Compressive strength of aluminum honeycomb core sandwich panels with thick carbon–epoxy facesheets subjected to barely visible indentation damage

Abstract

An experimental study of damage tolerance under quasi-static indentation (QSI) was performed for sandwich composite panels consisting of 16-ply carbon–epoxy facesheets bonded to an aluminum honeycomb core. To determine how indentation damage and compression strength after indentation depend on the facesheet layup, three facesheet stacking sequences were used, varying the maximum ply angle change and placement of the outermost 0° ply. Similarly, to determine the effect of core parameters on damage and strength following indentation, three cores with varying density and thickness were studied. Specimens were indented in QSI to the barely visible indentation damage threshold by spherical indenters of 25.4 or 76.2 mm diameters. Damaged specimens were tested to failure in compression to determine the post-indentation compressive strength and resulting failure mode. Compression-after-indentation (CAI) strength is compared to the undamaged strength obtained from edgewise-compression tests of specimens with the same geometry type. Three distinct failure modes were observed in the CAI experiments: compressive fiber failure, delamination buckling and global instability. Post-indentation compressive strength was independent of indenter size and there was no clear propensity for a particular failure mode dependent on a given specimen geometry. Specimens with a high core density and facesheets with a primary ply angle change of 90° were found to be the most damage resistant. Specimens with facesheets having the outer 0° plies closest to the center of the laminate were found to be the most damage tolerant.

Keywords

Sandwich composites compression after impact low velocity impact barely visible impact damage quasi-static indentation

Get full access to this article

View all access options for this article.

References

Kassapoglou

Jonas

Abott

. Compressive strength of composite sandwich panels after impact damage: an experimental and analytical study. J Compos Technol Res 1988; 10: 65–73.

Abrate

. Localized impact on sandwich structures with laminated facings. Appl Mech Rev 1997; 50: 69.

Cantwell

Scudamore

Ratcliffe

. Interfacial fracture in sandwich laminates. Compos Sci Technol 1999; 59: 2079–2085.

Tomblin J, Lacy T, Smith B et al. Review of damage tolerance for composite sandwich airframe structures. Washington, DC: Federal Aviation Administration, 1999. DOT/FAA/AR-99/49.

Shyprykevich P, Tomblin J, Ilcewicz L et al. Guidelines for analysis, testing, and nondestructive inspection of impact-damaged composite sandwich structures. Washington, DC: Federal Aviation Administration, 2003. DOT/FAA/AR-02/121.

Lacy T, Samarah I and Tomblin J. Damage resistance characterization of sandwich composites using response surfaces. Washington, DC: Federal Aviation Administration, 2002. DOT/FAA/AR-01/71.

Davies

GAO

Hitchings

Besant

. Compression after impact strength of composite sandwich panels. Compos Struct 2004; 63: 1–9.

Tomblin J, Raju K, Walker T et al. Damage tolerance of composite sandwich airframe structures – additional results. Washington, DC: Federal Aviation Administration; 2005. DOT/FAA/AR-05/33.

Ratcliffe J and Jackson W. A finite element analysis for predicting the residual compression strength of impact-damaged sandwich panels. Hampton, VA: National Aeronautics and Space Administration, 2009. NASA/TM-2008-215341.

10.

Moody C and Vizzini A. Damage tolerance of composite sandwich structures. Washington, DC: Federal Aviation Administration; 2000. DOT/FAA/AR-99/91.

11.

Xie

Vizzini

Yang

On residual compressive strength prediction of composite sandwich panels after low-velocity impact damage. In: Thomsen

Bozhevolnaya

Lyckegaard

(eds). Sandwich structures 7: advancing with sandwich structures and materials, The Netherlands: Springer, 2005, pp. 363–372.

12.

Zhou

Hill

Hookham

. Investigation of parameters governing the damage and energy absorption characteristics of honeycomb sandwich panels. J Sandwich Struct Mater 2007; 9: 309–342.

13.

Williamson

Lagace

. Response mechanisms in the impact of graphite/epoxy honeycomb sandwich panels. In: Proc of 8th Tech Conf of American Society of Composites 1993, pp. 287–297. Lancaster, PA: Technomic Publishing AG.

14.

Nettles

Jackson

. Compression after impact testing of sandwich composites for usage on expendable launch vehicles. J Compos Mater 2010; 44: 707–738.

15.

Czabaj

Zehnder

Davidson

. Compressive strength of honeycomb-stiffened graphite/epoxy sandwich panels with barely-visible indentation damage. J Compos Mater 2014; 48: 2455–2471.

16.

Minguet PJ. A model for predicting the behavior of impact-damaged minimum gage sandwich panels under compression. In: Proceedings of the AIAA/ASME/ASCE/AHS/ASC 32th Structural dynamic and material conference, Baltimore, MD, AIAA-91-1075-CP, 8-10 April, 1991, pp.1112–1122.

17.

Kassapoglou

. Buckling, post-buckling and failure of elliptical delaminations in laminates under compression. Compos Struct 1988; 9: 139–159.

18.

Noor

Burton

Bert

. Computational models for sandwich panels and shells. Appl Mech Rev 1996; 49: 155–199.

19.

Waas

Schultheisz

. Compressive failure of composites, Part II: experimental studies. Progr Aerosp Sci 1996; 32: 43–78.

20.

Singh

Davidson

Hasseldine

. Damage resistance of aluminum core honeycomb sandwich panels with carbon/epoxy face sheets. J Compos Mater 2014; 49(23): 2859–2876.

21.

Hexcel Corporation. HexPly® 8552 epoxy matrix product data sheet, 2013. Available at: http://www.hexcel.com/Resources/prepreg-data-sheets.

22.

Herup

Palazotto

. Low-velocity impact damage initiation in graphite/epoxy/Nomex honeycomb-sandwich plates. Compos Sci Technol 1998; 57: 1581–1598.

23.

Ferri

Sankar

. A comparative study on the impact resistance of composite laminates and sandwich panels. J Thermoplast Compos Mater 1997; 10: 304–315.

24.

Singh

Davidson

Eisenberg

. Damage characterization of quasi-statically indented composite sandwich structures. J Compos Mater 2013; 47: 1211–1229.

25.

Singh AK. Damage characterization and analytical modeling of quasi-statically indented graphite/epoxy-honeycomb core composite sandwich structures. PhD Thesis, Syracuse University, Syracuse, NY, 2013.

26.

ASTM Standard C364/C364M-07: Standard test method for edgewise compressive strength of sandwich constructions. West Conshohocken, PA: ASTM International; 2007.

27.

Post

Han

Ifju

. Moiré methods for engineering and science: moiré interferometry and shadow moiré. Photomechanics 2000; 196: 151–196.

28.

Kim

Jun

. Impact resistance of composite laminated sandwich plates. J Compos Mater 1992; 26: 2247–2261.

29.

Hong

Liu

. On the relationship between impact energy and delamination area. Experiment Mech 1989; 29: 115–120.

30.

Jelf

Fleck

. Compression failure mechanisms in unidirectional composites. J Compos Mater 1992; 26: 2706–2726.

31.

Hsiao

Daniel

. Effect of fiber waviness on stiffness and strength reduction of unidirectional composites under compressive loading. Compos Sci Technol 1996; 56: 581–593.

32.

Lee

Soutis

. A study on the compressive strength of thick carbon fibre/epoxy laminates. Compos Sci Technol 2007; 67: 2015–2026.

33.

Czabaj M. Damage and damage tolerance of high temperature composites and sandwich composite structures. PhD Thesis, Cornell University, Ithaca, NY, 2010.