Investigating what Effects Aviation Fluids Have on the Flatwise Compressive Strength of Nomex® Honeycomb Core Material

Authors: G. Kim, R. Sterkenburg

Abstract:

One of the disadvantages of honeycomb sandwich structure is that they are prone to fluid intrusion. The purpose of this study is to determine if the structural properties of honeycomb core are affected by contact with a fluid. The test specimens were manufactured of fiberglass prepreg for the facesheets and Nomex^® honeycomb core for the core material in accordance with ASTM C-365/365M. Test specimens were soaked in several different kinds of fluids, such as aircraft fuel, turbine engine oil, hydraulic fluid, and water for a period of 60 days. A flatwise compressive test was performed, and the test results were analyzed to determine how the contact with aircraft fluids affected the compressive strength of the Nomex^® honeycomb core and how the strength was recovered when the specimens were dry. In addition, the investigation of de-bonding between facesheet and core material after soaking were performed to support the study.

Keywords: Debonding, environmental degradation, honeycomb sandwich structure.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.3300486

References:

[1] Synaszko P, Sałaciński M, Kornas Ł. The Effect of environmental flight conditions on damage propagation in composite sandwich structure. Fatigue of Aircraft Structures. 2015; 2015(7):24-27.
[2] Vavilov V, Marinetti S, Pan Y, Chulkov A. Detecting water ingress in aviation honeycomb panels: Qualitative and quantitative aspects. Polymer Testing. 2016; 54: 270-280.
[3] LaPlante G, Marble AE, MacMillan B, Lee-Sullivan P, Colpitts BG, Balcom BJ. Detection of water ingress in composite sandwich structures: a magnetic resonance approach. NDT & E International. 2005; 38(6):501-507.
[4] Semple KE, Sam-Brew S, Deng J, Cote F, Yan N, Chen Z, Smith GD. Properties of commercial kraft paper honeycomb furniture stock panels conditioned under 65 and 95 percent relative humidity. Forest Products Journal 2015; 65(3-4):106-122.
[5] Foo CC, Chai GB, Seah LK. Mechanical properties of Nomex® material and Nomex® honeycomb structure. Composite Structures. 2007;80(4):588-594. C. J. Kaufman, Rocky Mountain Research Lab., Boulder, CO, private communication, May 1995.
[6] Zinno A, Prota A, Di Maio E, Bakis CE. Experimental characterization of phenolic-impregnated honeycomb sandwich structures for transportation vehicles. Composite structures. 2011;93(11):2910-2924.
[7] Larobina D, Mensitieri G, Aldi A, Calvi E, Iannone M, Manzi F, Nicolais L. An integrated approach to analyze long-term moisture transport in honeycomb-core sandwich panels. Journal of Composite Materials. 2010;44(21):2473-2486.
[8] Herrmann AS, Zahlen PC, Zuardy I. Sandwich structures technology in commercial aviation. Sandwich Structures: Advancing with Sandwich Structures and Materials, Proceedings of the 7th International Conference on Sandwich Structures, Aalborg, 29-31 August 2005. p.13-26.
[9] Kececi E, Asmatulu R. Effects of moisture ingressions on mechanical properties of honeycomb-structured fiber composites for aerospace applications. The International Journal of Advanced Manufacturing Technology 2017;88(1):459-470.
[10] Liu L, Meng P, Wang H, Guan Z. The flatwise compressive properties of Nomex® honeycomb core with debonding imperfections in the double cell wall. Composites Part B: Engineering. 2015;76:122-132.
[11] Edwards AK, Savage S, Hungler PL, Krause TW. Examination of F/A-18 honeycomb composite rudders for disbond due to water using through-transmission ultrasonics. Ultragarsas" Ultrasound". 2011;66(2):36-44.
[12] Roy R, Park SJ, Kweon JH, Choi JH. Characterization of Nomex® honeycomb core constituent material mechanical properties. Composite Structures. 2014;117:255-266.
[13] Davies JM. Lightweight Sandwich Construction. Hoboken, NJ: John Wiley & Sons, 2008.
[14] Yeo ES, Wang J, Mirabella L, Rider AN. Effect of humidity and thermal cycling on carbon-epoxy skin/aramid honeycomb structure. InMaterials Science Forum 2010 (Vol. 654, pp. 2600-2603). Trans Tech Publications.
[15] Fogarty J. Honeycomb core and the myths of moisture ingression. Applied Composite Materials 2010;17(3):293-307.
[16] Radtke TC, Charon A, Vodicka R. Hot/wet environmental degradation of honeycomb sandwich structure representative of F/A-18: Flatwise tension strength. Defence Science and Technology Organisation, MelBourne. 1999.
[17] Hungler PC, Bennett LG, Lewis WJ, Schulz M, Schillinger B. Neutron imaging inspections of composite honeycomb adhesive bonds. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2011;651(1):250-252.
[18] Rider A. The durability of metal-honeycomb sandwich structure exposed to high humidity conditions. Defence Science Technology Organisation Victoria Aeronautical Maritime Research Lab. Fisher Bend. 2002.
[19] Cise DM, Lakes RS. Moisture ingression in honeycomb core sandwich panels: Directional aspects. Journal of Composite Materials. 1997;31(22):2249-2263.
[20] Wang DM, Wang J, Liao QH. Investigation of mechanical property for paper honeycomb sandwich composite under different temperature and relative humidity. Journal of Reinforced Plastics and Composites. 2013;32(13):987-997.
[21] Marble AE, LaPlante G, Mastikhin IV, Balcom BJ. Magnetic resonance detection of water in composite sandwich structures. NDT & E International. 2009;42(5):404-409.
[22] Allred RE, Roylance DK. Transverse moisture sensitivity of aramid/epoxy composites. Journal of Materials Science. 1983;18(3):652-656.
[23] Yin F, Tang C, Li X, Wang X. Effect of moisture on mechanical properties and thermal stability of meta-aramid fiber used in insulating paper. Polymers. 2017;9(10):537.
[24] Kim G, Sterkenburg R, Tsutsui W. Investigating the effects of fluid intrusion on Nomex® honeycomb sandwich structures with carbon fiber facesheets. Composite Structures. 2018;206:535-549.
[25] ASTM C271/C271M-16 Standard Test Method for Density of Sandwich Core Materials, ASTM International, West Conshohocken, PA, 2016.
[26] ASTM C365/C365M-16 Standard Test Method for Flatwise Compressive Properties of Sandwich Cores, ASTM International, West Conshohocken, PA, 2016.
[27] OriginLab. Help Online – LabTalk Programming - Movslope (Internet). (cited 31 August 2018). Available from: https://www.originlab.com/doc/LabTalk/ref/Movslope-func.