2025/02/20 by Szpoganicz, Eduardo, Hübner, Fabian, Beier, Uwe +2
#620 #CFRP composites #Cryogenics #Delamination #Ply thickness #Shear strength
paper · doi:10.15495/epub_ubt_00008245
This study investigates the effect of prepreg ply thickness on the intralaminar toughness and shear strength of carbon-fiber reinforced polymer (CFRP) in room temperature and cryogenic environments. A toughened epoxy resin, optimized for ultra-low temperatures, was impregnated with unidirectional carbon-fibers at 45, 70, and 140 g/m² areal weights. The intralaminar energy release rates in modes I and II, along with the interlaminar shear strength, were evaluated under liquid nitrogen (in-situ) testing conditions to assess the performance of these composites in cryogenics. Optical and scanning electron microscopy correlated fiber-matrix distribution and regularity with failure modes and performance. While GIC decreased from 296 K to 77 K, ILSS was notably higher in cryogenic environments. Both intralaminar toughness and interlaminar strength were improved by thinner plies, especially at 77 K. Thus, highlighting the importance of fiber-matrix uniformity in optimizing delamination and shear properties under cryogenic conditions, where sensitivity to irregularities increases.