Local Bending Containment in Sandwich Panels with Sub-surface Core Damage

Abstract

A simple repair technique to contain the local facesheet bending in sandwich panels with sub-surface core damage has been explored using experiments. The strategic filling of honeycomb cells in the damage region using polymeric resin has been used to repair impact/ indentation damaged sandwich panels. The effectiveness of repair was measured using edgewise compression tests. The test results indicate that the best bending containment is achieved by filling a honeycomb cell at the center of the damage region and at the periphery of the damage region along the line of potential failure. The residual strengths of repaired sandwich panels improved to 87—92% of that of the undamaged panel.

Keywords

sandwich damage repair.

References

Vinson, J.R. (1999). The Behavior of Sandwich Structures of Isotropic and Composite Materials, SAGE Publications, Lancaster, PA.

Abrate, S. (1998). Impact on Composite Structures, Cambridge University Press, Cambridge UK.

Tomblin, J. , Lacy, T. , Smith, B. , Hooper, S. , Vizzini, A. and Lee, S. (1999). Review of Damage Tolerance for Composite Sandwich Airframe Structures, Final Contract Report DOT/FAA/AR-99/49.

Tomblin, J.S. , Salah, L. , Borgman, M. and Welch, J. (2004). Bonded Repair of Aircraft Composite Sandwich Structures , DOT/FAA/AR-03/74, February 2004.

Raju, M. , Reddy, C.R. , Swamy, M.R.N. , Giridhar, G. , Srikanth, L. , Prakash, M.R. and Rao, R.M.V. G. K. (2006). Repair Effectiveness Studies on Impact Damaged Sandwich Composite Constructions, Journal of Reinforced Plastics and Composites, 25(1): 5-16.

Tsang, P.H.W. and Lagace, P.A. (1994). Failure Mechanisms of Impact-Damaged Sandwich Panels under Uniaxial Compression, AIAA-94-1396-CP, Proceedings of the AIAA/ASME/ASCE/AHS/ASC 35th Structures, Structural Dynamics and Materials Conference, Hilton Head, SC, USA.

Tomblin, J.S. , Raju, K.S. , Liew, J. and Smith, B.L. (2001). Impact Damage Characterization and Damage Tolerance of Composite Sandwich Airframe Structures, Final Contract Report DOT/FAA/AR-00/44.

Tomblin, J.S. and Raju, K.S. (2002). Impact Damage Characterization and Damage Tolerance of Composite Sandwich Airframe Structures - Phase II, Final Report, DOT/FAA/AR-02/80, September 2002.

Soutis, C. and Hu, F.Z. (2007). Design and Performance of Bonded Patch Repairs of Composite Structures, Journal of Aerospace Engineering , 211(4): 263-271.

10.

Zimmerman, K. and Liu, D. (1995). Geometrical Parameters in Composite Repairs, Journal of Composite Materials, 29(11): 1473-1487.

11.

Hamoush, S. , Sivakumar, K. , Darwish, F. , Sharpe, M. and Swindell, P. (2005). Defective Repairs of Laminated Solid Composites, Journal of Composite Materials , 39(24): 2185-2196.

12.

Cytec Engineered Materials Inc. , 4300 Jackson Street, Greenville, Texas 75401, USA.

13.

Hexcel , 6400 West 5400 South Salt Lake City, Utah 84118, USA.

14.

Hexion Speciality Chemicals, 1600 Smith Street, 24th Floor, P.O. Box 4500, Houston, TX 77210-4500, USA.

15.

RDP Electrosense, 2216 Pottstown Pike, Pottstown, PA 19465, USA.

16.

Vishay Intertechnology, Inc., 63 Lancaster Avenue, Malvern, PA 19355-2143, USA.