Article Article
Ultrasonic Porosity Measurement in Carbon Fiber Epoxy Laminates

In this research, through-transmission ultrasonic (TTU) Acoustography was applied to measure and quantify porosity levels in carbon fiber reinforced plastic (CFRP) composite laminates. This study employed several CFRP specimens with wide ranges of porosity prepared by altering the curing pressure during the processing stage. The Acoustography method, operating at 5 MHz and 3.8 MHz, was able to show contrast in ultrasonic images obtained for composite laminates with varied porosity levels. Porosity levels in composite laminates were quantified using acid digestion technique. Also, 3-point bending tests were conducted to investigate the effect of porosity in composite laminates. From the results obtained, it was demonstrated that the mechanical property, inter-laminar shear strength (ILSS), of CFRP decreased with the increasing void content. In addition, ultrasonic attenuation in CFRP laminates were related to varied porosity levels. These findings are significant because Acoustography is being developed as a faster alternative to traditional ultrasonic inspection of composites and porosity is an important anomaly to quantify utilizing NDE methods.

  1. Poudel, A., Li, S., Chu, T. P., Palmer, D., and Engelbart, R., "An intelligent Systems Approach for Detecting Delamination Defects due to Impact Damage in CFRP Panel by Using Ultrasonic Testing," Proc. ASNT Fall Conference, ASNT.
  2. Poudel, A., Strycek, J., and Chu, T. P., 2013, "Air-Coupled Ultrasonic Testing of Carbon/Carbon Composite Aircraft Brake Disks," Materials Evaluation, 71(8), pp. 987-994.
  3. Demma, A., and Djordjevic, B. B., "Effects of porosity on the Mechanical Strength and Ultrasonic Attenuation of CF-Peek Fibre Placed Composites " Proc. 15th WCNDT,
  4. Hsu, D. K., and Uhl, K. M., 1987, "A Morphological Study of Porosity Defects in Graphite-Epoxy Composites," Review of Progress in Quantitative Nondestructive Evaluation, 6B, pp. 1175-1184.
  5. Stone, D. E. W., and Clarke, B., 1975, "Ultrasonic Attenuation As a Measure of Void Content in Carbon- Fibre Reinforced Plastics," Non-Destructive Testing, 8(3), pp. 137-145.
  6. Costa, M. L., Almeida, F. M., and Rezende, M. C., 2001, "The influence of porosity on the interlaminar shear strength of carbon/epoxy and carbon/bismaleimide fabric laminates," Composites Science and Technology, 61(14), pp. 2101-2108.
  7. Liu, L., Zhang, B., Wu, Z., and Wang, D., 2005, "Effect of Cure Pressure Induced Voids on the Mechanical Strength of Carbon/Epoxy Laminates," Science Technology, 21(1), pp. 87-91. 16.5 17 17.5 18 18.5 19 19.5 20 0.000 0.500 1.000 1.500 2.000 2.500 3.000 ILSS (Mpa) Porosity Content (%) ILSS Vs Porosity Content 133
  8. Ancelotti, A. C., Pardini, L. C., Bezerra, E. M., and Roach, D., 2010, "Use of the Mar-Lin Criteria to Determine the influence of Porosity on the Iosipescu and Short Beam Shear Properties in Carbon Fiber Polymer Matrix Composites," Materials Research, 13(1), pp. 63-69.
  9. Hong-yan, Z., Di-hong, L., Dong-xing, Z., Bao-chang, W., and Yu-yong, C., 2009, "Influence of voids on interlaminar shear strength of carbon/epoxy fabric laminates," Transactions of Nonferrous Metals Society of China, 19(2), pp. s470-s475.
  10. Muller de Almeida, S. F., and Neto, Z. d. S. N., 1994, "Effect of void content on the strength of composite laminates," Composite Structures, 28(2), pp. 139-148.
  11. Liu, L., Zhang, B.-M., Wang, D.-F., and Wu, Z.-J., 2006, "Effects of cure cycles on void content and mechanical properties of composite laminates," Composite Structures, 73(3), pp. 303-309.
  12. Poudel, A., Sandhu, J. S., Chu, T. P., and Pergantis, C., "Porosity Measurement in Carbon Fiber Epoxy Laminates by Using Acoustography," Proc. 23rd Annual Research Symposium and Spring Conference, ASNT.
  13. Sandhu, J. S., 1988, "Acoustography: A New Imaging Technique and its Applications to Nondestructive Evaluation," Materials Evaluation, 46(5), pp. 608-&.
  14. Sandhu, J. S., 1995, Nondestructive Testing Handbook, American Society for Nondestructive Testing, Columbus, OH.
  15. Sandhu, J. S., Wang, H. H., Popek, W. J., and Sincebaugh, P., 1999, "Acoustography: A Side-by-Side Comparison With Conventional Ultrasonic Scanning," Nondestructive Evaluation of Aging Materials and Composites Iii, G. Y. Baaklini, C. A. Lebowitz, and E. S. Boltz, eds., pp. 163-172.
  16. Composites, M. R. C. F. a., 2010, "Newport 321 Product Data Sheet PL.NB321.071910," Mitsubishi Rayon Carbon Fiber and Composites, Inc., Irvine, CA.
  17. ASTM D3171-11, Standard Test Methods for Constituent Content of Composite Materials," 2013,, West Conshohocken, PA.
  18. ASTM D2344 / D2344M-13, Standard Test Method for Short-Beam Strength of Polymer Matrix Composite Materials and Their Laminates," 2013,, West Conshohocken, PA.
  19. Ling, L., Boming, Z., Zhanjun, W., and Dianfu, W., 2005, "Effects of Cure Pressure Induced Voids on The Mechanical Strength of Carbon/Epoxy Laminates," Journal of Materials Science & Technology, 21(1), pp. 87-91.
Usage Shares
Total Views
283 Page Views
Total Shares
0 Tweets
0 PDF Downloads
0 Facebook Shares
Total Usage