Now showing 1 - 10 of 16
  • Publication
    An investigation of the processability of natural fibre reinforced polymer composites on shallow and flat thin-walled parts by injection moulding process
    ( 2013) ;
    S.M. Sapuan
    ;
    S. Sulaiman
    ;
    E.S. Zainudin
    ;
    K. Abdan
    Currently, many industries are trending towards producing products exhibit such properties as small thickness, lightweight, small dimensions, and environmental friendliness. In this project, flat or shallow thin-walled parts were designed to compare the advantages and disadvantages of lignocellulosic polymer composites (PP + 50 wt% wood) in terms of processability. This study focused on the filling, in-cavity residual stresses and warpage parameters associated with both types of thin-walled moulded parts. Thin-walled parts 0.7 mm in thickness were suitably moulded using lignocellulosic composite materials to determine the effects of filling. The analysis showed, the shallow thin-walled part is preferable in moulding lignocellulosic polymer composite material due to the low residual stress and warpage measured. The results also indicate that the shallow thin-walled part is structurally rigid, such that it can be used in applications involving small shell parts, and can be processed more economically using less material than the flat thin-walled part.
  • Publication
    Investigation on the Effect of Printing Parameters on Flexural properties of 3D Printed Polymeric Scaffolds
    ( 2022-01-24)
    Nur Syahirah Mohd Tamizi
    ;
    ; ;
    Basri A.A.
    Thermoplastic polymers (PLA) are used for bone scaffold reconstruction that helps facilitate the transportation of oxygen and nutrients, including cell activity such as migration, proliferation, attachment, and differentiation. Throughout evaluation of polymer scaffold of its mechanical properties that could heal human body injuries after implantation. However, these ideal parameters for polymeric scaffolds in terms of flexural characteristics are undefined in tissue engineering applications. The Taguchi approach was employed using an orthogonal array L9 to study the ideal print parameters for 3D printing and the elements that most influence flexural qualities, as well as to forecast the highest flexural strength that could be reached with the optimal printing parameter. Furthermore, the flexural test is an appropriate test to evaluate the mechanical properties of the scaffold. The Taguchi technique determined that a printing speed of 90 mm/s, a layer height of 0.2 mm, and a density of 60% infill was the optimal combination of parameters. Besides, Printing speed showed as the most significant factor contribution while the infill density is the lowest contributor. The maximum level of printing speed, the average percentage of infill, and the medium layer height are the best parameter combinations. Parameter optimization on the most influential contributor indicates the printing speed of the specimen. Thus, the parameter for the selected factor in scaffold fabrication was optimized with a significant contribution. The predicted flexural strength was 383.92 MPa, while actual test obtained was 360.221 MPa with an error of 6.57 %.
  • Publication
    Effects of different stress ratios on fatigue crack growth of rice husk fibre-reinforced composite
    ( 2020-08-01)
    Mohamed S.A.N.
    ;
    Zainudin E.S.
    ;
    Sapuan S.M.
    ;
    ;
    Arifin A.M.T.
    Polymers and polymer composites are susceptible to premature failure due to formation of cracks and microcracks throughout their service. Evolution of cracks and microcracks induces catastrophic material failure. Hence, detection/diagnostics, as well as effective repair of cracks and microcracks, is essential to ascertain performance reliability, cost efficiency, and safety for polymer structures. Upon adopting the Paris relation for empirical data, this study incorporated a mathematical model after weighing in cracks initiation and propagation in rice husk (RH) polymer structures, along with the several viable techniques for life prediction and fracture observation. The specimens contained 35% RH fibres and were produced via an injection molding process. Fatigue cracks were evaluated for stresses between 80 and 90% from ultimate tensile strength (UTS) for R = 0.1, 0.3, and 0.5. The outcomes signified that the increment in R value enhanced the growth rate of the crack. Upon elaborating the fracture analysis, this study discusses in detail both fracture mechanics and formation.
  • Publication
    Effects of ply orientations and stacking sequences on impact response of Pineapple Leaf Fibre (PALF)/Carbon hybrid laminate composites
    This study investigated the impact response behaviours of pineapple leaf fibre (PALF)/carbon hybrid laminate composites for different ply orientations and stacking sequences. The laminates were manufactured using a vacuum infusion approach with various stacking sequences and ply orientations classified as symmetric quasi-isotropic, angle-ply symmetric, and cross-ply symmetric. The laminates were analysed using an IMATEK IM10 drop weight impact tester with an increment of 5 J until the samples were perforated. This investigation reveals that the overall impact properties of PALF and carbon as reinforcements were improved by a beneficial hybridised effect. The laminates with an exterior carbon layer can withstand high impact energy levels up to 27.5 J. The laminate with different stacking sequences had a lower energy transfer rate and ruptured at higher impact energy. The laminates with ply orientations of [0°/90°] and [±45°]8 exhibited 10% to 30% better energy absorption than those with ply orientations of [±45°2, 0°/90°2]s and [0°/90°2, ±45°2]s due to energy being readily transferred within the same linear ply orientation. Through visual inspection, delamination was observed to occur at the interfaces of different stacking sequences and ply orientations.
      6  13
  • Publication
    Effect of varying core density and material on the quasi-static behaviors of sandwich structure with 3D-printed hexagonal honeycomb core
    Additive manufacturing (AM) involves the development of complex, lightweight sandwich structures for the automotive and aerospace industries. These structures are essential for load bearing and impact resistance. Nevertheless, there is a significant obstacle of failure under compressive loading, e.g. through brittle fractures and crushing. To address this issue, this study evaluates the compressive properties, energy absorption and failure damage in quasi-static tests (flatwise, in-plane, and flexural) of sandwich composites with 3D-printed hexagonal honeycomb cores of different unit cells (6, 8 and 10 mm) and materials (polylactic acid (PLA), PLA-Carbon and PLA-Wood). The results show that increasing the core density enhances compressive strength, modulus, and energy absorption. An 8 mm unit cell absorbs energy optimally for lightweight structures. In PLA flatwise testing, the 8 mm unit cell absorbed 419.49 J more energy than the 10 mm unit cell. Additionally, PLA-Wood has better mechanical performance than PLA-Carbon due to the better filler with the PLA- matrix. In flatwise testing with an 8 mm unit, PLA-Wood absorbs 214.01 J, while PLA-Carbon absorbs 122.49 J. The failure modes vary depending on tests performed. The study highlights the potential of 3D-printed honeycomb core structures for load-bearing applications in various industries, including aerospace and automotive. Highlights: Quasi-static loading behavior of 3D-printed hexagonal honeycomb cores. Increased core density improves compressive stress, modulus, and absorbed energy. An optimal unit cell size for lightweight 3D printed core structures is 8 mm. PLA-Wood performs better in energy absorption due to filler compatibility. The failure modes are related to the type of quasi-static loads applied.
      10  37
  • Publication
    Tribological Behaviour of Furcraea Foetida Fiber-Reinforced Epoxy Composites under Varying Applied Loads
    This study investigates the tribological behaviour of Furcraea Foetida fibre-reinforced epoxy composites under varying applied loads. The aim is to understand the influence of applied load on the frictional behaviour and wear characteristics of the composites. The study employs a pin-on-disk test to examine the frictional force, coefficient of friction (COF), and specific wear rate (SWR) of identical samples subjected to four different loads (80 N, 100 N, 120 N, 140 N). Scanning electron microscopy (SEM) is used to analyse the surface morphology under different loads. The frictional force versus sliding distance graph demonstrates an increasing trend from 80 N to 120 N, followed by minimal change at 140 N. Similarly, the COF versus applied load graph shows a progressive increase from 80 N to 120 N, with the least increase observed at 140 N. The SWR versus applied load graph indicates an increasing trend from 80 N to 120 N, with marginal variation at 140 N. SEM analysis reveals that only the sample subjected to 140 N shows evidence of plastic deformation. In conclusion, the results indicate that the applied load significantly influences the frictional behaviour and wear characteristics of the Furcraea Foetida fibre-reinforced epoxy composites. At higher loads, the increase in frictional force, COF, and SWR becomes less pronounced, suggesting potential saturation in the composites' response. The presence of plastic deformation at 140 N further highlights the unique behaviour observed at this load. These findings contribute to a better understanding of the tribological performance of the composites and have implications for their practical applications.
      4  20
  • Publication
    Low-velocity impact behavior of sandwich composite structure with 3D printed hexagonal honeycomb core: varying core materials
    Additive manufacturing technology is extensively used in aeronautical applications, especially in designing the sandwich composite structures for repair tasks. However, the composite structures are vulnerable to impact loadings because of their exposure to, for instance, loading field carriages, flying debris, and bird strikes. This may lead to crack propagation and ultimately the structural failure. Therefore, it is important to investigate the mechanical behavior of sandwich composite structures under low-velocity impact. In this research, carbon fiber fabric reinforced 3D-printed thermoplastic composite of hexagonal honeycomb cores structures were fabricated with different unit cells (6, 8, and 10 mm) and varying materials (polylactic acid (PLA), PLA-Wood and PLA-Carbon). A drop weight impact test was performed under impact energies (5, 8, and 11 J) to determine the energy absorption performance of the structures whereas the surface morphology was analyzed using a high-intensity optical microscope. Comparing unit cells of materials used, it is observed that the unit cell of 8 mm is the best configuration for lightweight materials with impressive energy absorption capabilities. Under an impact energy of 11 J, the PLA-Wood of unit cell 8 mm shows 9.22 J higher in energy absorption than unit cell 10 mm which is 7.44 J due to intermediate stiffness that resists further deformation. While the filled PLA shows the PLA-Wood material offers better performance in energy absorption capability compared to PLA-Carbon. The PLA-Wood demonstrates 9.22 J more energy absorption for an unit cell 8 mm under an impact energy of 11 J than the PLA-Carbon, which is 8.49 J. This is due to the good compatibility between the hydroxyl groups of the polymer matrix and lignocellulose filler, which translates to better stiffness.
      2
  • Publication
    Shrinkages and warpage in the processability of wood-filled polypropylene composite thin-walled parts formed by injection molding
    ( 2013-07-01) ;
    S.M. Sapuan
    ;
    S. Sulaiman
    ;
    E.S. Zainudin
    ;
    A. Khalina
    Reducing volumetric shrinkages and warpage during the injection molding process is a challenging problem in the production of molded thin-walled parts. In this study, the injection molding of shallow, thinwalled parts (thickness 0.7 mm), composed of lignocellulosic polymer composites (polypropylene (PP) + 50 wt% wood), was simulated. The volumetric shrinkages and warpage in the thin-walled parts were evaluated under different process conditions, with varying post-filling parameters, such as mold temperature, cooling time, packing pressure and packing time. The analysis showed that the cooling time and packing time had less of an effect on the shrinkage and warpage; nevertheless the optimal levels for both parameters are required in the molding process for the thin-walled part to achieve the best results. The volumetric shrinkage was lower near the gate than at the end-of-fill location along the flow path. The results also showed that the volumetric shrinkage correlates with the warpage measured on the molded part. The optimum parameters ranges is 40–45 C for the mold temperature; 20–30 s for cooling time; 0.85 from injection pressure (Pinject) for packing pressure; and 15–20 s for the packing time to achieve the best results with the least amount of volumetric shrinkage and warpage.
      3  21
  • Publication
    Tensile properties of hybridised fire retardants in pineapple leaf fibre (PALF) reinforced polymer composites
    This paper presents the tensile properties of hybridised fire retardants Pineapple Leaf Fibre (PALF) reinforced polymer composite. The polymer composites were prepared using the hand lay-up method of fabrication, in which two-layer PALF was used, and the epoxy resin with the fire retardants were mixed. The non-hybridised fire retardants are ammonium polyphosphate (APP), magnesium hydroxide (MH) and aluminium hydroxide (ALH), while the hybridised fire retardants are ammonium polyphosphate/magnesium hydroxide (APP/MH), ammonium polyphosphate/aluminium hydroxide (APP/ALH) and magnesium hydroxide/aluminium hydroxide (MH/ALH). The samples were tested using the universal testing machine with load cell 50kN using ASTM D3039 standard. The samples APP/ALH and MH/ALH have better tensile strength, which is 37.10 MPa and 37.05 MPa, respectively. The dispersion of fire-retardants in the reinforced composites seems to affect their mechanical performance. Meanwhile, sample MH/ALH has the highest elastic modulus with 3.65 GPa. Sample MH/ALH likely to be an excellent hybridised fire-retardant filler for the composites.
      5  20
  • Publication
    Synthesis and characterization of natural fiber reinforced polymer composites as core for honeycomb core structure: a review
    Researchers have worked on variety of natural fibers reinforced with polymer composites using different parameters to come up with various recommendations. The investigation involved aspects of composition materials and mechanical properties of natural fiber composites. The satisfactory results of natural fiber composites have encouraged researchers to delve deeper into the abilities of natural fiber composite in the form of a core structure. The potentiality of utilizing natural fiber composite in core design has wide potential in modern industries. This paper presents a review on natural fibers and polymer matrices commonly used in core fabrication, core design, fabricating processes of cores, and mechanical properties of cores. Ongoing research of rice husk composites to be fabricated in the form of honeycomb core structures is also discussed.
      8  1