In the present work, parameters for adapting the behavior of the uniaxial three-element viscoelastic constitutive model with integer and fractional index derivatives to the mechanical evolution of an epoxy-composite material reinforced with long random henequen fibers, were determined. Cyclic loading–unloading with 0.1%, 0.2%, 0.3%, …, 1.0% controlled strain and staggered fluency experiments at 5 MPa, 10 MPa, and 15 MPa constant tension were performed in stages, and the obtained data were used to determine and validate the model’s parameter values. The Inverse Method of Identification was used to calculate the parameters, and the Particle Swarm Optimization (PSO) method was employed to achieve minimization of the error function. A comparison between the simulated uniaxial results and the experimental data is demonstrated graphically. There exists a strong dependence between properties of the composite and the fiber content (0 wt%, 9 wt%, 14 wt%, 22 wt%, and 28 wt% weight percentage fiber/matrix), and therefore also of the model parameter values. Both uniaxial models follow the viscoelastic behavior of the material and the fractional index version presents the best accuracy. The latter method was noted to be adequate for determination of the aforementioned constants using non-large experimental data and procedures that are easy to implement.

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Parameter Identification of Fractional Index Viscoelastic Model for Vegetable-Fiber Reinforced Composite

Abstract The environmental awareness and sustainable nature of plant-based fibers have forced material researchers and automakers to use natural fibers instead of petroleum-based fibers for various industrial applications. The need for environmentally and biodegradable fibers has created a demand in the transportation industry. In this study, bio castor seed shell (C), glass fiber (G), and SiC (SC) fillers in a constant weight fraction (10 %) were reinforced separately with varying weight fractions (5–25 %) of African teff and snake grass fibers to improve the mechanical properties of the hybrid composites. Both African teff and snake grass fibers were subjected to alkaline treatment to remove amorphous elements such as hemicellulose, lignin, and wax, resulting in high surface roughness. The hybrid composites were fabricated by the compression molding technique and their mechanical properties were characterized as per ASTM standards. The fractured surface of the treated fiber was examined by scanning electron microscopy. From the results, it was found that SC10SG20AT showed maximum mechanical properties compared to C10SG20AT and G10SG20AT due to higher load-bearing capacity of SiC filler. Therefore, SC10SG20AT can be recommended for lightweight applications.

A comparative study on the mechanical properties of African teff and snake grass fiber-reinforced hybrid composites: effect of bio castor seed shell/glass/SiC fillers

Now- a- days the polymers are frequently used in domestic and industrial purposes. The properties of polymer composites are somewhat inferior and may be improved with the addition of filler and fiber materials. Jute is one of most economical natural fibres and is obtained primarily from plant materials such as cellulose and Lignin. Sisal is a vegetable, natural, fully biodegradable fibre and which has good specific strength and stiffness and is used for making ropes and twines. The banana fibre is the strongest natural fibres and is made from the stem of the banana tree which. exhibits good tensile strength and incredibly durable and bio-degradable. An attempt is made to improve the properties of polymer composites using jute, sisal and banana fibers and addition of 2 % titanium di boride as filler material. The polymer composites were made by hand layup method with epoxy as matrix material. The mechanical properties of fabricated composites such as tensile and impact strength, hardness were evaluated as per ASTM standards. It is found that tensile strength, hardness and impact strength were improved with the addition of fibers and filler material. The micro structural evaluation is also carried out using scanning electron microscope and found that particles were dispersed in the matrix material.

Rao D. Santha

Papers

Evaluation of Mechanical and Micro Structural Properties of Natural Fiber Reinforced Polymer Composites