Applied Mechanics and Materials Vols. 766-767

Abstract: Composite materials are preferred in all engineering applications, nowadays, because of their superior properties over the traditional materials. Among Composite materials, Natural fiber reinforced polymer finds rapid development in Industrial applications and many areas of research. The main advantageous features of these composites are Renewability, Biodegradability and low cost. They are less dense and also easily available. These Natural fibers replace synthetic fibers in many important applications like Automobiles, Aerospace, etc. This paper reviews the research work carried on different types of Natural fibers reinforced polymer along with their preparation and properties, especially Sisal and Banana fibers.

Abstract: In order characterize the outstanding performance of the three dimensional (3D) hybrid composites, the charpy and flexural test has been carried out. 3D fiber structures have been achieved by using hand lay-up process and machine stitching method. Materials for hand lay-up and machine stitching process were glass fiber, jute fiber, and epoxy resin and nylon fiber respectively. Two dimensional (2D) glass fiber composite and 2D hybrid composite with the same stacking sequence as three dimensional (3D) counterparts have also been fabricated for the comparison of impact and flexural strength. The impact strength of 3D hybrid composite was increased (5-10%) compared with that 2D glass fiber and 2D hybrid composites. The flexural strength and modulus of 3D hybrid composite were increased (5-10%) compared with that of 2D hybrid composites.

Abstract: Recent growth in the field of engineering demands specialised composite materials to meet various industrial needs. Composite materials are emerging as the most promising new materials. This paper deals with the fabrication and analysis of flexural characteristics of flax and Abaca hybrid epoxy composite. The show that GFRP + Flax +Abaca based hybrid composite has a higher ultimate stress which is much greater than GFRP + Flax composite and GFRP + Abaca composites. The inner filament breakage and crack propagation are studied using scanning electron microscope.

Abstract: The development of high-performance engineering products made from natural resources is increasing worldwide, due to renewable and environmental issues. Among the many different types of natural resources, kenaf plants have been extensively exploited over the past few years. Kenaf-glass fibers reinforced composites are manufactured by compression moulding and the tensile, flexural and impact tests are conducted. From the experiment it is found that the processing conditions have little effect on properties except for pressurization which increased tensile and flexural strength at low fiber volume fractions. Examinations using a scanning electron microscopy showed that all the laminates failed due to mechanical loading and the way of fracture of the materials.

Abstract: Natural Fiber Reinforced Composite (NFRC) are used by replacing Synthetic Fiber Reinforced Composites (SFRC) because of its poor reusability, recycling, bio degradability. Even though NFRC are lack in thermal stability, strength degradation, water absorption and poor impact properties. The hybridization and nanoparticles mixed in different polymers are used to improve mechanical and wear properties of the polymer composites. In the present investigation Multi wall carbon nanotubes (MWCNT) dispersed in Epoxy resin using ultrasonic bath sonicator are used as matrix face for hybrid banana-Glass Fiber Reinforced Plastics composite materials which is manufactured by compression molding processes. As per ASTM standards tensile, compression tests are carried out by using Universal Testing Machine. Microstructure of samples are investigated by scanning electron microscope (SEM) with Energy dispersive X-ray (EDS). SEM shows the homogeneous distribution of the fiber in the modified polymer matrix. The results indicated that the increase in weight % of MWCNT improves the mechanical properties of MWCNT filled hybrid natural fiber composites.

Abstract: An experimental analysis has been carried out to investigate the mechanical properties of composites reinforced by sisal, coir, and banana fibres into epoxy resin matrix. The natural fibres were extracted by retting and manual processes. The composites fabricated by epoxy resin and reinforcement in the hybrid combination of Sisal-Banana and Sisal-Coir with the volume fraction of fibres varying from 5% to 30%. It has been identified that the mechanical properties increase with the increase of volume fraction of fibres to a certain extent and then decreases. The hybridization of the reinforcement in the composite shows greater mechanical properties when compared to individual type of natural fibres reinforced. For all the composites tested, the tensile strength of the composite increased up to 25% of volume fraction of the fibres and further for the increase in the volume fraction of fibre the mechanical properties were decreased. As same as tensile properties, the flexural and impact strength also increased linearly up to 25% of volume fraction of fibres and further for the increase in the volume fraction of fibre the mechanical properties were slightly decreased. Key Words: Sisal, Banana, Coir, Epoxy, Hybrid composite.

Abstract: In these days, natural fiber and its composites are gaining more interest and utilization of biofibers has increased because of growing concern towards economic, environmental and conservation issues. The present study investigates, Fourier Transform Infra-red (FTIR) spectroscopy and chemical resistance properties on the coconut leaf sheath (CLS) reinforced Phenol Formaldehyde (PF) composites. Naturally woven coconut leaf sheath composites were prepared in both NaOH treated and untreated forms with volume fraction of 60% of sheath and 40% of Phenol Formaldehyde resin. CLS were chemically treated using 5% of NaOH and composite boards were made using a hydraulic hot press at 140°C. FTIR test was conducted for both treated and untreated CLS fiber composites. And it was found that, due to chemical treatment of fibers reduction in lignin and hemicellulose content was observed. The chemical resistance of alkali treated and untreated CLS composites were measured by chemical absorption and chemical thickness swelling methods. Treated and untreated composite samples were then placed in 1N of saline, Hcl, HNO₃ and H₂SO₄ separately. It is also observed that, saline and Hcl have been absorbed more in case of untreated composites and HNO₃and H₂SO₄ is absorbed more in treated composites. These tests were done to know that, these composites can be used in manufacturing products which gives better chemical resistance.

Abstract: With recent developments in technology and science, we have been depending heavily on synthetic materials for various applications. In the present work, jute, banana and glass fibers are reinforced with epoxy resin in alternative positioning and various probabilities at different post curing temperature to form sandwich type composites. The composite block was cured at room temperature for 24hrs. The cold cured composite block was then post cured at various post curing temperature of 30°C, 60°C, 90°C, 120°C, 150°C and 180°C and 3KPa pressure in the hot press for 10minutes. The tensile and flexural properties of the composites obtained at different post curing temperature were studied. The morphology of the tensile fracture was studied using scanning electron microscopy analysis.

Abstract: An attempt has been made to study the dry sliding wear behaviour of Aluminium based hybrid composites in room temperature.Al 2219 is used as base material with B₄C and MoS₂ as reinforcements. The hybrid composite were prepared by conventional stir casting technique. The dry sliding wear test were carried out for various parameters like sliding distance, applied load and sliding speed. The Optical Microscope and SEM results showed the presence of B₄C and MoS₂, which are fairly uniform and randomly dispersed on matrix material.XRD analysis, shown the presence of B₄C and MoS₂ phases in the prepared composites.The incorporation of reinforcement particles B₄C and MoS₂ reduces the specific wear rate of composites. The addition of MoS₂ as a secondary reinforcement has significant effect on reducing specific wear rate of prepared composites. By using SEM worn surface of hybrid composites were studied.

Abstract: This paper aims to understand the influence of sintering temperature on the drilling performance of Al 2219 – SiC_p composite. This type of composite is currently used in aerospace and transportation industries. Drilling is the most frequently employed operation of secondary machining owing to the need for fabrication. This composite is usually subjected to precipitation heat treatment and needs the study of influence of sintering temperature on machining performance. The composite is fabricated through powder metallurgy route. The drilling tests are conducted with PCD drill of 5 mm diameter and 118° point angle. The experiments are conducted under conditions of different spindle speeds of 500, 1000 and 1500 rpm and feed rates of 10, 15 and 20 mm/min. Specific cutting pressure and surface roughness of the hole are considered as performance indicators during the study. Weight fraction of the reinforcement and sintering temperature are found to have significant influence on the drilling performance of the composites.