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This study investigated the effects of carbon-aramid arrangement and strain rate on crush tube energy absorption. Round composite tubes, each consisting of three layers of fabric, were made using four different carbon-aramid hybridization schemes. Hand lay-up and compression bladder molding were used in the fabrication process. In two hybridization schemes, carbon-aramid fabrics were arranged to evaluate the effect of axially graded impedance relative to the tube impact end. Static crush and low-velocity impact (LVI) tests were conducted, and the force-displacement responses, energy absorption characteristics, and failure modes were compared. Test results revealed that energy absorption was 20% to 60% higher in the low-velocity impact test than in static crush, regardless of the hybridization schemes. In both tests, material arrangement played a surprisingly important role that was comparable to the tube carbon content in energy absorption. Maximum specific energy absorption of 26.21 kJ/kg was obtained in the hybridization scheme with the low impedance at the initiator end, with increasing impedance towards the impact end. This amount of specific energy absorption is almost equivalent to the other hybridization scheme that has twice the carbon fiber content. This scheme facilitated initial damage modes that favored progressive folding in the rest of the tube. This study presents the idea of enhancing the crashworthiness of crash boxes using axially graded impedance material arrangement. It is recommended that the idea be subjected to more testing for verification and potential commercialization. [ABSTRACT FROM AUTHOR]

Natural fibre as a reinforcing agent has been widely used in many industrial applications. Nevertheless, several factors need to be considered, such as the size and weight percentage of the fibre used in binding. Using fused deposition modelling (FDM), this factor was investigated by varying the size of natural fibre as the responding variable with a fixed weight percentage of kenaf fibre. The process of modifying the natural fibre in terms of size might increase the dispersion of kenaf fibre in the polymer matrix and increase the adhesion bonding between the fibre and matrix of composites, subsequently improving the interfacial bonding between these two phases. In this paper, the effect of fibre size was evaluated by performing the mechanical test, Scanning Electron Micrograph (SEM) to observe the morphology of the composites, and also by surface analysis. The surface roughness was visualised using a 3D profilometer and the figure was illustrated as colour shading in the image. The composite with fibre size ≤100 μm displayed better tensile and flexural strength, compared to other sizes. In conclusion, by reducing the size of the fibre, the composites could develop high strength performance for industrial applications. [ABSTRACT FROM AUTHOR]

Owing to the increasing demand for high performance and lightweight materials, fiber metal laminates (FMLs) have become the alternative materials to replace metallic alloys. When the environmental friendliness of the materials is taken into consideration, plant fibers have shown an excellent potential to be employed as the reinforcements in FMLs. This work describes the mechanical behavior of kenaf and pineapple leaf fibers (PALF) reinforced metal laminates with various fiber contents, ranging from 10 wt% to 50 wt%. Fiber metal laminates were formed through the coalescence of metallic skin layers with the composite as the core. The mechanical tests were then conducted to study the tensile, flexural and Charpy impact properties of the structures. From the findings, it was concluded that both the kenaf and PALF based FMLs showed the optimum mechanical properties when the fiber content was fixed at 30 wt%. In addition, PALF based FMLs had shown higher mechanical properties over kenaf based FMLs. At a fiber content of 30 wt%, the tensile and flexural strength of PALF based FMLs were respectively 6.18% and 3.44% higher than kenaf based FMLs. In terms of impact properties, the impact strength of PALF based FMLs was 5.06% and 40.73% higher than kenaf based FMLs in the flatwise and edgewise orientations. [ABSTRACT FROM AUTHOR]

Fibre metal laminates (FMLs) are the contemporary sandwich materials that have been employed in the aerospace industries. The commercially available synthetic fibre based FMLs have shown excellent fatigue, impact and specific properties over those of metallic alloys. In order to explore the potential of environmental friendly cellulosic based materials, this research work aims to characterise the mechanical properties of novel woven pineapple leaf fibre reinforced metal laminates which were prepared through the hot compression moulding technique. For the comparison purpose, the mechanical properties of woven pineapple leaf fabrics and pineapple leaf fibre reinforced composite laminates were determined as well. It was concluded that the pineapple leaf fibre reinforced metal laminates evidenced salient mechanical and specific properties over pineapple leaf fabrics and composites. The specific tensile strength of metal laminates was 230.87% and 62.21% higher than those of the pineapple leaf fabrics and composite laminates whereas the specific flexural strength of metal laminates was 174.91% higher than composite laminates. Besides that, metal laminates also showed an impact strength of 91.49 kJ/m2 which was 143.13% greater than that of the composite laminates. The results indeed showed that the pineapple based FMLs could be considered as the promising and sustainable sandwich materials in future structural applications. [ABSTRACT FROM AUTHOR]

Fibre metal laminates are advanced sandwich materials that offer various outstanding properties over conventional metallic alloys and composites. This research study intends to investigate the effects of weaving architectures and stacking configurations on the mechanical properties of fibre metal laminates based on kenaf/pineapple leaf fibre. Fibre metal laminates were fabricated through the hot moulding compression technique. Mechanical tests were performed on the kenaf/pineapple leaf fibre-based fibre metal laminates. In accordance with the findings obtained, hybridisation had led to the improvement in the mechanical properties of fibre metal laminates in comparison with [K/K/K] fibre metal laminates. Overall, twill woven-ply [P/P/P] fibre metal laminates showed the highest tensile and flexural strength, which was 14.53% and 33.50% higher than twill woven-ply [K/K/K] fibre metal laminates, respectively. Besides, the twill woven-ply [P/P/P] fibre metal laminates also displayed the highest impact strength and indentation properties compared to other non-hybrid and hybrid fibre metal laminates. When comparing the fibre metal laminates with different weaving architectures, twill woven-ply fibre metal laminates were shown to have higher mechanical properties over those of plain woven-ply fibre metal laminates. [ABSTRACT FROM AUTHOR]

The use of polymer-based composites has been gaining popularity in the industry over the last few decades. Their high strength to weight ratio and high fatigue resistance make these composites the preferred materials for a wide variety of applications. The current trend has inclined towards hybrid fibre reinforced composites owing to their outstanding characteristics compared to non-hybrid composites. Numerous research works have been conducted to study the fatigue life behaviour of such composite materials. This study addressed the monotonic and dynamic performance of non-hybrid and hybrid natural fibre based composite materials, and the factors that influence their fatigue performance, along with the stiffness decay of each composite material. Most studies have shown the superior potential of using natural fibres in place of synthetic fibres in those critical applications that involve tensile and cyclic loading. [ABSTRACT FROM AUTHOR]

Fibre reinforced polymers are the contemporary advanced materials that possess high specific properties when compared to metallic alloys. They have been widely explored since the past few decades. This research study intends to investigate the quasi-static indentation behaviour of nonhybrid and hybrid pineapple leaf / Kevlar fibre reinforced composites with various stacking configurations. Four fibre stacking configurations were fixed in the composite laminates. The composite panels were fabricated through hot moulding compression process. Quasi-static tensile and indentation test were then conducted to measure the tensile properties, energy absorption, maximum indentation force and specific energy absorption of the non-hybrid and hybrid composites. The front and rear fracture surface of the non-hybrid and hybrid composites were analysed after the indentation test. The findings evidenced that the hybrid pineapple leaf / Kevlar fibre reinforced composites showed a positive hybrid effect where the tensile properties, maximum indentation force and energy absorption were drastically improved after partial incorporation of Kevlar fibre in the composites. However, the hybrid composites with the outermost Kevlar fibre and middle pineapple leaf fibre showed comparable tensile and indentation properties to the non-hybrid Kevlar fibre reinforced composites. The results demonstrated the high potential of hybrid pineapple leaf / Kevlar fibre reinforced composites in the replacement of non-hybrid Kevlar fibre reinforced composites. [ABSTRACT FROM AUTHOR]

Composite materials have gained wide acceptance among industries since the past decades. They have been widely employed in a wide variety of engineering applications. In this research, the influences of fibre stacking configurations on the indentation behaviour of pineapple leaf/glass fibres reinforced polypropylene hybrid composites were investigated. The indentation behaviours of hybrid composites were then compared to non-hybrid composites. Composites were fabricated through the hot press moulding compression technique using hydraulic hot press machine. The indentation behaviours of composites were presented in terms of maximum indentation force, energy absorption and specific energy absorption. The damage mechanism of composites was also studied after the indentation test. From the findings, it was concluded that the partial incorporation of glass fibre in the composite laminates improved the indentation resistance and energy absorption. In overall, nonhybrid glass fibre reinforced composite laminates showed the highest indentation resistance and energy absorption. However, the hybrid composites with the substitution of middle glass fibre with pineapple leaf fibre had a comparable indentation resistance and energy absorption to the non-hybrid glass fibre based composites. Therefore, these results have evidenced the potential of hybrid composites to supersede non-hybrid glass fibre based composites. [ABSTRACT FROM AUTHOR]

Use of fibre metal laminates (FML) in military cargo aircrafts improves impact and fatigue resistance and decreases weight. Such aircraft assembly largely requires secondary processing, and the machining of hybrid materials such as FML is a great challenge. In particular, drilling causes harsh delamination due to severe vibrations during machining. This work investigates the effect of traverse speed on delamination applied to abrasive water-jet machining. The hybrid laminate, an alternate stacking of AA 7475 and E-glass fibre/epoxy laminas, is produced by compression moulding. Drilling was carried out using constant jet pressure and stand-of distance, with variable traverse speed (10, 20 and 30 mm/min). Delamination is evaluated through optical microscopy based on the internal damage caused around the edges. Three delamination models are analysed to assess the structural integrity of the FML. Traverse speed, variation in hardness between metal and composite, and their positioning affected the kerf taper in the machined volume. Electron microscopy revealed the mechanism behind material erosion and production of kerf taper, for the lower traverse speed produced less kerf taper and dimensional deviation but higher fibre fraying and delamination occurred. [ABSTRACT FROM AUTHOR]

The use of natural fibre reinforced polymer composite in fibre metal laminate (FML) is the current interest. The potential and performance of FML based on natural fibre have been investigated. This paper investigated the effect of different stacking configurations (2/1, 3/2 & 4/3) subjected to quasi-static indentation test for oil palm empty fruit bunch fibre metal laminates (OPFML). This study used aluminium 6061 as a laminate skin and oil palm empty fruit bunch fibre reinforced polypropylene composites as a laminate layer. A motorised hydraulic moulding test press machine was used in this study to bond the FML panels at 155 °C, 1 kg/cm? and 4 min and for composites fabrication at 185°C, 35 kg/cm² and 8 min. Experiments were performed using a 12mm diameter hemispherical indenter with a constant strain rate of 1.0 mm/s. The indentation behaviour of OPFML panels were presented based on the peak load, maximum displacement, energy absorption and specific energy absorption (SEA) values. The results show that the highest stacking configuration, OPFML 4/3 has the highest value of the peak load, energy absorption and specific energy absorption due to the stiffer behaviour. From this study, it is found that the failure mode of quasi- static indentation test showed the damaged on aluminium and composite layers. Therefore, this study concludes that the stacking configuration influenced the indentation behaviour of OPFML panels. [ABSTRACT FROM AUTHOR]

Hybrid composites consist of two or more different fibres in a single matrix has become an interesting topic in the field of fibre reinforced polymers. In this study, woven kenaf and Kevlar fibre along with polypropylene were used to fabricate hybrid composites. Different fibre configurations of composite laminate materials were introduced to study its effects on the tensile, quasi-static indentation and lowvelocity impact characteristics of hybrid and non-hybrid composite materials. The composites were fabricated through a hot press compression moulding process. From the results, it was noticed that the hybrid kenaf / Kevlar fibre reinforced polypropylene composites showed a positive hybrid effect in which they demonstrated higher tensile and penetration resistance, compared to the non-hybrid kenaf fibre reinforced composites. Furthermore, partial incorporation of Kevlar fibre in the non-hybrid kenaf reinforced polypropylene composites also improved the low-velocity impact resistance of such materials. The findings revealed that a balance between the mechanical strength and the environmental friendliness could be achieved through hybridisation. [ABSTRACT FROM AUTHOR]

Fibre Metal Laminate (FML) is hybrid material that has the combined advantages of metallic materials and fibre reinforced matrix. It has been widely used in the aircraft industry for impact prone applications due to its excellent fatigue and impact resistance. This research focuses on the quasi-static indentation behaviour of fibre metal laminates based on NaOH treated and untreated kenaf bast fibre with fibre loading wt% of 50, 60 and 70 and fibre length in cm of 3, 6 and 9. Aluminium 5052-O has been used as the skin layers of FML in this study. Hot compression moulding method has been used to fabricate the composite and FML panels for this study. The prepared specimens were tested in accordance with ASTM D 6264 using Instron 5585 universal testing machine to assess their quasi-static indentation performance. The results revealed that treated FMLT-60(9) with fibre loading 60wt% and fibre length of 9cm exhibited the highest energy absorption at 30.82 J. [ABSTRACT FROM AUTHOR]