Hello Logout
 

Projects

NATURAL FIBER HYBRID COMPOSITES

Recently natural fibers have been receiving considerable attention as substitutes for synthetic fiber reinforcements such as glass in plastics due to their low cost, low density, acceptable specific strength, good thermal insulation properties, reduced tool wear, reduced thermal and respiratory irritation and renewable resources. The development of natural fiber usage in India has now reached an appreciable stage. The aim of this work is to develop a Natural Fiber Reinforced Hybrid Composite material with optimum properties so that it can replace the existing Synthetic Fiber Reinforced Hybrid Composite material for a suitable application. The concept of hybridization gives flexibility to the design engineer to tailor the material properties according to the requirements, which is one of the major advantages of the composites. Hybrid composites have long taken the attention of many researchers as a way to enhance mechanical properties of composites. However, hybrid composites using natural fibers are less studied. And in such studies, the hybrid composite often consists of one natural fiber and one non-natural fiber. Studies on hybrid composites with two natural fiber reinforcement phases are extremely rare. In this work, snake grass and coir fibers were used as the reinforcing material, since they are abundant in nature and have minimal effect on the environment because of their biodegradable properties. And also test its tensile, flexural, and impact strength and tensile, flexural, and impact modulus. Snake grass fiber is a member of cactus family and is extracted from the natural plant. It is made from the large spear shaped tropical leaves of the plant. It exhibits some better properties like durability, minimal wear and tear, better sound and impact absorbing properties, better resistance to moisture absorption, while coir fiber possesses high weather resistance due to higher lignin content. It also absorbs less water compared to other fibers due to lower cellulose content. It is the thickest and most resistant of all commercial natural fibres. Its cellular structure makes it more elastic than other natural fibres. Lignin is a natural polymer, which adds strength and elasticity to the cellulose based fiber walls. Hand layup technique was used to manufacture the composites. It is the oldest, simplest and most commonly used method for the manufacture of both small and large reinforced products. It is used in applications where production volume is low and other forms of production would be prohibitive because of costs or size equipment. Methyl Ethyl Ketone Peroxide, Cobalt Naphthalene were used as coupling agent and accelerator respectively. Volume fraction of the fibers was calculated using rule of mixtures and varied between 5% and 30% and the relative volume fraction was maintained as 1:1. A roller was used in order to maintain the homogeneity of the fibers within the composite. Curing time for the composite sheet was about 7 hours to 9 hours. Initially 10% and 20% volume fraction of composite sheets were manufactured and tested for its mechanical properties. An electronic Tensometer was used to determine the tensile strength and tensile modulus by conducting tensile test in it. Cutting of five Specimens according to the ASTM standard ASTM D 638 – 03 and tested. Curves were plotted for load against displacement and stress against the strain and tensile strength and tensile modulus were determined using the results obtained from Tensometer. For 10% volume fraction of the fibers the average maximum tensile strength of the specimen was found to be 22.31 MPa and the average maximum tensile modulus was found to be 453.78 GPa. Average peak load and average maximum displacement was found to be 535.5N and 2.33mm respectively. Similarly for 20% volume fraction the average maximum tensile strength was found to be 36.45MPa and the average maximum tensile modulus was 428.34GPa. Average peak load and average displacement was found to be 877.64N and 3.67mm respectively. Flexural strength and modulus were determined by conducting three point flexural tests according to the standard ASTM D 790 – 03. The test was carried out in a spring testing machine with a special attachment. Five specimens, each of rectangular shape, was prepared and tested. For 10% volume fraction of the fiber the average flexural strength was found to be 31.57 MPa and average flexural modulus was 6.39GPa. Average load applied and the deflection was found to be 62N and 21.5mm respectively. For 20% volume fraction of the fiber the average flexural strength was found to be 67.33 MPa and average flexural modulus was 5.28 GPa. Average load applied and the deflection was found to be 112N and 15.3mm respectively. Specimen for 5%, 15%, 25% and 30% volume fraction of the fibers are yet to be manufactured and tested for its tensile, flexural and impact properties. To analyze the failure cross section of the failed specimen Scanning Electron Microscope pictographs were used. Fiber pullout, delamination inferences are drawn for the tensile, flexural and impact tested specimen. A multi variable regression model is to be formed and it shows the relation between the strength and other factors like volume fraction of the fiber, fiber length and thickness of the composite specimen and the experimental results may be compared with the results obtained from the mathematical model.



Tags :
4
Your rating: None Average: 4 (2 votes)