Flexural Behaviour of Carbon/Glass Intralayer Hybrid Composites: Effects of Hybrid Ratio and Fibre Dispersion

Intralayer hybridisation provides a powerful strategy for tailoring the stiffness–strength–ductility balance of fibre-reinforced composites through architecture control. This study investigates the flexural behaviour of carbon/glass intralayer hybrid composites with varying carbon-to-glass (C:G) ratios and degrees of dispersion using a finite element modelling framework supported by experimental validation against published flexural test data. Four hybrid ratios (C:G = 2:1, 1:1, 1:2, and 1:4) and multiple dispersion levels were examined under three-point bending to quantify the effects of intralayer architecture on flexural strength, modulus, and strain to failure. The results show that carbon-rich hybrids retain high flexural stiffness and strength while achieving substantial improvements in failure strain and damage tolerance compared with pure carbon laminates. In these systems, flexural strength is strongly influenced by dispersion, with moderate-to-high dispersion improving strain compatibility, delaying tensile-side carbon fibre fracture, and enhancing strength. In contrast, glass-dominated hybrids exhibit flexural behaviour that is largely insensitive to dispersion, with strength and modulus following near rule-of-mixtures trends and failure governed by progressive glass fibre and matrix damage. Across all hybrid ratios, flexural modulus is controlled primarily by fibre volume fraction, whereas flexural strength and failure strain depend sensitively on intralayer architecture when carbon fibres remain the dominant load-bearing phase. These findings clarify the respective roles of hybrid ratio and dispersion in governing flexural performance and extend recent studies by demonstrating a systematic transition from dispersion-dominated to ratio-dominated behaviour as glass content increases. The results provide mechanistic insight and practical design guidance for optimising intralayer hybrid composites for lightweight, damage-tolerant structural applications.