This study investigates one-sided thermal damage of carbon fiber reinforced polymers (CFRP) by means of depth resolved infrared spectroscopy, tomography and mechanical testing. All CFRP samples are thermally irradiated at one side with a heat flux of 50 kW/m2 over various time intervals. ATR-FTIR spectroscopy along a ground incline plane through the sample allows a chemical characterization of the thermal degradation of the polymer matrix into depth. Developing delaminations are observed with a depth-resolved gray-value-analysis of microfocused computed X-ray tomographic (µCT) data. Mechanical behavior is determined by tensile, compressive, and interlaminar shear strength (ILSS) testing of specimens taken from different depths of the irradiated samples. The depth profiles show how pronounced damage phenomena like matrix degradation and the development of delaminations are after one-sided thermal loading and how they influence strength in different ways. Compressive strength and ILSS is found to be more sensitive towards thermal damage than tensile strength, as they are most influenced by formed delaminations at higher thermal loads.
SchürmannH. Konstruieren mit Faser-Kunststoff-Verbunden, 2nd ed. New York: Springer, 2007.
2.
WangYCWongPMHKodurV. An experimental study oft the mechanical properties of fibre reinforced polymer (FRP) and steel reinforcing bars at elevated temperatures. Compos Struct2006; 80: 131–140.
3.
McCombeGPRouseJTraskRS, et al.X-ray damage characterization in self-healing fibre reinforced polymers. Compos Part A Appl Sci Manuf2012; 43: 613–620.
4.
WolfrumJEiblSLietchL. Rapid evaluation of long-term thermal degradation of carbon fibre epoxy composites. Compos Sci Technol2009; 69: 523–530.
5.
BondzicSHodgkinJKrstinaJ, et al.Chemistry of thermal ageing in aerospace epoxy composites. J Appl Polym Sci2006; 100: 2210–2219.
6.
DaoBHodgkinJKrstinaJ, et al.Accelerated aging versus realistic aging in aerospace composite materials. II. Chemistry of thermal aging in a structural composite. J Appl Polym Sci2006; 102: 3221–3232.
7.
WolfrumJWhitneyEEiblS. Approaches to understand and predict the influence of rapid heat-up on degradation and strength of carbon fibre polymer matrix composites. J Compos Mater2016; 51: 2435–2447.
8.
Product Data Sheet HexPly® 8552, Hexcel Inc, www.hexcel.com (2016, accessed 24 March 2020).
9.
EiblS. Influence of carbon fibre orientation on reaction-to-fire properties of polymer matrix composites. Fire Mater2011; 36: 309–324.
10.
LéonardFSteinJSoutisC, et al.The quantification of impact damage distribution in composite laminates by analysis of X-ray computed tomograms. Compos Sci Technol2017; 152: 139–148.
11.
DIN EN 2563. Carbon fibre reinforced plastics – Unidirectional lamintes – Determination of the apparent interlaminar shear strength. German version, 1997-03.
12.
DIN EN 2561. Carbon fibre reinforced plastics – Unidirectional lamintes – Tensile test parallel to the fibre direction. German version; 1995-11.
13.
DIN EN ISO 14126. Fibre reinforced plastic composites – Determination of compressive properties in the in-plane direction. German version, 2000-12.
14.
Seggewiß P. Experimentelle und numerische Untersuchung des Verhaltens kohlenstofffaserverstärkter Epoxidmatrix-Systeme unter einseitiger thermischer und gleichzeitiger mechanischer Belastung. PhD Thesis, Universität der Bundeswehr München, 2011.
15.
Schuster T. Einfluss von Carbon Nanotubes auf die funktionellen und strukturellen Eigenschaften von kohlenstofffaserverstärkten Kunststoffen. PhD Thesis, Universität der Bundeswehr München, 2015.
EiblS. Observing inhomogeneity of plastic components in carbon fiber reinforced polymer materials by ATR-FTIR spectroscopy in the micrometer scale. J Compos Mater2008; 42: 1231–1246.
18.
EiblS. Reliable and universally applicable chemometric techniques based on infrared spectroscopy to non-destructively quantify thermal damage of carbon fibre reinforced epoxy matrix composites. Polym Test2019; 76: 396–410.
19.
GünzlerHGremlichHU. IR-Spektroskopie – eine Einführung, 4th ed. Weinheim: Wiley-VCH, 2003.
20.
ColinXMaraisCVerduJ. A new method for predicting the thermal oxidation of thermoset matrices – Application to an amine crosslinked epoxy. Polym Test2001; 20: 795–803.
21.
FeihSMouritzA. Tensile properties of carbon fibres and carbon fibre-polymer composites in fire. Compos Part A Appl Sci Manuf2012; 43: 765–772.
22.
OlivierLBaudetCBertheauD, et al.Development of experimental, theoretical and numerical tools for studying thermo-oxidation of CFRP composites. Compos Part A Appl Sci Manuf2009; 40: 1008–1016.
23.
WolfrumJQuanEMaierG, et al.Damage initiation of thermally degraded carbon composites in tension. J Compos Mater2018; 52: 3399–3409.
24.
McManusHLNSpringerGS. High temperature thermomechanical behavior of carbon-phenolic and carbon-carbon composites, II. Results. J Compos Mater1992; 26: 230–255.
25.
SwansonDWolfrumJ. Time to failure modeling of carbon fiber reinforced polymer composites subject to simultaneous tension and one-sided heat flux. J Compos Mater2018; 52: 2503–2514.
26.
AnkaraAGökçe DaraBWeisgerberD. The thermal response of CFRP structures. J Thermoplast Compos Mater2003; 16: 317–331.
27.
PeringGAFarrellPVSpringerGS. Degradation of tensile and shear properties of composites exposed to fire or high temperature. J Compos Mater1980; 14: 54–68.
28.
LiuJZhuXZhouZ, et al.Effects of thermal exposure on mechanical behavior of carbon fiber composite pyramidal truss core sandwich panel. Compos Part B Eng2014; 60: 82–90.
29.
MouritzAPGibsonAG. Fire properties of polymer composite materials, Dordrecht, Netherlands: Springer, 2006, pp. 53–54.
30.
LeeJSoutisC. A study on the compressive strength of thick carbon fibre-epoxy laminates. Compos Sci Technol2007; 67: 2015–2026.
31.
SethiSRathoreDKRayBC. Effects of temperature and loading speed on interface-dominated strength in fibre/polymer composites: an evaluation for in-situ environment. Mater Des2015; 65: 617–626.
32.
EiblS. Potential for the formation of respirable fibers in carbon fiber reinforced plastic materials after combustion. Fire Mater2017; 41: 808–816.
33.
DaraIHAnkaraAAkovaliG, et al.Heat-damage assessment of carbon-fiber-reinforced polymer composites by diffuse reflectance infrared spectroscopy. J Appl Polym Sci2005; 96: 1222–1230.
