The energy-absorbing characteristics of carbon fiber-reinforced epoxy honeycomb structures

Abstract

This paper investigates the compression properties and energy-absorbing characteristics of a carbon fiber-reinforced honeycomb structure manufactured using the vacuum-assisted resin transfer molding method (VARTM). The composite core materials were manufactured using a machined steel baseplate onto which hexagonal blocks were secured. A unidirectional carbon fiber fabric was inserted into the slots and the resulting mold was vacuum bagged and infused with a two-part epoxy resin. After curing, the hexagonal blocks were removed, leaving a well-defined composite honeycomb structure. Samples were then cut from the composite cores and inspected in an X-ray computed tomography machine prior to testing. Mechanical tests on the honeycomb structures yielded compression strengths of up to 35 MPa and specific energy absorption values in excess of 47 kJ/kg. When normalized by the density of the core, the resulting values of specific strength were significantly higher than those measured on traditional core materials. The unidirectional cores failed as a result of longitudinal splitting through the thickness of the core, whereas the multidirectional honeycombs failed in a combined splitting/fiber fracture mode, absorbing significantly more energy than their unidirectional counterparts. Increasing the weight fraction of fibers served to increase the strength and energy-absorbing capacity of the core. Finally, it was also shown that introducing a chamfer acted to reduce the initial peak force and precipitate a more stable mode of failure.

Progressive damage and failure modeling in composite cylindrical pyramidal lattice structure

“…As a result, studies on these structures have increased. Some studies have been considered two-dimensional topologies of isogrid, 10,11 anisogrid, 10,12,13 and honeycomb 4,14 cores as well as three-dimensional topologies of pyramidal, 6–8,15–20 tetrahedral, 21,22 kagome, 23 X-type, 24,25 octet-truss, 26,27 and corrugated 9,28 cores. Furthermore, the effect of using metal 7,27,29,30 and fiber-reinforced composite (FRC) materials 17–26 on the capability of carrying various loading has been investigated.…”

“…Such a core increases the strength and stiffness of sandwich structures without significantly changing their weight. 1–3 Absorption of energy 4–7 and vibration damping 8,9 is well carried out in these structures. Thus, sandwich structures have found many uses in the aviation, marine, and automobile industries.…”

Initial and progressive failure analysis of a composite pyramidal lattice cylinder under axial loading: A comparison with experimental results

“…Such a core increases the strength and stiffness of sandwich structures without significantly changing their weight. 1–3 Absorption of energy 4–7 and vibration damping 8,9 is well carried out in these structures. Thus, sandwich structures have found many uses in the aviation, marine and automobile industries.…”

“…As a result, studies on these structures have increased. Some studies have been considered two-dimensional topologies of isogrid, 10,11 anisogrid 10,12,13 and honeycomb 4,14 cores as well as three-dimensional topologies of pyramidal, 6–8,15–20 tetrahedral, 21,22 kagome, 23 X-type, 24,25 octet-truss 26,27 and corrugated 9,28 cores. Furthermore, the effect of using metal 5,7,27,29 and fiber reinforced composite (FRC) materials 17–26 on the capability of carrying various loading has been investigated.…”

“…Furthermore, the effect of using metal 5,7,27,29 and fiber reinforced composite (FRC) materials 17–26 on the capability of carrying various loading has been investigated. Examples of these loadings are axial compression, 10–13 in-plane compression, 17,19,25,28,29 and out-of-plane compression 4,16,21–25,27,29 loads as well as on three-point bending, 23,28 torsion, 18 shear loading, 16,21,25–29 and impact loading. 5–7,14 Researches have shown that the use of carbon-FRC in comparison with metal materials, in addition to improving the mechanical behavior of structures, can lead to high fuel efficiency in naval ships and submarine propellers.…”