Abstract:The energy-absorbing behaviour of an aluminium honeycomb core reinforced with unidirectional and woven carbon fibre reinforced plastic composite tubes has been investigated experimentally at quasi-static rates of strain. Small diameter carbon fibre reinforced plastic tubes, with chamfered ends, were inserted into the cells of an aluminium honeycomb in order to yield a lightweight energy-absorbing material. The resulting data are compared with crushing tests on arrays of free-standing composite tubes, supported… Show more
“…These observations are in agreement with previous work on unidirectional and woven composite tubes. 25 Figure 8.Load–displacement graphs following crushing tests on the [0°, 90°] s , [0°,+45°, −45°, 0°] and [0°] 4 core structures.…”
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.
“…These observations are in agreement with previous work on unidirectional and woven composite tubes. 25 Figure 8.Load–displacement graphs following crushing tests on the [0°, 90°] s , [0°,+45°, −45°, 0°] and [0°] 4 core structures.…”
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.
“…Relatively, for HLS and HLM structures, the SEA value increase from 10.9 kJ/kg to 11.5 kJ/kg. However, the SEA values from single to multiple tube reinforced foam structure did not vary significantly due to the influence of the initial mass of the structure as it is inversely proportional to the SEA value, as proposed by Alantali et al [ 16 ]. Invariably, the bamboo structures always dominated in any cases.…”
In recent years, there has been a growing interest for composite materials due to the superior capability to absorb energy and lightweight factor. These properties are compatible to be utilized in the development for transportation system as it can reduce the fuel consumption and also minimize the effect of crash to the passenger. Therefore, the aim for this project is to study the compression strength and energy absorbing capability for Polyvinyl chloride (PVC) and bamboo tubes reinforced with foam. Several parameters are being considered, these being the effect of single and multiple tube reinforced foam structure, foam density, diameter of the tube as well as effect of different crosshead speed. The results showed that increasing the relative foam density will led to an increase in the compression strength and specific energy absorption (SEA) values. Furthermore, a significant increase of compression strength can be seen when several tubes are introduced into the foam while SEA remained almost the same. Finally, the influence of crosshead below 20 mm/min did not vary significantly for both compression strength and SEA.
“…Recently, there has been growing interest in the possibility of using energy-absorbing tubes as core materials in sandwich structures [27–30]. Xiang et al.…”
Section: Introductionmentioning
confidence: 99%
“…Alantali et al. [29] studied the effect of reinforcing an aluminium honeycomb core with small composite tubes on energy-absorption under quasi-static loading. Here, it was shown that a significant enhancement in SEA could be achieved by incorporating composite tubes into the honeycomb core.…”
The energy-absorbing response of sandwich structures with exceptionally high levels of energy absorption is investigated. The sandwich panels are produced by fixing small composite tubes onto metal facings with surface features that reflect the internal geometry of the tubing. Small diameter tubes are employed to manufacture the cores, since it is well established that the specific energy absorption (SEA) characteristics of a composite tube increase as the inner dimension (diameter or wall-to-wall) to thickness ratio decreases. Tests have been undertaken on tubular arrays based on both circular and square composite tubes. The effect of varying the areal density of the tubular array within the core was investigated by systematically increasing the number of tubes from one to nine. An examination of the composites during the crushing process indicated that all of the tubes failed in a splaying process, involving significant fracturing of fibers and longitudinal splitting. The measured values of SEA remained relatively constant in most cases as the areal density of the tubular arrangement was increased, suggesting that cores could readily be designed to absorb known levels of applied external energy. Arrays based on circular tubes offered higher energy-absorbing characteristics than their square counterparts, with values in excess of 100 kJ/kg being recorded in some cases. It is believed that these tubular sandwich structures offer potential for use in components that are subjected to extreme dynamic loading, such as those associated with impact and blast.
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