Defect detection systems and methods

1. A defect detection system, comprising:

a movement assembly configured and positioned to hold and move a substantially non-conductive structure, the movement assembly comprising:

a first reel device upstream of the sensor assembly and configured to hold a spool of the substantially non-conductive structure; and

a second reel device downstream of the sensor assembly and configured to attach to an end of the substantially non-conductive structure; and

a sensor assembly comprising at least one radar device configured and positioned to detect conductive debris in the substantially non-conductive structure as portions of the substantially non-conductive structure move therepast.

2. The defect detection system of claim 1 , wherein at least a portion of the at least one radar device is located on the same lateral plane as a portion of the substantially non-conductive structure to receive electromagnetic energy from the at least one radar device.

3. The defect detection system of claim 1 , wherein the at least one radar device of the sensor assembly comprises one or more of at least one monostatic radar device and at least one quasi-monostatic radar device.

4. The defect detection system of claim 1 , wherein the at least one radar device comprises a plurality of radar devices.

5. The defect detection system of claim 4 , wherein the plurality of radar devices comprises:

a first radar device laterally adjacent a first side of the substantially non-conductive structure; and

a second radar device laterally adjacent a second side of the of the substantially non-conductive structure opposing the first side.

6. The defect detection system of claim 5 , further comprising a third radar device laterally adjacent the first side of the substantially non-conductive structure.

7. The defect detection system of claim 6 , wherein one or more of the first radar device, the second radar device, and the third radar device is oriented to direct electromagnetic energy into the substantially non-conductive structure at a different angle than at least one other of the first radar device, the second radar device, and the third radar device.

8. The defect detection system of claim 1 , further comprising a marking assembly configured and positioned to mark a location of the conductive debris detected by the sensor assembly along the substantially non-conductive structure.

9. The defect detection system of claim 8 , further comprising a material removal device configured and positioned to remove the conductive debris from the location marked by the marking assembly.

10. The defect detection system of claim 1 , further comprising a support assembly comprising a laterally-extending structure longitudinally underlying the substantially non-conductive structure and comprising a material formulated to block background electromagnetic energy.

11. A defect detection method, comprising:

delivering a substantially non-conductive structure to a defect detection system comprising a movement assembly and a sensor assembly, the substantially non-conductive structure comprising a non-conductive fiber preform infiltrated with a non-conductive slurry;

moving the substantially non-conductive structure through the defect detection system using the movement assembly; and

directing electromagnetic energy into the substantially non-conductive structure from at least one radar device of the sensor assembly to detect conductive debris within the substantially non-conductive structure.

12. The method of claim 11 , further comprising marking a location of the detected conductive debris within the substantially non-conductive structure using a marking assembly of the defect detection system.

13. The method of claim 12 , further comprising removing the detected conductive debris from the substantially non-conductive structure using a material removal device of the defect detection system.

14. The method of claim 11 , wherein directing electromagnetic energy into the substantially non-conductive structure from at least one radar device of the sensor assembly comprises directing the electromagnetic energy into one or more portions of the substantially non-conductive structure from two or more radar devices laterally adjacent the one or more portions of the substantially non-conductive structure.

15. The method of claim 14 , further comprising orienting at least one of the two or more radar devices at a different angle relative to the substantially non-conductive structure than at least one other of the two or more radar devices.

16. The method of claim 11 , wherein directing electromagnetic energy into the substantially non-conductive structure from at least one radar device of the sensor assembly comprises selecting the electromagnetic energy to have a center frequency within a range of from about 9 GHz to about 10 GHz.

17. The method of claim 11 , wherein directing electromagnetic energy into the substantially non-conductive structure from at least one radar device of the sensor assembly to detect conductive debris within the substantially non-conductive structure comprises:

directing radio frequency energy into the substantially non-conductive structure from the at least one radar device; and

receiving at least some of the radio frequency energy reflected off of the conductive debris with the at least one radar device to detect the conductive debris.

18. A defect detection method, comprising:

extending a substantially non-conductive structure between a first reel device and a second reel device of a movement assembly of a defect detection system, the defect detection system comprising the movement assembly and a sensor assembly;

moving the substantially non-conductive structure through the defect detection system using the movement assembly; and

directing electromagnetic energy into the substantially non-conductive structure from at least one radar device of the sensor assembly to detect conductive debris within the substantially non-conductive structure.

19. A method of processing a composite structure, comprising:

pulling a prepreg structure comprising a non-conductive preform infiltrated with a non-conductive slurry from a first reel device;

directing electromagnetic energy into the prepreg structure from a plurality of monostatic radar devices positioned laterally adjacent the prepreg structure to detect conductive debris within the prepreg structure;

marking portions of the prepreg structure containing the detected conductive debris; and

removing the marked portions of the prepreg structure and the detected conductive debris while substantially maintaining a remainder of the prepreg structure.

20. The method of claim 19 , wherein directing electromagnetic energy into the prepreg structure from a plurality of monostatic radar devices positioned laterally adjacent the prepreg structure to detect conductive debris within the prepreg structure comprises:

directing the electromagnetic energy into the prepreg structure from at least one monostatic radar device of the plurality of monostatic radar devices; and

detecting at least some of the electromagnetic energy reflected off of the conductive debris using the at least one monostatic radar device of the plurality of monostatic radar devices.