A Hybrid Non-Contact Ultrasonic System for Sensing Bond Quality in Tow-Placed Thermoplastic Composites

Abstract

A novel non-contact nondestructive evaluation system is proposed for sensing bond quality in tow-placed graphite/PEEK thermoplastic composites. The inspection tool consists of a hybrid ultrasonic system which employs laser generation of narrow-band surface waves with fiberoptic light delivery, and signal detection by air-coupled transduction. The fiberoptic link enhances flexibility and remoteness of the laser source from the test piece. The system output is not influenced by the poor light reflectivity of the test graphite/PEEK material. Signal narrow-banding by light spatial modulation enhances the measurement sensitivity and avoids detrimental material ablation while allowing control of the surface wave penetration depth. The theory of the laser generation of narrow-band surface waves is reviewed and the generation efficiency as a function of the wave propagation direction in the composite is discussed.

The inspection capabilities of the proposed system are demonstrated by successful detection of a series of subsurface defects in a tow-placed unidirectional AS-4/APC-2 cylinder provided by Boeing Commercial Aircraft. The defects examined include regions of poor consolidation, inter-laminar linear porosity (voids elongated along the fibers with 1.5% volume fraction), and delamination or interlaminar weakness. The ultrasonic inspection unit is non-contact, flexible, light-weight and allows for high inspection rates. These characteristics, coupled with a large signal-to-noise ratio of the measurements, show promises for the use of the proposed sensor in on-line control of the thermoplastic tow-placement process with in situ consolidation.

Keywords

non-contact ultrasonic inspection ultrasonic surface waves laser ultrasonics air-coupled transducers thermoplastic tow-placement

Get full access to this article

View all access options for this article.

References

1. Lamontia, M. A. , M. B. Gruber , M. A. Smoot , J. Sloan and J. W. Gillespie, Jr. 1992. Proc. Submarine Technology Symposium, The Johns Hopkins University Applied Physics Laboratory.

2. Lamontia, M. A. , M. B. Gruber , M. A. Smoot , J. Sloan and J. W. Gillespie, Jr. 1995. J. Thermoplastic Composite Materials, 8:15-36.

3. Enders, M. L. and P. C. Hopkins . 1991. Proc. 36th International SAMPE Symposium, pp.767-781.

4. Benjamin, W. P. 1998. SAMPE Journal, 34:10-16.

5. Mantell, S. C. and G. S. Springer . 1992. J. Composite Materials, 26:2348-2377.

6. Nejhad, M. N. , R. D. Cope and S. I. Guceri . 1991. J. Thermoplastic Composite Materials, 4:20-45.

7. Beyeler, E. P. and S. I. Guceri . 1998. J. Heat Transfer, 110:424-430.

8. Grove, S. M. 1988. Composites, 19:3667-3675.

9. Pitchumani, R. S. , S. Ranganathan , R. C. Don and J. W. Gillespie, Jr. 1994. Thermal Processing of Materials: Thermo-Mechanics, Controls, and Composites, V. Prasad et al. , eds., ASME-HTD, 289:223-234.

10.

10. Pitchumani, R. S. , S. Ranganathan , R. C. Don , J. W. Gillespie, Jr. and M. A. Lamontia . 1996. Int. J. Heat and Mass Transfer, 39:1883-1897.

11.

11. Lee, W. I. and G. S. Springer . 1987. J. Composite Materials, 21:1017-1055.

12.

12. Butler, C. A. , R. Pitchumani , J. W. Gillespie, Jr. and A. G. Wedgewood . 1994. Proc. 10th Annual ASM/ESD Advanced Composites Conference, Dearborn, MI, pp. 595-604.

13.

13. Sonmez, F. O. and H. T. Hahn . 1997. J. Composite Materials, 10:543-572.

14.

14. Pitchumani, R. , J. W. Gillespie, Jr. and M. A. Lamontia . 1997. J. Composite Materials, 31:244-275.

15.

15. Heider, D. , M. J. Piovoso and J. W. Gillespie, Jr. 1998. J. Thermoplastic Composite Materials, 11:573-595.

16.

16. Tierney, J. J. , D. Heider and J. W. Gillespie, Jr. 1997. Proc. ANTEC 97, Toronto, Ontario, pp. 1165-1170.

17.

17. Sonmez, F. O. and H. T. Hahn . 1997. J. Composite Materials, 10:381-414.

18.

18. Sarrazin, H. and G. S. Springer . 1995. J. Composite Materials, 29:1908-1943.

19.

19. Duncan, W. and S. C. Mantell . 1993. Proc. 38th International SAMPE Symposium and Exhibition, Anaheim, California, pp. 152-162.

20.

20. Mantell, S. C. , W. Qiuling , and G. S. Springer . 1991. Proc. 26th International SAMPE Symposium and Exhibition, San Diego, California, pp. 1763-1772.

21.

21. Mantell, S. C. , W. Qiuling , and G. S. Springer . 1992. J. Composite Materials, 26:2378-2401.

22.

22. Beloy, J. and S. C. Mantell . 1995. J. Materials Processing and Manufacturing Science, 3:243-256.

23.

23. Beloy, J. and S. C. Mantell . 1994. Proc. ASME International Mechanical Engineering Congress and Exposition, Chicago, Illinois, pp. 1-7.

24.

24. Cling, S. W. , S. C. Mantell , and K. A. Stelson . 1998. J. Dynamic Systems, Measurement and Control—Transactions ASME, 120:507-515.

25.

25. Achenbach, J. D. 1984. Wave Propagation in Elastic Solids. New York, NY: North-Holland Publishing Co., Inc.

26.

26. Rose, J. L. , A. Pilarski and Y. Huang . 1990. Res. in Nondestructive Evaluation, 1:247-265.

27.

27. Bucur, V. and F. Rocaboy . 1988. Ultrasonics, 26:344-347.

28.

28. Chai, J. F. and T. T. Wu . 1994. J. Acoustical Society of America, 95:3232-3241.

29.

29. Lanza di Scalea, F. , B. B. Djordjevic , T. P. Bemdt and R. E. Green, Jr. 1999. Proc. 8th Annual Research Symposium (Automation and Diagnostic in NDE) of the American Society for Nondestructive Testing, Orlando, Florida, p. 137.

30.

30. Mantell, S. C. and E. J. Linstrom . 1999. J. Composite Materials, 33:124-157.

31.

31. Zurn, B. and S. C. Mantell . 1999. Proc. 44th International SAMPE Symposium and Exhibition, Long Beach, California, pp. 1246-1254.

32.

32. Mantell, S. C. , D. Holley and E. J. Linstrom . 1998. Proc. Symposium on Nondestructive Evaluation Techniques for Aging Infrastructure and Manufacturing—SPIE vol. 3399, San Antonio, Texas.

33.

33. Scruby, C. B. and L. E. Drain . 1990. Laser Ultrasonics: Techniques and Applications. Bristol, England: Adam Huger Publishing Co., Inc.

34.

34. Hutchins, D.A. 1988. Physical Acoustics, W.P. Mason and R.N. Thurston , eds., New York, NY: Academic Press, Inc., 18:21-118.

35.

35. Lanza di Scalea, F. and R. E. Green, Jr. 1999. Proc. Society for Experimental Mechanics Spring Conference on Theoretical, Experimental and Computational Mechanics, Cincinnati, Ohio, pp. 407-410.

36.

36. Lanza di Scalea, F. and R. E. Green, Jr. 1999. Experimental Mechanics, 39:329-334.

37.

37. Lanza di Scalea, F. , T. P. Berndt , J. B. Spicer and B. B. Djordjevic . 1999. IEEE Trans. UFFC, 46:1551-1557.

38.

38. Huang, J. , S. Krishnaswamy and J. D. Achenbach . 1992. J. Acoustical Society of America, 92:2527-2531.

39.

39. Harata, A. , H. Nishimura and T. Sawada . 1990. Applied Physics Letters, 57:132-134.

40.

40. Nishino, H. , Y. Tsukahara , Y. Nagata , T. Koda and K. Yamanaka . 1993. Appl. Physics Letters, 62:2036-2038.

41.

41. Nelson, K. A. , R. J. D. Miller , D. R. Lutz and M. D. Fayer . 1982.J. Applied Physics, 53:1144-1149.

42.

42. Wright, W. M. D. , D. W. Schindel and D. A. Hutchins . 1994. J. Acoustical Society of America, 95:2567-2575.

43.

43. Hutchins, D. A. , W. M. D. Wright and D. W. Schindel . 1994. J. Acoustical Society of America, 96:1634-1642.

44.

44. Schindel, D. W. and D. A. Hutchins . 1995. IEEE Trans. UFEC, 42:51-58.

45.

45. Carr, H. and C. Wykes . 1993. Ultrasonics, 31:13-20.

46.

46. Schindel, D. W. and D. A. Hutchins. 1994. US Patent 5,287,331.

47.

47. Schindel, D. W. 1999. Ultrasonics, 37:185-200.

48.

48. Hutchins, D. A. , W. M. D. Wright , G. Hayward and A. Gachagan . 1994. IEEE Trans. UFFC, 41:796-805.

49.

49. Wright, W. M. D. , D. A. Hutchins , A. Gachagan and G. Hayward . 1996. Ultrasonics, 34:825-833.

50.

50. Aindow, A. M. , R. J. Dewhurst and S. B. Palmer . 1982. Optics Comm., 42:116-120.

51.

51. Palmer, D. 1999. Private Communications, Boeing St. Louis, St. Louis, Missouri.

52.

52. Talbott, M. F. , L. A. Berglund and G. S. Springer . 1987. J. Composite Materials, 21:1056-1081.

53.

53. Allison, S. W. , G. T. Gillies , D. W. Magnuson and T. S. Pagano . 1985. Appl. Optics, 24:3140-3145.

54.

54. Skutnik, B. J. , W. B. Beck and M. H. Hodge . 1987. Proc. SPIE, 787:8-16.

55.

55. Bennett, H. A. , A. J. Glass , A. H. Guenther and B. E. Newnam . 1981. Apple. Optics, 20:3003-3019.

56.

56. Caron, J. N. , K. V. Steiner , Y. Yang , and J. B. Mehl . 2000. Materials Evaluation, 58:667-671.

57.

57. Cogswell, F. N. 1992. Thermoplastic Aromatic Polymer Composites. Oxford, England: Butterworth-Heinemann, Ltd.