ORCID Profile
0000-0001-5840-4356
Current Organisation
Khalifa University of Science and Technology
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Publisher: SAGE Publications
Date: 25-11-2021
Abstract: In this research, an experimental investigation of the microstructural, viscoelastic, and flexural properties of glass/carbon hybrid Fiber Reinforced Polymer (FRP) composites consisting of two different types of weaves (plain and twill) was carried out. The hybrid composites were manufactured by using the VARTM technique. The scanning electron micrographs showed that the hybridization resulted in a significant improvement in fiber-matrix adhesion of the hybrid composites compared to the pure glass fiber reinforced polymer (GFRP) composites based on plain weave glass fabrics, whereas the best fiber-matrix adhesion was observed in carbon fiber reinforced polymer (CFRP) composites. The synergistic effect due to hybridization lead to substantial improvements in the dynamic mechanical and flexural response of the manufactured composites. The hybrid composites exhibited a 149% increase in flexural strength, and a 144% increase in the flexural modulus compared to the GFRP composites, and an increase of 109% in the average value of the storage modulus at three different frequencies (1 Hz, 5 Hz and 10 Hz) compared to the GFRP composites. Whereas, the highest values were observed for pure CFRP composites for both flexural strength and modulus. A positive hybridization effect was also confirmed by the higher experimental values compared to the estimated results calculated by using the Rule of hybrid mixtures (RoHM). Due to higher fiber volume content, the GFRP exhibited the highest thermal stability compared to other specimens.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 27-03-2023
DOI: 10.1038/S41598-023-31672-Y
Abstract: One of the potential applications of 2D materials is to enhance multi-functionality of structures and components used in aerospace, automotive, civil and defense industries. These multi-functional attributes include sensing, energy storage, EMI shielding and property enhancement. In this article, we have explored the potential of using graphene and its variants as data generating sensory elements in Industry 4.0. We have presented a complete roadmap to cover three emerging technologies i.e. advance materials, artificial intelligence and block-chain technology. The utility of 2D materials such as graphene nanoparticles is yet to be explored as an interface for digitalization of a modern smart factory i.e. “factory-of-the-future”. In this article, we have explored how 2D material enhanced composites can act as an interface between physical and cyber spaces. An overview of employing graphene-based smart embedded sensors at various stages of composites manufacturing processes and their application in real-time structural health monitoring is presented. The technical challenges associated with interfacing graphene-based sensing networks with digital space are discussed. Additionally, an overview of the integration of associated tools such as artificial intelligence, machine learning and block-chain technology with graphene-based devices and structures is also presented.
Publisher: SAGE Publications
Date: 08-12-2022
DOI: 10.1177/08927057221145551
Abstract: In this study, carbon fiber/Elium ® composites are manufactured using the resin infusion manufacturing technique. Artificial cracks representing impact-induced delamination are incorporated during layup. The laminates are subsequently healed using several healing parameters. The bonding mechanisms are investigated through microscopic analyses and X-ray Computed Tomography (XCT). The mechanical performance of the healed composites is investigated through four-point bending tests. It is found that as the healing temperature is increased, the cracks are gradually healed by interdiffusion and macroscopic resin flow across each crack interface. The 3D models generated from XCT images show an increase in solid volume fraction from 48% to 70% at the optimum healing parameters. The flexural strength and flexural modulus of the undamaged composites subjected to optimized healing condition are significantly increased relative to the room temperature cured pristine s les. The residual flexural strength of the damaged s les healed at the optimum parameters is 96% of the reference condition. The SEM images confirm that delamination from the previously-healed crack interfaces is the most dominant failure mode in the healed s les, in contrast to fiber fracture and brittle failure in the undamaged reference composite s les. The results show that the damaged composite laminates can be effectively healed and repaired to as good as undamaged laminates using the interdiffusion mechanism.
Publisher: SAGE Publications
Date: 06-04-2023
DOI: 10.1177/00219983231168791
Abstract: The effective design of channels in dry tape preforms is crucial for achieving desired preform permeability for successful resin injection for composites manufacturing using Automated Fiber Placement (AFP) process. Achieving target gaps and their locations in the AFP layup is extremely challenging. This work investigates the correlation between the spatial variability of the preforms and the in-plane permeability using an X-ray Computed Tomography (XCT) based characterization framework. The tomographic images of two different dry carbon tape preforms with different tape widths were used to generate realistic and XCT based stochastic models to be used for numerical permeability predictions. The variability in the tape placement by the robotic head and its effect on preform permeability was also examined through stochastic geometric modeling of the laid preform. A benchmark transient permeability measurement set-up was utilized to obtain experimental in-plane preform permeability through 2D radial mold filling. The in-plane numerical permeability values showed significant scatter, with a coefficient of variance of 75%–130%, which deviated from the experimental measurements by approximately one order of magnitude. These findings strongly re-affirm that the experimental permeability measurement technique based on transient mold filling of dry fiber AFP preforms is complex however, the XCT based stochastic modeling technique is an effective way to estimate the permeability of dry fiber AFP preforms virtually.
Publisher: SAGE Publications
Date: 07-10-2023
DOI: 10.1177/08927057211051773
Abstract: In this work, the long-term creep response of high-performance carbon fiber PEKK (CF/PEKK) composites was evaluated by performing extrapolated short-term flexural creep tests at various temperatures. The time-temperature superposition principle (TTSP) with vertical as well as horizontal shifting was used to generate master curves at reference temperatures of 120°C. Satin weave-based CF/PEKK prepregs were used to manufacture eight-layer composites via compression molding, with three different stacking sequences: (a) zero-direction [0] 8 (b) cross-ply [0, 90] 4 and (c) quasi-isotropic [90, −45, 45, 0] 2 s . The flexural properties under three-point bending arrangement in a universal testing machine were also evaluated. A dynamic mechanical thermal analyzer (DMTA) in three-point bending mode was used to evaluate the temperature-dependent viscoelastic properties of the three types of composites. The creep and creep-recovery behavior was evaluated at 40°C, 80°C, 120°C, 160°C and 200°C. To construct a master curve, extrapolated short-term isothermal creep tests were performed from 120°C to 180°C at the intervals of 10°C. The predicted master curve represents the creep behavior of composites over more than 10 years. It was shown that the quasi-isotropic CF/PEKK composites exhibited 27% and 12% higher creep resistance at 120°C as compared to zero-direction and cross-ply laminates, respectively. Higher flexural modulus (23%) and flexural strengths (33%) were also exhibited by the quasi-isotropic CF/PEKK composites. The final thickness of quasi-isotropic laminates was 8% lower than the 0 o laminates. After analyzing the cross-sections of the composites, it was proposed that the superior mechanical properties of the quasi-isotropic laminates could be due to enhanced nesting between neighboring prepreg layers during the compression molding process, which resulted in closer packing of the fibers. It has been shown that the prepreg stacking sequence could affect the creep behavior and flexural properties of the compression-molded CF/PEKK composites.
Publisher: SAGE Publications
Date: 03-2022
DOI: 10.1177/00219983221073985
Abstract: In this study, carbon fiber/thermoplastic (Elium ® ) honeycombs were manufactured using the resin infusion process in a customized metallic mold. Honeycomb cores, based on different carbon fiber layers, were manufactured to achieve four different fiber weight fraction composites. Two different types of specimens, based on a single honeycomb cell and five honeycomb cells, were prepared and subjected to compression loading. The results of these tests were compared with data from similar honeycomb structures based on carbon fiber–reinforced epoxy composite. It has been shown that the compressive strength and the specific energy absorption capacity of the honeycombs increase rapidly with increasing fiber weight fraction. The specific energy absorption capability of the novel thermoplastic honeycomb structures has been shown to be as high as 50 kJ/kg which compares favorably with other energy-absorbing core materials. The thermoplastic honeycomb specimens exhibited a similar specific energy absorption capability and an improved compressive strength compared to their epoxy counterparts. Furthermore, the CF/thermoplastic honeycombs exhibited enhanced structural stability and displayed a more uniform and progressive core failure mode than the longitudinal splitting observed in the CF/epoxy honeycombs. The honeycomb core that exhibited the best performance was then used to manufacture thermoplastic sandwich specimens based on CF/thermoplastic face sheets. Three point bend tests were conducted to determine the flexural strength of the sandwich s les and to identify the failure modes. Optical micrographs revealed that the flexural damage was primarily due to the core crushing and adhesive failure between the core and the composite skins.
Publisher: MDPI AG
Date: 10-03-2023
Abstract: In this study, two types of carbon-fiber-reinforced plastic (CFRP) composite scarf geometries were created using two scarf angles, i.e., 1.43° and 5.71°. The scarf joints were adhesively bonded using a novel liquid thermoplastic resin at two different temperatures. The performance of the repaired laminates was compared with pristine s les in terms of residual flexural strength using four-point bending tests. The repair quality of the laminates was examined by optical micrographs, and the failure modes after flexural tests were analyzed using a scanning electron microscope. The thermal stability of the resin was evaluated by thermogravimetric analysis (TGA), whereas the stiffness of the pristine s les was determined using dynamic mechanical analysis (DMA). The results showed that the laminates were not fully repaired under ambient conditions, and the highest recovery strength at room temperature was only 57% of the total strength exhibited by pristine laminates. Increasing the bonding temperature to an optimal repair temperature of 210 °C resulted in a significant improvement in the recovery strength. The best results were achieved for laminates with a higher scarf angle (5.71°). The highest residual flexural strength was recorded as 97% that of the pristine s le repaired at 210 °C with a scarf angle of 5.71°. The SEM micrographs showed that all the repaired s les exhibited delamination as the dominant failure mode, whereas the pristine s les exhibited dominant fiber fracture and fiber pullout failure modes. The residual strength recovered using liquid thermoplastic resin was found to be much higher than that reported for conventional epoxy adhesives.
Publisher: Informa UK Limited
Date: 05-02-2022
Publisher: Elsevier BV
Date: 02-2023
Publisher: Wiley
Date: 16-03-2022
DOI: 10.1002/PC.26587
Abstract: In this study, an online process monitoring system based on rGO coated glass fabric sensors was developed to monitor different stages of the resin infusion process. The developed sensors were able to monitor reinforcement compaction response, resin flow, race tracking, and resin cure when using thermoset resin and a novel low viscosity thermoplastic resin (i.e., Elium®). The coated glass fabric patches and strips were embedded at different locations within the laminate. The electrical resistance changes occurring within the embedded sensors during different stages of the manufacturing process were continuously monitored. The relative drop in overall resistance of the sensors upon contact with the resin systems was different for epoxy resin and Elium® resin due to differences in their electrical conductivity. It was found that the coating quality, dimensions, and spatial position of the sensors within the laminate and the type of resin system affected the performance of the sensors.
Publisher: Wiley
Date: 15-12-2023
DOI: 10.1002/PC.27210
Abstract: In this study, two different type of glass and carbon fiber hybrid laminates were manufactured using a low‐viscosity thermoplastic resin that is, Elium®. A detailed microstructure visualization study was conducted using X‐ray computed tomography (XCT) analysis. The viscoelastic properties were examined through dynamic mechanical analysis. The mechanical performance was investigated through flexural and tensile tests along with a fractographic study using optical and scanning electron microscopy. The XCT analysis revealed a weak interface between the Elium® resin and the glass fabric, with glass fiber specimens exhibiting a void content of 1.24%, in contrast to the carbon fiber specimens which showed void content of only 0.28%. Therefore, adding glass fabric layers in the hybrid laminates increased the void content, which had a negative impact on the overall mechanical performance. The average flexural strength of the hybrid specimen having G 2 C 4 G 2 stacking sequence was observed to be 254% higher than pure GFRPC specimens. Similarly, the tensile strength and Young's modulus of the same hybrid specimen showed 155% and 380% increases, respectively, compared to the GFRPC specimens. This increase was primarily due to higher stiffness of the carbon fibers and their better fiber – matrix interface. Whereas the tensile strain of the hybrid specimen having G 3 C 2 G 3 stacking sequence was 37% higher than that of the CFRPC specimens. The SEM images highlighted fiber fracture and brittle failure modes in the carbon fiber specimens, in contrast to fiber pullout, interfacial failure, poor fiber‐matrix bonding and ductile failure modes in the glass fiber specimens.
Location: United Arab Emirates
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