Yakub Md. Taib

Tensile strength of notched woven fabric hybrid glass, carbon/epoxy composite laminates:

This study investigates the effect of hybridization on tensile strength of woven fabric glass/epoxy composite laminates with two different notch sizes of 5 mm and 10 mm. Tensile tests are performed on notched [0°/90°]3s specimens of woven fabric C-glass/epoxy composite laminates and their hybrid reinforced with woven fabric 3K-carbon layers in order to measure tensile strength and characterize damage mechanisms. The results suggest that hybridization has a considerable effect on the improvement of the tensile strength of C-glass/epoxy composite laminates but also has reduced the rupture strain of the composites. Microscopic observation of specimens after tensile loading reveals the existence of transverse and longitudinal cracks, delamination and transverse fiber damage in hybrid composite laminates.

Comparison of electrical physical and mechanical properties of textile composites using microwave nondestructive evaluation

Composites are expensive and destructive test methods are normally applied to determine their physical and mechanical properties. For textile composites, a nondestructive test (NDT) could save time and save cost if the physical properties such as moisture content, weave architecture, void content and fiber volume fraction can be deduced from electrical properties. Also, there would be savings if mechanical properties such as tensile stress and elastic modulus could be determined by NDT methods. In this research, microwave NDT (MNDT) techniques such as measurement of complex permittivities are used for correlation with physical and mechanical properties. For textile composites made from E-glass, Kevlar and carbon fiber, we have measured reflection coefficients, transmission coefficients and dielectric properties using a free-space microwave measurement system. Epoxy has been used as a resin. Experimental results are reported for dielectric constants and loss tangents of textile composites. Also, measured physical and mechanical properties of textile composites are reported.

Effect of Low Impact Energy on Kenaf Composite and Kenaf/Fiberglass Hybrid Composite Laminates

Kenaf fibres recently have been a substitute material in many weight-critical applications such as aerospace, automotive and other industrial sectors. Their characteristics, such as low densities, specific strength and specific modulus are considered superior to those of metallic materials. The tensile and low velocity impact of kenaf composites and kenaf/fibreglass composites were investigated. The findings of such revealed that the tensile properties of the composites were seriously impaired even when low energy was used. As for hybrid composites, the tensile properties were hardly affected when tested with energy of below (6J). However, the tensile properties were reduced after the energy increased above (6J). Therefore, the impact damage of the composites can be predicted from measurements taken from the residual tensile strength of impacted specimens, and the damaged zones of the composites.

Impact Toughness of Kenaf Powder, Polypropylene and Kevlar

mpact and tensile properties were carried out on Kenaf Powder (K) Polypropylene (PP) reinforced with Kevlar (KV) composites plate prepared in-house using hot press technique. The effect of bonding agent, Maleic Anhydride grafted Polypropylene (MAPP), on the strength and impact toughness was also conducted. The size of kenaf powder used was limited to 100μm. The kenaf/polypropylene composite designated as KPP specimens were tested through tensile test (ASTM D 638) and izod test (ASTM D256) for 20-40% weight ratio of kenaf powder. The optimum weight ratio of KPP sample was selected and then underwent for the drop impact testing. The selected KPP sample was further reinforced with Kevlar cloths. This hybrid composite is designated as KPP/KV sample and further tested in izod impact and drop tests. The impact toughness of KPP reinforced with KV is almost 4-6 times without KV. There are also slight improvements in the impact toughness of the KPP/KV samples with MAPP.

Slurry wear test of long kenaf polyester composite (LKPC) and long kenaf polyester with fiberglass composite

This paper presents an experimental study on the influence of fiberglass woven in Long Kenaf Polyester Composite (LKPC). Wear and friction characteristics were examined using sea water and sand as a slurry. Wear test were carried out using Slurry Erosion Test Rig (TR-40). These tests were performed at room temperature with speed of 200 rpm for every 2 km interval. The results from the tests show that mass loss were depends on the matrix composition of the composite. Surface Roughness, Ra, was consistently reduced after each test in all cases.

Three Response Optimization of Spot-Welded Joint Using Taguchi Design and Response Surface Methodology Techniques

One of the main challenges in correlating welding parameters and weld quality is its complexity to include as many as possible factors. In this research, the effects of spot welding parameters on weld quality were investigated. The effects of weld time, weld current, and electrode force on the sizes of fusion zone and heat affected zone, and tensile-shear load were studied. These welding parameters and weld quality were analysed using the three response Taguchi L9 orthogonal array method in Minitab 17. Second-order regression models of fusion zone size, heat affected zone size and tensile-shear load were constructed by adapting Response Surface Method. The optimum weld time was 0.2 s, weld current of 10 kA and the required electrode force was 2.3 kN. These parameters were within 5% discrepancies with the experiment results. Weld current was the most important welding parameter that determines the weld quality, with the contribution of 69%. From our observation, the failure mode was the pullout type, a generally accepted failure for welded joint. The outcomes of this research contributed to the advancement in optimization technique for RSW joint, by increased the number of weld quality from two to three response.

Tensile and Impact Strength of Coir Fibre Reinforced Polypropylene Composites: Effect of Different Temperature Conditions

This study focuses on tensile properties and impact strength of coir fibre reinforced polypropylene composites under influences of fibre loading and various temperatures conditions. All samples were fabricated by using hot-press technique. Tensile and izod impact samples were prepared in accordance to the standard specifications as closely as possible. Three different ratios of fibre with matrix which were 10%, 20% and 30% were studied. The results revealed that 20% volume fraction of coir fibre demonstrated optimum tensile and impact properties. Significance reduction of impact strength under low temperature condition had been shown for all composites due to the brittleness of both fibre and matrix.

Effect of Water Absorption on Mechanical Properties of Kenaf and Kenaf Hybrid Polyester

Natural fibre composite materials have been highlighted in recent years as they have the potential to mitigate the pollution and global warming. Kenaf is a high yield and fast growing plant. Kenaf does not require a lot of energy in production. Furthermore, the kenaf plant can absorb carbon dioxide when breathing. The objective of this paper is to relate the effect of different environment to the mechanical properties of kenaf and kenaf hybrid (fiberglass) polyester composites for 60 days period. Kenaf composite (containing 20 wt% of Kenaf fibres) and kenaf hybrid (containing 20 wt% kenaf fibre and 16 wt% fiberglass) were produced in cold press hand lay-up technique and then cured for 24 hours. The specimens were cut as required in EN ISO 527. The specimens were immersed in 3 different water sources, which were rain water, salt water and tap water. Tensile and hardness test were conducted to study the mechanical properties at 10, 20, 30, 40, 50 and 60 days. Both kenaf polyester and kenaf hybrid polyester show reduction on mechanical properties after immersion in the solutions. Kenaf polyester and kenaf hybrid polyester followed fickian behaviour after 40 days water immersion.

Fracture toughness of treated OPEFB filled polymer nanocomposites at different clay loading

Two different clay loadings were added to OPEFB/PP/MAPP which was 7 phr and 10 phr in order to see its effect on the fracture toughness. Standard dimension of samples was prepared for 180 μm, 355 μm and 355 μm treated with 1% NaOH. The result showed that 7 phr clay contents had the highest fracture toughness of 1.16 MPa.m1/2. Alkali treatment on OPEFB fiber gave 7% improvement of fracture toughness for samples with 7 phr PPnanoclay loading. SEM images show the improvement of bonding between the fibers and the matrix upon alkali treatment.