Fibre-reinforced composites are rapidly gaining market share in structural applications, but further growth is limited by their lack of toughness. Fibre hybridisation is a promising strategy to toughen composite materials. By combining two or more fibre types, these hybrid composites offer a better balance in mechanical properties than non-hybrid composites. Predicting their mechanical properties is challenging due to the synergistic effects between both fibres. This review aims to explain basic mechanisms of these hybrid effects and describes the state-of-the-art models to predict them. An overview of the tensile, flexural, impact and fatigue properties of hybrid composites is presented to aid in optimal design of hybrid composites. Finally, some current trends in fibre hybridisation, such as pseudo-ductility, are described.

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Fibre hybridisation in polymer composites: a review

Impacts of additives on performance and emission characteristics of diesel engines during steady state operation

State of the art on tribological behavior of polymer matrix composites reinforced with natural fibers in the green materials world

Hybrid composites are manufactured by combining two or more fibers in a single matrix. Hybrid composites can be made from artificial fibers, natural fibers and with a combination of both artificial and natural fibers. Hybrid composites can help us to achieve a better combination of properties than fiber reinforced composites. The constituent fibers in a hybrid composite can be altered in a number of ways leading to variation in its properties. The importance of this review can be attributed to the significant aspects of natural fiber based hybrid composites which are found to be predominantly affected by factors which include variation in fiber volume/weight fraction, variation in stacking sequence of fiber layers, fiber treatment and environmental conditions.

A review on mechanical behavior of natural fiber based hybrid composites

The natural fiber-reinforced polymer composite materials offered extensive range of properties which are suitable for large number of engineering application. The natural fibers have been abundantl...

Characterization of natural fiber and composites – A review:

Machining of composite materials is an important and current topic in modern researches on manufacturing processes. Determination of optimal cutting parameters is one of the most important elements in the machinability study of composites. Optimization has significant practical importance particularly for operating the machineries. In order to increase the accuracy of drill holes, the tool must be in good condition always as much as possible. To achieve good condition of tool, the optimization of machining parameters like drill bit diameter, spindle speed, and feed rate are mandatory. The objective of this paper is to study the effect of these process parameters on thrust force, torque, and tool wear in drilling of coir fiber-reinforced composites. The optimal settings of the parameters were determined through experiments planned, conducted, and analyzed using the Box–Behnken design, Nelder–Mead, and genetic algorithm methods. This paper also aimed to increase the cutting condition of tool, i.e., minimization of tool wear by applying the optimized input parameters using Nelder–Mead and genetic algorithm techniques.

Optimization of thrust force, torque, and tool wear in drilling of coir fiber-reinforced composites using Nelder-Mead and genetic algorithm methods

An investigation has been carried out to make use of coir, a natural fibre abundantly available in India. Coir-polyester composites were prepared and their mechanical and machinability characteristics were studied. The short coir-fibre-reinforced composites exhibited the tensile, flexural and impact strength of 16·1709 MPa, 29·2611 MPa and 46·1740 J/m, respectively. The regression equations were developed and optimized for studying drilling characteristics of coir-polyester composites using the Taguchi approach. A drill bit diameter of 6 mm, spindle speed of 600 rpm and feed rate of 0·3 mm/rev gave the minimum value of thrust force, torque and tool wear in drilling analysis.

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Drilling analysis of coir-fibre-reinforced polyester composites

The green husk coir fibres were treated with different levels of soaking time and concentration of alkali solution. As a result of alkali treatment, the surface modifications were done on the fibre surface and were studied using scanning electron micrographs. The coir–polyester composites were fabricated using hand lay up process and the mechanical properties (tensile, flexural and impact strength) were evaluated as per ASTM standards. The effect of soaking time and concentration of NaOH solution were studied based on evaluated values of mechanical properties to find out optimum fibre treatment parameters.

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Effect of soaking time and concentration of NaOH solution on mechanical properties of coir–polyester composites

Polymer-based composite materials posses superior properties such as high strength-to-weight ratio, stiffness-to-weight ratio, and good corrosive resistance and therefore, are preferred for high-performance applications such as in the aerospace, defense, and sport goods industries. Drilling is one of the indispensable methods for building products with composite panels. In this present work, an investigation has been carried out to evaluate mechanical and machinability characteristics of hybrid composites, E-glass, and natural coir fiber abundantly available in India. A regression model is developed for correlating the interactions of some drilling parameters such as drill bit diameter, spindle speed and feed rate, and their effects on responses such as thrust force, torque, and tool wear during drilling of glass-coir fiber reinforced hybrid composites by Design of Experiment techniques. Results indicated that feed rate is playing major role on the responses than other two variables.

Regression modeling and optimization of machinability behavior of glass-coir-polyester hybrid composite using factorial design methodology

Presently plastics are major contributors in solid waste which has higher thermal energy. Waste plastics can be converted into alternate fuel by pyrolysis which can replace diesel in compression ignition engines. The present study deals with the performance, combustion and emission characteristics of variable compression ratio engine fuelled with plastic oil, diesel and its blends with diethyl ether as an additive. Three blends 2.5, 7.5 and 12.5 % were tested in variable compression ratio engine. Waste plastic oil blend, pure plastic oil and diesel were considered for comparison. This study reveals that brake thermal efficiency increases for all the blends when compression ratio increases from 12 to 20. The specific fuel consumption of the blends and plastic oil were higher than the diesel. But the brake thermal efficiency for all the blends, plastic oil was comparatively lower than that of diesel. The regulated emissions of the variable compression ratio engine under varying loads and compression ratio for different blends were discussed.

S. Jayabal

Papers

Optimization of thrust force, torque, and tool wear in drilling of coir fiber-reinforced composites using Nelder-Mead and genetic algorithm methods

Drilling analysis of coir-fibre-reinforced polyester composites

Effect of soaking time and concentration of NaOH solution on mechanical properties of coir–polyester composites

Regression modeling and optimization of machinability behavior of glass-coir-polyester hybrid composite using factorial design methodology

Investigation on performance, emission and combustion characteristics of variable compression engine fuelled with diesel, waste plastics oil blends