Mechanical Characteristics and Adhesion of Glass-Kevlar Hybrid Composites by Applying Different Ratios of Epoxy in Lamination

Abstract

Hybrid composites have great potential for specific strength and specific stiffness, effective in aerospace industries, submarines, and light-weight automotives. The mechanical strength and adhesiveness of hybrid laminates can be enhanced by effective use of matrix materials in different ratios of epoxy resin and epoxy hardener. Gentle use of resin and hardener in the fabrication of hybrid composites can alter tensile modulus, the bonding strength between matrix and fabric. Spectacular progress has been achieved by the selection of appropriate amounts of resin and hardener in the hybridization of composite laminate. Hybridization was made by Kevlar inorganic/organic fabrics and glass fabrics stacked with epoxy matrix material. To achieve the combination of mechanical properties and bonding strength, transparent epoxy resin and hardener of commercial grades mixed in various ratios are incorporated as matrix material to fabricate laminate. Three different sheets, named A (3:2), B (4:1), and C (2:3), were embedded by the hand layup method to prepare a hybrid composite. Experimental tests, according to ASTM 3039, were performed to determine the tensile mechanical properties. Peel tests, according to ASTM 6862-11, were performed to investigate the interlaminar strength between Kevlar and glass layers. Shore A and Shore C hardness durometers were used to find out the hardness of the specimens at different spots using the ASTM D-2240 standard. Finally, physical testing, such as density and then water absorption, was carried out using the ASTM D-570 standard to check the swelling ratio of the different specimens. The results obtained highlight that the specimen of the glass/Kevlar hybrid embedded in the ratio 3:2 in lamination has the best mechanical properties (tensile strength and hardness) and the lowest swelling ratio, while the material system in the ratio 4:1 shows the best interlaminar properties and adhesion capabilities.

Effect of seawater aging on the erosive wear response of aramid fiber reinforced composites

“…Figure 3 shows the particle size distribution that was obtained using a stereo microscope Olympus model SZ61 and approximately 550 measurements of sand grains were achieved. The laminated composites were obtained through the vacuum-assisted resin infusion manufacturing process, 12,21,26,27 using a proportion of 50% fiber and 50% resin in weight. For this, first the mold is cleaned and prepared by applying release grease, then the arrangement of fibers is placed, as shown in Figure 1, the non-stick fabric is placed on top of the arrangement, the distribution mesh and the feeder tubes of resin inlet and outlet are placed, everything is covered with the vacuum bag and the edge of the plate is sealed with polyurethane tape and the entire system is sealed, once an adequate seal is obtained, vacuum pressure of the order of 750 mm of Hg is applied, ensuring that there were no leaks in the system.…”

“…Figure7shows the average and dispersion of values of the roughness measurements (Ra). It can be seen that the aged samples exhibit a greater roughness in the surface reinforced with Kevlar fibers, in relation to the values of unaged samples, due to the superficial alteration of the composite specimen caused by seawater,21 as well as plasticization and swelling of the matrix.Figure8presents the results of the measurement of the average hardness. The average results obtained on all aged and unaged samples are very similar in the range of 88.225 to 89.138 Shore D. The highest hardness was exhibited by the U-GFRP samples, while the A-HFRP sample…”

“…19 Similarly, Tual et al 20 in evaluating the mechanical behavior of composite materials reinforced with Kevlar fabric and hybrid fabrics (glass fibers and Kevlar fibers), demonstrated that composites with a hybrid structure exhibited greater values in flexural resistance and impact energy absorption compared to composites reinforced only with Kevlar. Hussian Siyah et al 21 in studies on the mechanical and adhesion characteristics of fiberglass/Kevlar hybrid composites in different proportions of epoxy resin, found that the proportion of resin and hardener has a profound importance on both mechanical and physical properties. In the results reported by Dávila et al 22 in the microstructural characterization of materials composite of glass fibers, carbon and Kevlar, obtained by the vacuum-assisted resin infusion process, showed minimal amounts of air inclusions (pores) and delamination.…”

Study on Adhesion Reliability and Particle Inhibition of Epoxy Resin Coating in DC GIL after Thermal Ageing Experiment

“…Mini-sprinkles are small sized static sprinklers having a flow varying be-68 tween 150 and 300 liters per hour with a pressure of 1,5 bars [15] inducing water cooling 69 canopy [16]. Notably, the adoption of micro-irrigation in potato cultivation can result in 70 irrigation water savings of up to 40% [17], [18], energy savings as well as increased crop 71 quality and yields [19], [20]. The metal particles are aluminum spheres with a radius of 0.3 mm (ρ = 2.7 g/cm 3 ).…”

“…Polyethylene terephthalate (PET) film, insulating paint and epoxy resin are common coating materials in GIL [15]. Epoxy resin is widely used in engineering practice due to its good insulation performance, mechanical properties, excellent substrate adhesion and film-forming performance [16][17][18][19][20]. Coating the electrode with epoxy resin can effectively weaken the conduction of surface charge, change the electric field between the electrodes and inhibit the activity of particles.…”