Advanced composite materials like carbon-fiber-reinforced-polymer (CFRP) laminates are now widely used in the aerospace
industry due to their outstanding high strength-to-weight ratio and very good rigidity. However, composite structures
are prone to impact damage, which can occur either during the processing stages or during inservice operations. This paper
presents the impact behavior and damage characteristics of CFRP panels at low velocity impact tests over a range of impact
energies. An environmental aging machine and a tensile fatigue method were used to simulate the inservice environmental
aging effects. Cross-section images of impact defect structures from multiple directions were demonstrated and discussed by
utilizing ultrasonic nondestructive evaluation (NDE) method.
1. Poudel, A., J. Strycek, and T.P. Chu, “Air-Coupled Ultrasonic Testing of Carbon/Carbon Composite Aircraft Brake
Disks,” Materials Evaluation, Vol. 71(8), pp. 987-994. 2013.
2. Tomblin, J.S., L. Salah, J.M. Welch and M.D. Borgman, 2004, “Bonded Repair of Aircraft Composite Sandwich
Structures,” DOT/FAA/AR-03/74, Federal Aviation Administration, Office of Aviation Research, Washington, D.C.,
20591. Accessed on: 04/16/2013, Available from: http://www.tc.faa.gov/its/worldpac/techrpt/ar03-74.pdf.
3. Mitchell, K., A. Poudel, S. Li and T.P. Chu, “Nondestructive Evaluation of Composite Repairs,” abstract accepted for
Proceedings of ASNT 2013 Fall Conference, Las Vegas, NV, November 4-7, 2013.
4. Sihn, S., R.Y. Kim, K. Kawabe and S.W. Tsai, “Experimental studies of thin-ply laminated composites,” Composites
Science and Technology, 64 (6) 996-1008, 2007.
5. Graham, D., P. Maasa, G.B. Donaldsona and C. Carr. “Impact damage detection in carbon fiber composites using HTS
SQUIDs and neural networks,” NDT&E International 37, 565-570, 2004.
6. Chu, T.C., A. Leyte, A. DiGregorio, S. Russell and J.L. Walker. “Micro-Cracking Detection in Laminated Composites,”
Proc. of ASNT Spring Conference and 11th Annual Research Symposium, Portland, OR, 2002.
7. Im, K.H., D.K. Hsu and I.Y. Yang, “Inspection of Inhomogeneities in Carbon/Phenolic Matrix Composite Materials
Using NDE Techniques,” Key Engineering Materials, Vols. 270 – 273, pp 1799-1805, 2004.
8. Lee, J.H., S.W. Choi, K.S. Kim, J.H. Park and J.H. Byun, “Nondestructive Characterisation of Carbon/Carbon Brake
Disks Using Ultrasonics,” http://www.ndt.net/article/apcndt01/papers/1109/1109.htm, 2001.
9. Ruosi, A., “Nondestructive detection of damage in carbon fiber composite,” Journal of Physical stat., Vol, 2(5), pp 1153-
1155, March 2005.
10. Bray, D.E. and D. McBride, Nondestructive testing techniques, Wiley-Interscience Publication, John Wiley & Sons, Inc.,
11. Hull, D. and T.W. Clyne, An introduction to composite materials, Cambridge University Press, 1996.
12. Shyr, T.W. and Y.H. Pan, “Impact resistance and damage characteristics of composite laminates,” Composite Structures,
vol. 62, no. 2, pp. 193-203, Nov. 2003.
13. Li, S. and T.P. Chu, 2012, “Ultrasonic 3D Reconstruction of CFRP Panel Delamination,” ASNT Fall Conference, ASNT,
Orlando, FL, October 29-November 1, 2012.