent upon internal pressurization to obtain data; and   analyzing the data.   
     
     
         2 . A method of testing structural integrity of a wind turbine blade according to  claim 1 , wherein the step of pressurizing comprises coupling pressurization equipment to the internal space of the wind turbine blade. 
     
     
         3 . A method of testing structural integrity of a wind turbine blade according to  claim 2 , wherein the pressurization equipment comprises an air blower. 
     
     
         4 . A method of testing structural integrity of a wind turbine blade according to  claim 1 , wherein the pressurization is sufficient to cause crack opening. 
     
     
         5 . A method of testing structural integrity of a wind turbine blade according to  claim 4 , wherein the pressurization relative to ambient pressure conditions is substantially within a range of about 0.01 psi to about 10 psi. 
     
     
         6 . A method of inspecting a wind turbine blade, comprising steps of:
 stressing at least a portion of the wind turbine blade; and   scanning at least a portion of the wind turbine blade using laser interferometric imaging.   
     
     
         7 . A method of inspecting a wind turbine blade according to  claim 6 , wherein the step of stressing at least a portion of the wind turbine blade comprises applying a mechanical stress to at least a portion of the wind turbine blade. 
     
     
         8 . A method of inspecting a wind turbine blade according to  claim 7 , wherein the step of applying the mechanical stress comprises creating a pressure differential between an internal space defined within the wind turbine blade and external ambient pressure conditions. 
     
     
         9 . A method of inspecting a wind turbine blade according to  claim 8 , wherein the pressure differential comprises a positive pressurization within the internal space. 
     
     
         10 . A method of inspecting a wind turbine blade according to  claim 9 , wherein the positive pressurization relative to ambient conditions is substantially within a range of about 0.01 psi to about 10 psi. 
     
     
         11 . A method of inspecting a wind turbine blade according to  claim 10 , wherein the positive pressurization relative to ambient conditions is substantially within a range of about 0.02 psi to about 7 psi. 
     
     
         12 . A method of inspecting a wind turbine blade according to  claim 11 , wherein the positive pressurization relative to ambient conditions is substantially within a range of about 0.05 psi to about 3.5 psi. 
     
     
         13 . A method of inspecting a wind turbine blade according to  claim 6 , wherein the step of stressing at least a portion of the wind turbine blade comprises applying a thermal stress to at least a portion of the wind turbine blade. 
     
     
         14 . A method of inspecting a wind turbine blade according to  claim 13 , wherein the step of applying a thermal stress to at least a portion of the wind turbine blade comprises applying radiation to a least a portion of the wind turbine blade. 
     
     
         15 . A method of inspecting a wind turbine blade according to  claim 6 , wherein the method is performed in a wind turbine blade fabrication facility. 
     
     
         16 . A method of inspecting a wind turbine blade according to  claim 6 , wherein the method is performed in situ. 
     
     
         17 . A method of inspecting a wind turbine blade, comprising steps of:
 applying a stress to at least a portion of the wind turbine blade;   thermographically imaging the portion of the wind turbine blade; and   analyzing the thermographic image.   
     
     
         18 . A method of inspecting a wind turbine blade according to  claim 17 , wherein the stress is a thermal stress. 
     
     
         19 . A method of inspecting a wind turbine blade according to  claim 17 , wherein the step of applying a stress to a least a portion of the wind turbine blade comprises applying radiation to a least a portion of the wind turbine blade. 
     
     
         20 . A method of inspecting a wind turbine blade according to  claim 19 , wherein the step of applying radiation to at least a portion of the wind turbine blade comprises applying infrared radiation. 
     
     
         21 . A method of inspecting a wind turbine blade according to  claim 19 , wherein the step of applying radiation to at least a portion of the wind turbine blade comprises applying microwave radiation. 
     
     
         22 . A method of inspecting a wind turbine blade according to  claim 19 , wherein the step of applying radiation to at least a portion of the wind turbine blade comprises projecting radiation over a distance that is substantially within a range of about 50 feet to about 1500 feet. 
     
     
         23 . A method of inspecting a wind turbine blade according to  claim 22 , wherein the step of applying radiation to at least a portion of the wind turbine blade comprises projecting radiation over a distance that is substantially within a range of about 100 feet to about 1000 feet. 
     
     
         24 . A method of inspecting a wind turbine blade according to  claim 23 , wherein the step of applying radiation to at least a portion of the wind turbine blade comprises projecting radiation over a distance that is substantially within a range of about 200 feet to about 700 feet. 
     
     
         25 . A method of inspecting a wind turbine blade according to  claim 17 , further comprising imaging at least a portion of the wind turbine blade using laser interferometric imaging. 
     
     
         26 . A method of inspecting a wind turbine blade according to  claim 25 , wherein the step of imaging at least a portion of the wind turbine blade using laser interferometric imaging comprises shearography. 
     
     
         27 . A method of inspecting a wind turbine blade according to  claim 17 , wherein the stress is a mechanical stress. 
     
     
         28 . A method of inspecting a wind turbine blade according to  claim 27 , wherein the mechanical stress is a vibrational stress.