Evaluation of Interlaminar Shear Strength in Interlayer‐Enhanced Carbon/Epoxy Composites via Short Beam Testing

ABSTRACT

Delamination remains a critical failure mode in aerospace‐grade carbon fiber‐reinforced polymer (CFRP) laminates, often limiting their structural efficiency and long‐term durability. The interlaminar region, dominated by the matrix, constitutes the weakest link, drastically compromising properties such as compressive strength and fatigue life. In this study, the influence of electrospun nanofabric interlayers on the Interlaminar Shear Strength (ILSS) of IM7/8552 carbon/epoxy composites was investigated through Short‐Beam Shear Testing (SBST) according to ASTM D2344. Three types of electrospun nanofabrics were utilized: polyacrylonitrile (PAN), polyamide‐6 (PA6), and polyvinylidene fluoride (PVDF), each containing Multiwall Carbon Nanotubes (MWCNTs), on a weight fraction of W _f =  0.5% . Nanofabrics, were systematically interleaved between every ply of a unidirectional twelve‐ply IM7/8552 laminate, using a proprietary thermo‐compression process prior to autoclave curing. The results demonstrated that PAN and PA6 veils improved the ILSS by 5.38% and 2.61%, respectively, compared to the unmodified reference laminate. Conversely, the non‐polar PVDF veil caused a detrimental reduction of ‐16.88%. The study confirms that the chemical compatibility between the nanofiber polymer and the matrix is the primary factor governing interlaminar performance, offering a reliable pathway for interfacial tailoring in high‐performance structural composites.