Search

Natural fibre waste is a material with high material resistance, including fibres derived from coconut fruit. Coconut fruit waste is frequently underutilised and can contribute to environmental pollution if not handled correctly. This study's objective is to convert waste from coconuts into fibres, incorporate them into composite mixtures, and produce robust materials. Using coconut fibre presents a significant advantage in that it is easily biodegradable, reducing environmental pollution. The aim of this research is to produce a composite board material using HDPE plastic and coconut fibre, which is resistant to corrosion, through the hot felting method. This method of producing composite materials results in minimal voids and high material density, effectively reducing the chances of material failure. The composite specimens were subjected to testing following the ASTM D 638-01 standard. Technical abbreviations used throughout the text will be explained upon first use. The study achieved an excellent average tensile strength, strain, and elastic modulus of 22.45 MPa, 7.15%, and 5.13 MPa, respectively. The manufacture of composite materials using coconut coir fibre combined with HDPE plastic through the hot felting method resulted in high material strength, corrosion resistance, and reprocessability.

This study successfully explored and evaluated the impact of notches modification in U, V, and square shapes on both tensile and shear strength using Arcan fixture. ASTM D 5379 was incorporated to evaluate the model then compared with FEA simulation. Composite material featuring a U-shaped notch possesses a notable advantage in terms of its tensile strength and shear strength values, which measure at 276.3 MPa and 14.9 MPa, respectively. 3D Hashin's damage model also employed to compare and validate the shear damage resulting from each notch of the experimental work. The composite with a U-shaped notch demonstrates excellent capacity for withstanding both tensile and shear loading without compromising its strength and fracture resistance in shear. the failure mode analysis was showed that the matrix failure tent to make weaker of the specimen, although the fiber still stands and kinked. The present study can be used as the leading method to evaluate the hybrid laminates applied in wind turbines, automotives body structures, and aircraft structures.

This paper presents research on the use of anisogrid lattice structures in fighter wing applications. While the anisogrid lattice structure has been widely used in spacecraft structures, its implementation in main aircraft structures is still limited. The study is aimed at investigating the feasibility of utilizing an anisogrid lattice structure in fighter wing design. The analysis and optimization focus on determining the optimal weight of the composite wing structure, considering static, buckling, and flutter failure constraints. Various lift distributions, including triangular, Schrenk, and constant, are applied to evaluate the structure’s response to static failure caused by aerodynamic loads. The anisogrid structure design incorporates inclined lattice elements between ribs and spars, with spar arrangement in the wing box featuring an anisogrid configuration. The anisogrid lattice structure is expected to produce higher bending and torsional stiffness compared to conventional orthogonal structures, producing better flutter and buckling characteristics. The optimized wing structure successfully meets static, buckling, and flutter load requirements at speeds below 500 m/s. The study showcases triangular, Schrenk, and constant load distributions resulting in half-wing masses of 504, 571, and 707 kg, respectively. The results show that flutter and buckling loads are no longer the critical loads in wing structural design but static load.

Exposure to unpleasant environmental conditions can lead to the degradation of polymer material. This study presents an experimental investigation of the long-term hydrothermal and physical ageing behaviour of bio-based photopolymer resin. Bio-based resin specimens were prepared using vat photopolymerization-based 3D printing and submersed in water at 28.5 °C (SW-28.5 °C), 50 °C (SW-50 °C) and 75 °C (SW-75 °C) for 90 days to evaluate the influence of moisture, temperature and ageing time on the characteristics of bio-based resin specimens. Several tests were performed, including moisture absorption, fourier transform infrared spectroscopy (FTIR), tensile, hardness and microstructural tests to determine the mechanical, chemical and microstructural characteristics of bio-based resin specimens. The result showed that moisture absorption of SW-75 °C specimens were far higher up to 3 times extra moisture content than dry-fresh (DA) specimens. A direct relationship between moisture absorption and reduction in tensile and hardness properties was observed, with the tensile strength and hardness of specimens decreased up to 55.6% and 7.8%, respectively, after submersion in water at 28.5 °C for 90 days. As expected, the bio-based resin specimens showed notable physical degradation after being submersed in water at 75 °C, indicated by a decrease in tensile strength up to 58.9% only after one day of submersion. Formation of cracks on the specimens was observed after submersion in water at 50 °C and 75 °C, which also contributes to a decrease in the mechanical properties of bio-based resin specimens. The FTIR analysis showed several absorption peaks were getting less visible after submersion in water at 75 °C, indicating the notable degradation of bio-based resin specimens. Accordingly, understanding the polymer degradation is very important in the context of design considerations and predicting the service life of polymeric components.

Due to their anisotropic behavior, composite structures are weak in transverse direction loading. produces transverse cracks, which for a laminated composite, may lead to delamination and total failure. The transition from transverse crack to delamination failure is important and the subject of recent studies. In this paper, a simulation of transverse crack and its transition to delamination on cross-ply laminate was studied extensively using a cohesive element Finite Element Method (FEM). A pre-cracked [0/90] composite laminate made of bamboo was modeled using ABAQUS/CAE. The specimen was in a three-point bending configuration. Cohesive elements were inserted in the middle of the 90° layer and in the interface between the 0° and 90° layer to simulate transverse crack propagation and its transition to delamination. A load–displacement graph was extracted from the simulation and analyzed. As the loading was given to the specimen, stress occurred in the laminates, concentrating near the pre-cracked region. When the stress reached the tensile transverse strength of the bamboo, transverse crack propagation initiated, indicated by the failure of transverse cohesive elements. The crack then propagated towards the interface of the [0/90] laminates. Soon after the crack reached the interface, delamination propagated along the interface, represented by the failure of the longitudinal cohesive elements. The result of the numerical study in the form of load–displacement graph shows a consistent pattern compared with the data found in the literature. The graph showed a linear path as the load increased and the crack propagated until a point where there was a load-drop in the graph, which showed that the crack was unstable and propagated quickly before it turned into delamination between the 0o and 90° plies.

This paper presents new insight on the potential of piezoaeroelastic energy harvesting on the transport aircraft wing structure. A novel numerical investigation is conducted in the present study. An advanced iterative finite element method (FEM) is applied to estimate the amount of harvested energy. Currently, FEM-based commercial software has a limited application on piezoelectric structures, i.e., actuator and sensor. The iterative FEM algorithm extends the commercial software implementation for the energy harvesting analysis. The multidisciplinary issue of the aeroelastic phenomenon and piezoelectric energy harvesting is evaluated in the present case. Likewise, interestingly, stress and failure analysis of a lifting surface with an active energy harvesting component could be enabled. Implementation of a wing with an embedded piezoelectric layer is concerned. A cruise flight condition and gust disturbance are evaluated. The analysis concerning the occurrence of gust also provides a more realistic insight into the power harvested during a flight operation.

Nowadays, the hybridization of natural and glass fiber has promised several advantages as a green composite. Nevertheless, their different characteristics lead to poor mechanical bonding. In this work, agel fiber and glass fiber was used as reinforcements, and activated carbon filler was added to the polymer matrix of a hybrid composite to modify its characteristics and mechanical properties. A tensile and bending test was conducted to evaluate the effect of three different weight percentages of activated carbon filler (1, 2, and 4 wt%). Vacuum-assisted resin infusion was used to manufacture the hybrid composite to obtain the high-quality composite. The results have revealed that adding 1 wt% filler yielded the most optimum result with the highest tensile strength, flexural strength, and elastic modulus, respectively: 112.90 MPa, 85.26 MPa, and 1.80 GPa. A higher weight percentage of activated carbon filler on the composite reduced its mechanical properties. The lowest test value was shown by the composite with 4 wt%. The micrograph observations have proven that the 4 wt% composite formed agglomeration filler that can induce stress concentration and reduce its mechanical performance. Adding 1 wt% filler offered the best dispersion in the matrix, which can enhance better load transfer capability.

Research on natural-fiber-reinforced polymer composite is continuously developing. Natural fibers from flora have received considerable attention from researchers because their use in biobased composites is safe and sustainable for the environment. Natural fibers that mixed with Carbon Fiber and or Glass Fiber are low-cost, lightweight, and biodegradable and have lower environmental influences than metal-based materials. This study highlights and comprehensively reviews the natural fibers utilized as reinforcements in polyester composites, including jute, bamboo, sisal, kenaf, flax, and banana. The properties of composite materials consisting of natural and synthetic fibers, such as tensile strength, flexural strength, fatigue, and hardness, are investigated in this study. This paper aims to summarize, classify, and collect studies related to the latest composite hybrid science consisting of natural and synthetic fibers and their applications. Furthermore, this paper includes but is not limited to preparation, mechanism, characterization, and evaluation of hybrid composite laminates in different methods and modes. In general, natural fiber composites produce a larger volume of composite, but their strength is weaker than GFRP/CFRP even with the same number of layers. The use of synthetic fibers combined with natural fibers can provide better strength of hybrid composite.