Manufacturing and Performance Evaluation of Carbon Fiber–Reinforced Honeycombs

• Main Authors: Sanjeev Rao, Jimmy Thomas, Alia Aziz, Wesley Cantwell
• Format: Article
• Language: English
• Published: MDPI AG 2019-01-01
• Series: Journal of Composites Science
• Subjects: honeycombs; carbon fiber; slit tape; fiber-reinforced cores
• Online Access: https://www.mdpi.com/2504-477X/3/1/13

In this work, the manufacturing characteristics and a performance evaluation of carbon fiber&#8315;reinforced epoxy honeycombs are reported. The vacuum-assisted resin transfer molding process, using a central injection point, is used to infuse a unidirectional dry slit tape with the epoxy resin system Prime 20 LV in a wax mold. The compression behavior of the manufactured honeycomb structure was evaluated by subjecting samples to quasi-static compression loading. Failure criteria for the reinforced honeycombs were developed and failure maps were constructed. These maps can be used to evaluate the reliability of the core for a prescribed loading condition. Improvements in the load-carrying capacity for the reinforced samples, as compared with unreinforced specimens, are discussed and the theoretical predictions are compared with the experimental data. The compression test results highlight a load-carrying capacity up to 26 kN (~143 MPa) for a single hexagonal cell (unit cell) and 160 kN (~170 MPa) for cores consisting of 2.5 &#215; 3.5 cells. The failure map indicates buckling to be the predominant mode of failure at low relative densities, shifting to cell wall fracture at relative densities closer to a value of 10^&#8722;1. The resulting energy absorption diagram shows a monotonic increase in energy absorption with the increasing <i>t/l</i> ratio of the honeycomb core cell walls.