Amos Ichenihi

Thin-ply hybrid laminates of glass and carbon fibers have been widely adopted in engineering pseudo-ductility. In this study, a Finite Element model is proposed using Abaqus to predict pseudo-ductility in thin-ply laminates consisting of three materials. These materials comprise continuous carbon (CC) and continuous glass sandwiching partial discontinuous carbon (DC). The model adopts the Hashin criterion for damage initiation in the fibers and the mixed-mode Benzeggagh-Kenane criterion on cohesive surfaces for delamination initiation and propagation. Numerically predicted stress–strain results are verified with experimental results under tensile loading. Results show pseudo-ductility increases with the increase in DC layers, and pseudo-yield strength and strain increase with the increase in CC layers. 3D-Digital Image Correlation results indicate delamination growth on pseudo-ductile laminates, and the calculated Poisson’s ratios show pseudo-ductility occurs below 0.27. Moreover, Poisson’s ratio decreases with an increase in pseudo-ductility.

Thin‐ply hybrid composite is an attractive technology for realizing high‐performance ductile composites (carbon and glass). However, the continuous carbon (CC) layers are limited to a thickness that can only emit small fracture energies to achieve pseudo‐ductility, compromising the mechanical performance of the laminates due to the low carbon/glass ratio. To solve this problem, four different lay‐up architectures of partially discontinuous carbon (DC) and angled carbon layers were coupled with continuous glass and carbon to increase the carbon/glass ratio maintaining pseudo‐ductility and improve mechanical properties. When under tensile loading, sandwiched DC layers with CC layers (H212) can achieve pseudo‐ductility with good mechanical properties compared to a sample with similar carbon layer thickness but with CC sandwiched by DC layers (H412). An improvement of 13% on the modulus and 2% on the yield strength is registered. Besides, acoustic emission (AE) analysis and sentry function are used to monitor the behavior of the respective damage mechanisms in the hybrid composites. The AE procedure used clustered the carbon and glass fiber breakages separately. Consequently, the sentry function analysis shows the damage mechanisms damage progression causing pseudo‐ductility.

The effects of hybridization on the flexural properties of interlayer and intralayer Carbon/Glass (C/G) composites were explored in this work. First, the theoretical analysis of stress distribution on interlayer hybrid composites was discussed. The experimental results showed that the layer structure is the critical factor affecting the flexural properties for interlayer hybrid composites, and the mixed ratio has no obvious impact. Since the carbon fiber is distributed at the top or bottom surface, the interlayer composites can obtain the maximum flexural modulus. Some structures can even achieve the same modulus as the pure carbon composites, and an excellent flexural strength can be attained with the carbon fiber located in the bottom layer. In terms of the intralayer hybrid composites, the fracture strain, flexural modulus, and flexural strength basically change linearly as the glass fiber content increases, which is consistent with the calculated values via the rule of mixture (ROM). Additionally, the C/G mixed ratio has a decisive effect on the flexural properties of intralayer hybrid composites; however, they are affected weakly by the layer structure. In general, some structures of the interlayer hybrid composites exhibit better flexural properties than that of the intralayer hybrid composites at the same C/G hybrid ratio; the alterations in layer structures make it possible to obtain excellent flexural properties for interlayer hybrid composites with less carbon fiber.