Low velocity impact response of laminated textile coir-aramids/epoxy hybrid composites subjected to transverse penetration loading

The hybrid of natural and synthetic fibres in a composite system has gained interest in research field due to the environmental consciousness. Coir natural fibre has been found to have a high potential as impact resistance, in which brittle fibre helps to spread the impact energy over a wider area. The focus of the study is to determine if any improvement in impact response exists as a result of combining high performance Kevlar synthetic fibre and coir natural fibre in a specified laminated stacking sequence. In this research, quasi-static experiments were conducted at the speed of 1.25 mm/s, and low velocity impact tests were conducted using a 12.7 mm hemispherical impactor at the speed varying from 5 m/s to 17 m/s. Matlab software was used for curve fitting of the raw data, whereas ANOVA and DOE via Minitab software were employed for statistical examination to support the results. The area of the damaged composite was evaluated using the image analysis technique by Matlab image processing tool. The morphology analysis of the impact fractured surfaces was also observed by SEM. At the beginning stage, the optimum impact responses of coir epoxy composites subjected to different reinforcement architecture, composite manufacturing method, fabric modification and fabric density were determined. The findings showed that the impact responses could be effectively controlled by varying material parameters. Coir fibre in the form of woven structure with dense structure, treated using 6% of NaOH solution and manufactured by compression moulding method was found to be effective in absorbing and propagating impact energy. The respective coir was then used in hybrid laminates. Coir/Kevlar epoxy hybrid composites consisted of three interply laminates layers at six different stacking configurations were developed. It was observed that the hybrid composite (two coir layers and one Kevlar layer) had equivalent specific total energy absorption as 100% Kevlar laminate (at three layers). It can be concluded that the hybrid of coir/Kevlar-epoxy laminated composites had shown an improved in impact response. It also provides cost-effective materials and contributes towards green technology which will be of great benefit to the industry and community

Protective coating for gabion wires against weathering elements and site conditions

Gabions are one of the most essential elements in the geotechnical field for their versatility and strength in slope stabilization. According to BS 8002:2015, gabions are rectangular large cages or baskets made of either steel wire or square welded mesh, and are usually filled with stones. Besides slope stabilization, gabions have been widely used for various purposes, including closing of river banks, road construction, landslide consolidation and hilly terrain reclamation [1]

The effects of lawsonia inermis pigmentation for superhydrophobic properties on cotton fabrics

Nowadays, there are many things that can be produced easily by the help of modern technologies. This include the synthetic materials that can be developed by using any advance machine that was manufactured [1]. However, those synthetics materials that was developed may bring harm to the environment. Their particles can be spread resulting an unhealthy atmosphere. Thus, the natural resources was used to produce an authentic materials (Calarge, 2018). In the recent years, textile industry has been developed significantly and contributes to the growth of Malaysia’s economy [2]. It can be categorized as one of the complicated industries among the manufacturing industries such as food, cosmetics and pharmaceutical industries [3]. Thus, the textile industries require high water consumption and resulting on high discharge rate of wastewater that loaded with contaminants [2]. The generation of wastewater from textile industry comes from the manufacturing process of textile fabrics such as washing scouring bleaching, mercerizing, and dyeing and finishing process. The highest amount of wastewater that produced from textile industries come from the process of dyeing and finishing. The contaminants of water that produced by dyeing and finishing process include high suspended solids (SS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), heat, colour, acidity, basicity, and other organic pollutants [4]. This matter has to be seriously concerned as it may lead to allergic responses, eczema, and also affect the liver, lungs, and immune system of humans as well as animals [3]. The purpose for the project of the effects of Lawsonia Inermis was basically to produce a natural pigment that may not harm the environmen

Numerical simulation analysis on water jet pressure distribution at various nozzle aperture

The low velocity water jet is required by small scale Unmanned Underwater Vehicle (UUV) to control its position, either to remain statics in its position or to perform a slow and steady locomotion. However, the water jet performance is influenced by the size of nozzle aperture. By studying the pressure distribution around the nozzle area, the water jet velocity could be determined and characterized. In this studies, the ejection pressure was fixed at 23.37 Pa according to the constant actuation. Studies were conducted using ANSYS Fluent software. The results show that the water jet velocity and dynamic pressure are higher for larger nozzle aperture size at constant pressure. The total pressure and dynamic pressure had the lowest pressure drop at certain nozzle aperture size but became constant when the nozzle size was wider. This finding is useful in designing the UUV that powered by contractile water jet thruster

Enhancing the bearing capacity of rigid footing using limited life kenaf geotextile reinforcement

This research focuses on soft clay improvement by using Kenaf textile as a natural geotextile reinforcement. A series of small-scale laboratory tests were conducted to study the impact of the geotextile reinforcement depth, d, the vertical spacing between reinforcement, S and the number of reinfor- cement layers, N on the bearing capacity of the soil model. The test results were verified using the numerical simulation by PLAXIS 2D. In this study, the influence factors included four different d/B ratios of 0.25, 0.5, 0.75 and 1.0; three different S/B ratios of 0.25, 0.5 and 0.75, and a different number of reinforcement layers, N from 1 to 4 were investigated where B is the footing width. The results clearly showed that the bearing capacity of rigid footings was significantly improved with the Kenaf geotextile layers in the kaolin. The measured and predicted bearing capacity results were in good agreement. The optimum d/B ratio and S/B ratio, which resulted in the maximum ultimate bearing capacity of the Kenaf-reinforced model ground were about 0.25 and 0.25, respectively. The optimum N was 3, i.e., the bearing capacity insignificantly improved even with N > 3

Chemical effect on the mechanical properties of bamboo fiber for textile: a review

The needs on sustainable fiber of bamboo for textile and non-textile materials are never being doubt. The mechanical properties of bamboo fibers are unique among their species. Thus, this fiber requires a unique process to be implemented in order to meet their application. Often, previous studies had adopted various fiber extraction and treatment yet these processing were affected their physical and mechanical properties. Chemical treatments are often being applied onto natural fibers such as bamboo in order to improve crucial properties subjected to textile processing capability. Specifically, the treatment partially removes the cellulosic and non-cellulosic contents of the bamboo fiber bundle such as hemicellulose, lignin and pectin. An appropriate concentration of alkaline usage in treating bamboo fiber could obtain the optimum mechanical and physical performance along with the changes of its surface morphological. This paper provides a brief review on the published reports concerning on anatomical, chemical composition and physical of bamboo. The effect of alkaline treatment on bamboo fibers have been discussed and reviewed in terms of their mechanical behavior and physical properties

Extraction of eco-friendly natural dyes from Pina leaves and their application on wool fabrics

Natural dyes comprise of colorants that are obtained from animals or vegetable matters without any chemical processing. Natural dyes can substitute synthetic dye and promotes green technology initiatives in the field of textile dyeing. This study was carried out by extracting dyes from pineapple leaves (Ananas Comosus) using three stage mordanting methods using different mordants namely premordanting, post-mordanting and simultaneous dyeing-mordanting. The mordants used were aluminium potassium sulphate, white vinegar and sodium chloride (NaCl). Wool fabrics were used for dyeing. The strength of colour and K/S values of the dyed fabrics were measured before and after washing. The colourfastness to washing, rubbing and light fastness of the fabrics were conducted to investigate the performance of the dye and mordants. The results indicate that the washing, rubbing and light fastness properties of dyed samples were between good to excellent grades

The influence of physical properties on comfort performance of bedsheet fabrics

This paper analyzes the comfort performance of different types of bedsheet fabrics which are polyester, polyester blended with Tencel, cotton, Tencel and modal. The objectives of this study are to determine the physical and comfort properties of bedsheet fabrics as well as to evaluate the influence of physical properties on the comfort performance of bedsheet fabrics. The preparation of samples involved sourcing the fabrics that are commercially used. Physical properties such as thickness, mass per unit area and porosity were determined in order to evaluate their relationship on comfort properties such as thermal resistance, wicking area and water vapour transmission rate (WVTR). It was found that Tencel fabric exhibited the lowest thermal resistance of 0.0037 m2 °C/W while polyester fabric showed the highest thermal resistance of 0.0084 m2 °C/W. For wicking area, polyester blended with Tencel fabric demonstrated the highest wicking area whereas Tencel fabric displayed the highest WVTR of 1069.21 g/24h.m2 . Based on findings, Tencel bedsheet could offer better comfort in hot environment as the heat and water vapour can pass through the fabric easily compared to other fabrics. Meanwhile, polyester bedsheet will offer better comfort in cold environment as it can retain the heat and this can help the users to feel warmer in cold environment

Effects of sulphuric acid concentrations during solvolysis process of carbon fiber reinforced epoxy composite

Developing a cost-effective technique of reclaiming carbon fibers without significantly deteriorating their quality has gained much importance. This paper reports on reclaiming carbon fibers from the carbon fiber reinforced polymer (CFRP) by solvolysis technique using sulphuric acid. The main objective of this work was to determine the lowest sulphuric acid concentration which can remove the epoxy resin from the composites, at room temperature and atmospheric pressure. The sulphuric acid concentrations used ranged from 11 to 18 mol L-1 with 30 min reaction time and 50 mL volume. Thermogravimetric analysis (TGA) showed that the fiber content of the composites is 68% by weight. From the solvolysis process, mass of decomposed epoxy resin decreased with decreasing acid concentrations. SEM images show that the residual epoxy adhering to the fibers after solvolysis increased with decreasing molarity. Acid concentrations lower than 15 M were found to be not effective in removing the epoxy resin from the carbon fibers. The tensile strength and Young’s modulus of all the reclaimed fibers is marginally lower than the untreated carbon fibers. The tensile strength was found to increase as the acid concentration decreases with fibers in 15 M acid showed the highest tensile strength of 3.43 GPa (99.1% strength retention). Similar trend was also observed for Young’s modulus. The study shows the potential of sulphuric acid to reclaim carbon fiber from the CFRP with 15 M giving the optimum properties in terms of tensile properties retention and epoxy resin decomposition

Factorial Analysis of Tensile Properties of Areca Leaf Sheath (ALS) Subjected to Flattening

Areca leaf sheath (ALS) is a common agricultural waste produced in Southeast Asia countries, which is widely utilized over the decades to make biodegradable disposable dining wares. The workable surface of ALS for heat pressing is limited due to the concavity in the middle and folding at the edges of ALS. This study proposes that the ALS is flattened using a padding mangle prior to the forming process. The aim is to investigate the effect of ALS thickness and flattening pressure on the ultimate tensile strength and strain at break of ALS. A range of factors influencing the flattening process were investigated using design of experiment (DOE) approach based on analysis of variance (ANOVA). As the applied pressure increases, the thickness reduction of the ALS also increases. The tensile test was carried out in accordance to ASTM D3039 standard. It is found that ALS thickness and flattening pressure affect the results differently. The highest ultimate tensile strength (23.25 MPa) is obtained from 3-4 mm thick grain direction samples flattened at 5 bar; whereas the highest strain is 58.28% from perpendicular grain direction samples flattened at 1 bar, with thickness range of 3-4 mm. The results suggest that flattening process does not influence the tensile strength of ALS significantly when it is fed in parallel direction; but decreases the strain slightly