Strength Of Carbon Fiber Reinforced Composites Research Articles

Evaluation of new nano-cutting fluids for the processing of carbon fiber-reinforced composite materials

Carbon fiber-reinforced composites (CFRP), known for its impressive specific strength and modulus, finds extensive applications in defense, aerospace, automotive, and various other industries. Nevertheless, the widespread application of dry cutting in machining Carbon Fiber Reinforced Polymer (CFRP) presents significant challenges, including dust pollution, fiber layer delamination, and uneven surface quality. These issues make the machining of CFRP a formidable task. In the present investigation, a novel nanohybrid cutting fluid was successfully prepared by adding molybdenum disulfide (MoS2)/silicon carbide (SiC) nanoparticles to a base-cutting fluid synthesize from ethanol, polyethylene glycol, and sodium dodecyl sulfate. Moreover, employing minimal lubrication techniques, the nano-cutting fluid was applied to the milling process of CFRP. The feasibility of applying the cutting fluid to CFRP machining was demonstrated through short beam shear tests. Horizontal comparative milling tests were executed on CFRP, varying operational parameters and cooling-lubrication scenarios. The cooling-lubrication mechanisms of the nanofluid were analyzed, providing further validation of the effectiveness of the cutting fluid in CFRP machining. The results suggest that the nanofluid has a negligible impact on the interlaminar shear strength of CFRP, with only a 3.85% reduction. In comparison to other cooling-lubrication conditions, milling CFRP with the novel nanofluid resulted in a reduction of milling forces by 4.78%–24.84%, a decrease in milling temperatures by 15.38%–69.37%, a lowering of surface roughness by 10.78%–35.93%, and a reduction in tool tip wear by 6.25%–53.81%. Observable phenomena such as fiber pull-out and fracture were significantly reduced.

Solvent-induced micro-morphological structure strategy regulating the interfacial mechanism of carbon fiber reinforced composites

Current research on cellulose nanofiber (CNF) in the field of mechanical properties mainly involves the direct application of CNF and simple composites with other materials. The relationship between the morphology and structure of CNF-based materials and the target functions of composites has rarely been explored. Here, as an example of carbon fiber reinforced composites (CFRP), CNF-based organic coating with different micromorphological structures was fabricated on the surface of carbon fiber (CF) by regulating the solvent ratio of binary solvents (deionized water/ethanol). The trends of their chemical components and microstructures were investigated, as well as their effects on the interfacial bonding performance of CFRP. The results indicated that an increase in the ratio of deionized water in the binary solvent led to a smaller raised structure with poor adhesion and an increase in coating uniformity on the organic coating, which would directly affect the tensile strength (TS) of the CF and the interlaminar shear strength (ILSS) of CFRP. This research presents important insights into the mechanism of composite interfaces based on the differences in the micro-morphological structures of materials.

Aminated carbon nanotube enhanced composite T‐joints mediating CFRP load‐bearing capacity improvement

AbstractAdhesive bond is the weakest part of carbon fiber reinforced composites (CFRP) force‐bearing structure. Therefore, enhancing the strength of the adhesive bond is key to improve force‐bearing structure. In this study, adhesive strength of the common CFRP T‐joint was enhanced by aminated carbon nanotubes (CNT). To begin with, shear tensile strength of single‐lap‐joint laminated composites with various CNT content was verified, which peaked at 0.5 wt%. It was indicated that the adhesive bond of deltoid is the weakest area in a T‐joint. CNT was applied in the deltoid of composite T‐joint and pull‐off test was conducted to investigate the progress from the initiation and evolution of damage as well as the final failure. The aminated CNT employed in this study formed an effective load transmission through physical engagement and chemical bonding; the addition of 0.5 wt% CNT effectively enhanced tensile strength and toughness, improving mechanical property of the adhesive bond. This study provides a solution to enhance the adhesive area of CFRP load‐bearing structure with CNT, consequently improve the load‐bearing strength of composite.Highlights Aminated CNT is substantially improve the adhesive strength of CFRP T‐joint. Tensile strength and toughness of T‐joint deltoid was optimized by 0.5 wt% CNT. Effective load transmission through physical engagement and chemical bonding.

Comparative study of the effect of fiber surface treatments on the flexural and interlaminar shear strength of carbon fiber-reinforced composites

The aim of this study was to achieve enhanced flexure and interlaminar shear strength of carbon fiber-reinforced composites by grafting MWCNTs and depositing PyC layer on the fiber using CVD technique. The surface morphology of fiber prior and after treatment was examined by FESEM and TEM and the composites fabricated with surface modified fiber were tested by three-point bend test for comparative flexure and interlaminar shear behavior. A remarkable improvement of 32 % and 54 % was observed in the flexure strength of composites made of CNTs grafted and PyC-coated fiber respectively as compared to reference composites whereas significant augmentation of 35 % and 53 % respectively was found in the ILSS of composites. In-depth fractographic investigation was conducted to investigate the mechanisms responsible for this enhancement in flexure strength and ILSS of composites. The mechanical test results were supported and validated by the fractographic analysis. Individual CNT pullout, CNTs bundle pullout and crack bridging by CNTs were evidently observed as dominant mechanisms of fracture in these composites in addition to conventional interface debonding and fiber pullout.