Behavior Of Natural Fiber Composites Research Articles

Tribological, mechanical, and metallurgical performance of natural fiber-reinforced composites: A comprehensive review

Composite materials have an ever-increasing demand for their application in numerous applications such as aerospace, automobile, petroleum, etc. These materials vary according to their chemical composition, properties, manufacturing techniques, etc. Natural fiber-reinforced composites are the composites where natural fibers such as plant, animal, and mineral fibers are used as reinforcement material. Reinforcement of these fibers yields composite material with extensive properties such as high strength, durability, reliability, etc. These properties lead them to commercial applications in several areas. Therefore, this paper describes various characteristics of the matrix, reinforcement, and resin used for natural fiber composite materials. Also, multiple parameters that affect the growth of these composites are investigated. The tribological behavior of natural fiber composites is focused mainly on friction, wear, and lubrication. Furthermore, the material's mechanical performance and metallurgical behavior are also given significant importance. These materials’ application in various fields is explored separately, and multiple conclusions are drawn.

Fatigue behaviour of Kevlar/carbon/basalt fibre-reinforced SiC nanofiller particulate hybrid epoxy composite

Abstract It is vital to conduct research on the behaviour of natural fibre composites under cyclic loading in order to have confidence in the mechanical durability. During this study, the fabrication of composite laminates will be carried out by the hybridization effect of natural and synthetic fibres. Quantifying the impact that the SiC filler (10, 20, and 30 g) has when combined with the fibre reinforcement and epoxy matrix (275 g) under cyclic loading circumstances and determining the significant sequence of hybrid composites are the goals of this research. The results of the tensile mode were used to determine the input parameters, and based on the tensile strength of the hybrid composite, 70% of the tensile strength was fixed at 3 Hz frequency as the input for fatigue analysis. The life span was then determined for the hybrid composite. The results of this fatigue test showed that increasing the amount of SiC nanofillers produced a very high potential output for the fatigue test. As a result of increasing the amount of silicon carbide fillers from 10 to 30 g, sample S3 was able to significantly tolerate 65% more life. Failure mode can be identified from scanning electron microscope analysis revealing the major porosity, matrix crack, and laminate bonding strength that causes the failure during fatigue analysis.

The Interaction Effect of the Design Parameters on the Water Absorption of the Hemp-Reinforced Biocarbon-Filled Bio-Epoxy Composites.

Natural fiber-reinforced composites perform poorly when exposed to moisture. Biocarbon has been proven to improve the water-absorbing behavior of natural fiber composites. However, the interaction effect of the design parameters on the biocarbon-filled hemp fiber-reinforced bio-epoxy composites has not been studied. In this study, the effects of the design parameters (pyrolysis temperature, biocarbon particle size, and filler loading) on the water absorptivity and water diffusivity of hemp-reinforced biopolymer composites have been investigated. Biocarbon from the pyrolysis of hemp and switchgrass was produced at 450, 550, and 650 °C. Composite samples with 10 wt.%, 15 wt.%, and 20 wt.% of biocarbon fillers of sizes below 50, 75, and 100 microns were used. The hemp fiber in polymer composites showed a significant influence in its water uptake behavior with the value of water absorptivity 2.41 × 10-6 g/m2.s1/2. The incorporation of biocarbon fillers in the hemp biopolymer composites reduces the average water absorptivity by 44.17% and diffusivity by 42.02%. At the optimized conditions, the value of water absorptivity with hemp biocarbon and switchgrass biocarbon fillers was found to be 0.72 × 10-6 g/m2.s1/2 and 0.73 × 10-6 g/m2.s1/2, respectively. The biocarbon at 650 °C showed the least composite thickness swelling due to its higher porosity and lower surface area. Biocarbon-filled hemp composites showed higher flexural strength and energy at the break due to the enhanced mechanical interlocking between the filler particles and the matrix materials. Smaller filler particle size lowered the composite's water diffusivity, whereas the larger particle size of the biocarbon fillers in composites minimizes the water absorption. Additionally, higher filler loading results in weaker composite tensile energy at the break due to the filler agglomeration, reduced polymer-filler interactions, reduced polymer chain mobility, and inadequate dispersion of the filler.

Uncertainty analysis of mechanical behavior of natural fiber composites

The natural origin of the fibers combined with random production flaws results in significant uncertainties in the properties of natural fiber-reinforced composites. A probabilistic assessment can help to characterize the uncertainties and evaluate the reliability of natural fiber composites, enabling their use in engineering designs. To this end, this study aims to analyze the uncertainties in the tensile strength and frequency response of a unidirectional flax/epoxy composite due to the actual variability of various input parameters, including the fiber material properties and manufacturing flaws. Based on the available data in the literature, the non-deterministic input variables were divided into normal and uniform variables using a statistical test. A computationally efficient response surface approach based on the polynomial chaos expansion was proposed to conduct the uncertainty analysis with multi-type uncertain variables. Moreover, the results were validated by experimental measurements and compared with the direct Monte Carlo simulation to demonstrate the accuracy and efficiency of the surrogate model.

Mechanical and Rheological Behaviour of Composites Reinforced with Natural Fibres.

The paper deals with the mechanical behaviour of natural fibre composites subjected to tensile test and dynamic mechanical analysis (DMA). Three types of natural fibre composites were prepared and tested: wood particle reinforced composites with six different sizes of grains (WPC); hemp mat reinforced composites (HMP) and flax reinforced composite with mixed wood particles (FWPC). The tensile test performed on universal testing machine LS100 Lloyd’s Instrument highlights the elastic properties of the samples, as longitudinal elasticity modulus; tensile rupture; strain at break; and stiffness. The large dispersion of stress–strain curves was noticed in the case of HMP and FWPC by comparison to WPC samples which present high homogeneity of elastic–plastic behaviour. The DMA test emphasized the rheological behaviour of natural fibre composites in terms of energy dissipation of a material under cyclic load. Cole–Cole plots revealed the connection between stored and loss heat energy for studied samples. The mixture of wood particles with a polyester matrix leads to relative homogeneity of composite in comparison with FWPC and HMP samples which is visible from the shape of Cole–Cole curves. The random fibres from the hemp mat structure lead to a heterogeneous nature of composite structure. The elastic and viscous responses of samples depend on the interface between fibres and matrix.

Flexural and Izod Impact Properties of Sugarcane Powder Reinforced Epoxy Composite

Currently, the studies of the mechanical behaviour of natural fibre composites have become influential among researchers due to its environmentally friendly, useful by-product and cheap. Due to this it becomes a potential material to be included in the composite materials as a reinforcement. The aim of this study is to investigate the mechanical properties of sugarcane powder reinforced epoxy composites under flexural and Izod impact tests. The sugarcane powder was processed using the crushing machine and planetary mono mill machine and it was added into the epoxy matrix with four different compositions (5 vol%, 10 vol%, 15 vol%, and 20 vol%). The morphological surfaces of the composite after the mechanical tests were observed using a Scanning Electron Microscope (SEM). It was found that the impact strength of the composites decreased with the increase of powder compositions with a range of between 5.7 kJ/m2 to 2.7 kJ/m2. The flexure modulus, on the contrary, showed an increment trend with the increase in powder loading with a modulus ranged in between 757 MPa to 1208 MPa. The potential of this natural fiber have significant contribution on the properties of natural fibres polymer composites. Natural waste consumption of sugarcane fiber could decrease the usage of synthetic polymers and provide the environmental friendly material for further application.

Thermal effect on the tribo-mechanical behavior of natural fiber composites at micro-scale

This paper aims to explore the thermal influence on the micro-tribo-mechanical behavior of natural fiber composites. Nanoindentation and scratch-test are used to characterize flax fibers reinforced polypropylene (PP) composites. Results show a different thermo-mechanical behavior between flax fibers and PP matrix. While the stiffness of PP matrix decreases by increasing the sample temperature, the stiffness of flax fibers shows an increase then a decrease by changing the sample temperature from 25 °C to 100 °C with a maximum at 60 °C. This attests to a modification of the chemical composition of flax fibers when increasing the temperature. The specific thermo-mechanical behavior of flax fibers affects their friction comportment at a high sliding speed which demonstrates that the tribology of NFRP composites is thermo-mechanical-dependent.

Stiffening effect of fatigue and creep loading in unidirectional flax fibre/epoxy composites

A study related to the fatigue behaviour of natural fibre composites was conducted to expand their industrial applications. Unidirectional flax/epoxy composites were fabricated, and their fatigue and creep behaviour was investigated by applying a range of different testing conditions. Stiffness was found to increase during fatigue loading, and this was accompanied by accumulation of residual strain. By arranging the results in a stiffness-strain diagram, a linear trend was established with a positive slope representing the stiffening effect. A similar linear trend was obtained for creep loading, however, with a larger stiffening effect. For fatigue loading, the stiffening effect was found to be changed by the applied cycle frequency. The combined findings in the study suggest that stiffness change in the composites is reflecting a balance between stiffening due to residual strain, and softening due to fatigue damaging.

Review on mechanical properties of natural fiber composites.

The present experimental study aims at learning the mechanical behavior of natural fiber composites. Natural fibers have an attracting the interest to engineers, researchers, professionals and scientists all over the world as an alternative reinforcement, because of its superior properties such as high specific strength, low weight, low cost, fairly good mechanical properties, non-abrasive, eco-friendly and bio-degradable characteristics. A brief review has been carried out to make use of natural fibers (such as abaca, jute, sisal, banana, cotton, coir, hemp, etc) abundantly available in India. This paper presents a review on the mechanical properties of Abaca, Jute, Sisal.

Acoustic Absorption of Natural Fiber Composites

The current study is a bibliographic observation on prevailing tendencies in the development of acoustic absorption by natural fiber composites. Despite having less detrimental environmental effects and thorough availability, natural fibers are still unsuitable for wide implementation in industrial purposes. Some shortcomings such as the presence of moisture contents, thicker diameter, and lower antifungus quality hold up the progress of natural fiber composites in staying competitive with synthetic composites. The review indicates the importance of the pretreatment of fresh natural fiber to overcome these shortcomings. However, the pretreatment of natural fiber causes the removal of moisture contents which results in the decrease of its acoustic absorption performance. Incorporation of granular materials in treated fiber composite is expected to play a significant role as a replacement for moisture contents. This review aims to investigate the acoustic absorption behavior of natural fiber composites due to the incorporation of granular materials. It is intended that this review will provide an overview of the analytical approaches for the modeling of acoustic wave propagation through the natural fiber composites. The possible influential factors of fibers and grains were described in this study for the enhancement of low frequency acoustic absorption of the composites.

Effect of cenosphere on mechanical properties of bamboo–epoxy composites

Cenosphere is a ceramic-rich industrial waste produced during burning of coal in thermal power plants. This study deals with the effect of cenosphere as particulate filler on mechanical behaviour of natural fibre composites. The natural fibre composite consists of bamboo fibre as reinforcement and epoxy as matrix. The bamboo fibre is treated with alkali to improve its surface properties. The conventional hand lay-up technique is used to prepare different composite specimens. Twenty numbers of different composite specimens are prepared with varying number of laminae and filler content. The samples are analysed for their mechanical properties to establish the effect of varying filler content and the number of laminae. It is found that the mechanical properties are significantly influenced by addition of this waste-based ceramic filler.

Mechanical behavior of natural fiber composites

The use of natural fibers as reinforcement in polymeric composites for technical applications has been a research subject of scientists during the last decade. There is a great interest in the application of sisal fiber as substitutes for glass fibers, motivated by potential advantages of weight saving, lower raw material price, and ecological advantages of using green resources which are renewable and biodegradable. Castor oil, a triglyceride vegetable that has hydroxyl groups, was reacted with 4,4’ diphenylmethane diisocyanate (MDI) to produce the polyurethane matrix. Woven sisal fibers were used untreated and thermal treated at 60°C for 72h, and the composites were processed by compression molding. The present work study tensile behavior at four composites: dry sisal/polyurethane, humid sisal/polyurethane, dry sisal/phenolic and humid sisal/phenolic resin. The moisture content influences of sisal fibers on the mechanical behaviors were analyzed. Experimental results showed a higher tensile strength for the sisal/phenolic composites followed by sisal/polyurethane, respectively. In this research, sisal composites were also characterized by scanning electron microscopy.

Mechanical and Biodegradation Behavior of Natural Fiber Composites

This paper deals with the characterization of high strength and functional natural fiber reinforced composite materials which are fabricated using starch-based biodegradable resin and Manila hemp fiber. Hemp fiber reinforced cross-ply composites were prepared by a conventional hot-pressing method. Their mechanical characterization was carried out by evaluating tensile strength as a function of fiber content. It can be seen that the tensile strength of the cross-ply composites was saturated over 50 wt% due to the interaction between warp and weft during the hot-pressing. However in the case of flexible weft; such as cotton thread or resin fiber, the tensile strength of the cross-ply composites almost linearly increased with increasing fiber content. The biodegradation behavior of the hemp fiber reinforced unidirectional composites was also examined by burying them into compost media. The changes in surface morphology of the specimen and in specimen weight loss were monitored for 30 days. It is apparent that the natural fiber reinforced composites showed an enhanced biodegradation speed. This enhanced biodegradation behavior seems to be derived from increased apparent surface area of the composite specimen due to the preferential biodegradation at interface between hemp fiber and biodegradable resin as well as the preferential water transportation through internal cavity in hemp fiber.

Acoustical properties of Lyocell, hemp, and flax composites

This study characterizes the acoustical behavior of natural fiber composites. Regenerated cellulose fibers (Lyocell), hemp fibers, and flax fibers were embedded in an epoxy-matrix. These unidirectional composites were tested for their logarithmic damping decrement, the resonance frequency, the ultrasound velocity, the dynamic and static modulus of elasticity, and bending strength and density. Glass-epoxy composites served as a reference. All tested cellulosic fibers showed a significantly higher damping at lower densities. The ultrasound velocity was in the range of the reference for Lyocell— and hemp—fiber composites. Taking the low density into account, the dynamic and static modulus of elasticity of the samples were relatively high compared to the glass reference. The specific acoustical properties of these natural fiber composites point at high value applications, e.g., devices that require high damping of the body structures.

Influence of Coupling Agents on Melt Flow Behavior of Natural Fiber Composites

AbstractThe influence of coupling agents on the melt rheological properties of natural fiber composites has been investigated in this work using capillary and rotational rheometers. Scanning electron microscopy was also employed to supplement the rheological data. It was found that molecular weight and molecular weight distribution of the polymer matrix and coupling agent characteristics influence the filler wetting and the melt flow properties of the filled composites. Generally, low molecular weight and narrow molecular weight distribution polyethylene matrix provides relatively larger increase of the viscosity of the composites. Coupling agents tend to increase the resistance to shearing, but wall slip effects may interfere with the measured values, especially at very high filler loadings. Entrance pressure loss in capillaries is also influenced by polymer matrix and coupling agent used.magnified image

Influence of Fineness, Stiffness and Load-Displacement Characteristics of Natural Fibres on the Properties of Natural Fibre-Reinforced Polymers

The object of this study is the examination of micro-mechanical calculation models for the determination of stiffness and impact resistance of a fibre-reinforced epoxy-single-layer-composite. Cotton, ramie and man-made lyocell fibres were used in this work. In the calculation of the elasticity module it turned out that for ramie fibres there is a good consistency between theory and experiment. To correct the deviations caused by varying fibre characteristics correction factors were determined for cotton and lyocell fibres. Fibre characteristics are also of particular importance for the calculation of impact resistance. The adjustment required-particularly for cotton and lyocell fibres-was done by changing the relationship between debond length and critical fibre length. It was shown that it is basically possible to calculate the behaviour of natural fibre composites on the basis of precisely determined fibre properties.