Methods of non-destructive testing and ultrasonic inspection of composite materials

1. A method of non-destructive testing, the method comprising:

locating an ultrasonic transducer with respect to a component having a visually-inaccessible structure to collect B-scan data from at least one B-scan of the component and to collect C-scan data from at least one C-scan of the component;

filtering the B-scan data and the C-scan data to remove random noise and coherent noise based on predetermined geometric information about the visually-inaccessible structure to obtain filtered data; and

performing linear signal processing and nonlinear signal processing to determine a damage index for a plurality of voxels representing the visually-inaccessible structure from the filtered B-scan data and the filtered C-scan data.

2. The method of claim 1 wherein the predetermined geometric information comprises a layer thickness of the visually-inaccessible structure.

3. The method of claim 1 further comprising generating ea volume visualization as a V-scan image of V-scan data from the damage index.

4. The method of claim 3 wherein generating the volume visualization comprises assigning each voxel falling below a threshold damage value a color value based on a location of the voxel to provide a three-dimensional effect to the V-scan image.

5. The method of claim 3 further comprising extracting a three-dimensional contour from the V-scan data and calculating a strength of the component based on the volume visualization or the three-dimensional contour.

6. The method of claim 1 wherein the visually-inaccessible structure comprises a fiber composite.

7. The method of claim 1 wherein the visually-inaccessible structure comprises a composite laminate.

8. The method of claim 1 wherein the component comprises a wind turbine blade and the visually-inaccessible structure comprises a spar cap.

9. The method of claim 1 further comprising quantifying at least one characteristic of at least one feature of the visually-inaccessible structure selected from the group consisting of a location of waviness, a depth of waviness, a length of waviness, and an aspect ratio of waviness of the feature.

10. An ultrasound system comprising:

at least one ultrasonic transducer; and

a computer operatively connected to the ultrasonic transducer, wherein the computer is configured to:

direct the ultrasonic transducer to conduct at least one B-scan and collect B-scan data from the at least one B-scan and to conduct at least one C-scan and collect C-scan data from the at least one C-scan of a component comprising a visually-inaccessible structure;

filter the B-scan data and the C-scan data to remove random noise and coherent noise based on predetermined geometric information about the visually-inaccessible structure to obtain filtered data; and

perform linear signal processing and nonlinear signal processing to determine a damage index for a plurality of voxels representing the visually-inaccessible structure from the filtered B-scan data and the filtered C-scan data.

11. The ultrasound system of claim 10 wherein the computer is further configured to quantify at least one characteristic of the visually-inaccessible structure selected from the group consisting of a location of out-of-plane waviness, a depth of out-of-plane waviness, a length of out-of-plane waviness, and an aspect ratio of waviness.

12. A method of non-destructive testing, the method comprising:

locating an ultrasonic transducer with respect to a component having a visually-inaccessible structure to collect B-scan data from at least one B-scan of the component and to collect C-scan data from at least one C-scan of the component;

filtering the B-scan data and the C-scan data to remove random noise and coherent noise based on predetermined geometric information about the visually-inaccessible structure to obtain filtered data;

performing linear signal processing and nonlinear signal processing to determine a damage index for a plurality of voxels representing the visually-inaccessible structure from the filtered B-scan data and the filtered C-scan data;

generating a volume visualization as a V-scan image of V-scan data from the damage index; and

clustering the plurality of voxels based on damage index values and characterizing at least one feature in the visually-inaccessible structure as a debonded feature or a waviness feature by distinguishing a debonded state and a waviness state of the visually-inaccessible structure.

13. The method of claim 12 wherein the predetermined geometric information comprises a layer thickness of the visually-inaccessible structure.

14. The method of claim 12 wherein generating the volume visualization comprises assigning each voxel falling below a threshold damage value a color value based on a location of the voxel to provide a three-dimensional effect to the V-scan image.

15. The method of claim 12 wherein the waviness feature comprises an out-of-plane waviness.

16. The method of claim 12 further comprising performing a data compression comprising defining contour levels of clustered voxels, setting a contour threshold value for contour lines, defining a contour of a 3-D image in x-y, x-z, and y-z planes at each clustered voxel group, and compiling the contours into a single contour image comprising the contours.

17. The method of claim 12 further comprising quantifying at least one characteristic of at least one feature of the visually-inaccessible structure selected from the group consisting of a location of waviness, a depth of waviness, a length of waviness, and an aspect ratio of waviness of the feature.

18. The method of claim 12 further comprising extracting a three-dimensional contour from the V-scan data.

19. The method of claim 18 further comprising calculating a strength of the component based on the volume visualization or the three-dimensional contour.

20. An ultrasound system comprising:

at least one ultrasonic transducer; and

a computer operatively connected to the ultrasonic transducer, wherein the computer is configured to:

direct the ultrasonic transducer to conduct at least one B-scan and collect B-scan data from the at least one B-scan and to conduct at least one C-scan and collect C-scan data from the at least one C-scan of a component comprising a visually-inaccessible structure;

filter the B-scan data and the C-scan data to remove random noise and coherent noise based on predetermined geometric information about the visually-inaccessible structure to obtain filtered data;

perform linear signal processing and nonlinear signal processing to determine a damage index for a plurality of voxels representing the visually-inaccessible structure from the filtered B-scan data and the filtered C-scan data;

generate a volume visualization as a V-scan image of V-scan data from the damage index;

extract a three-dimensional contour from the V-scan data; and

determine a presence of debonding or waviness of the visually-inaccessible structure from the volume visualization or the three-dimensional contour.

21. The ultrasound system of claim 20 wherein the computer is further configured to quantify at least one characteristic of the visually-inaccessible structure selected from the group consisting of a location of out-of-plane waviness, a depth of out-of-plane waviness, a length of out-of-plane waviness, and an aspect ratio of waviness.