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Delamination is one of the life‐limiting failure modes for fiber reinforced polymer (FRP) composite composites resulting in poor damage tolerance, as this failure mode occurs at considerably lower loads. Owing to the enormous demand and mass production of FRP composites, a large amount of fiber waste is produced worldwide. This triggers concern about utilizing these fiber wastes for some valuable applications. The present study aims to improve the overall damage tolerance of laminated glass/epoxy composites via the introduction of waste short carbon fibers (SCFs) reinforcement in the epoxy matrix. The effect of various SCF contents (0.1, 0.3, and 0.5 wt%) in glass fiber/epoxy composites were evaluated experimentally for their interlaminar fracture toughness in terms of both crack development and propagation under mode I and II interlaminar fracture toughness tests, at elevated temperatures (30, 50, and 70°C). Based on the experimental results, glass/epoxy composite with 0.1 wt% of SCF revealed 13.49% and 20.45% increment in mode I and II interlaminar fracture toughness, respectively, at ambient temperature. A positive reinforcement effect could be noticed for GIC and GIIC values up to 50°C. However, due to residual interfacial stresses, interfacial debonding, and epoxy softening, a negative reinforcement effect could be noticed at 70°C. Delamination initiation and crack propagation mechanisms have been explored at elevated temperatures. Fractographic studies have been carried out using a scanning electron microscope to identify the failure mechanisms. [ABSTRACT FROM AUTHOR]

An experimental study is performed to investigate the electro-mechanical response of three-dimensionally conductive multi-functional glass fiber/epoxy laminated composites under quasi-static tensile loading. To generate a threedimensional conductive network within the composites, multi-wall carbon nanotubes are embedded within the epoxy matrix and carbon fibers are reinforced between the glass fiber laminates using an electro-flocking technique. A combination of shear mixing and ultrasonication is employed to disperse carbon nanotubes inside the epoxy matrix. A vacuum infusion process is used to fabricate the laminated composites of two different carbon fiber lengths (150 mm and 350 mm) and four different carbon fiber densities (500, 1000, 1500, 2000 fibers/mm2). A four circumferential probe technique is employed to measure the in-situ electrical resistance of composites under tensile load. Although composites of both carbon fiber lengths showed significant decrease of sheet resistance under no mechanical load conditions, composites of 350 mm long carbon fibers showed the lowest resistivity of 10 X/sq. Unlike the resistance values, composites of 350 mm carbon fibers showed a significant decrease in Young's modulus compared to 150 mm counterparts. For the electro-mechanical response, composites containing carbon fibers of 150 mm long demonstrated a maximum value of percentage change in resistance. These results were then compared to both 350 mm and no added carbon fibers under quasi-static tensile loading. [ABSTRACT FROM AUTHOR]