Maximum tangential stress coupled with probabilistic aspect of fracture toughness of hybrid bio-composite

The statistical aspect of mode I, mode II and mixed mode I/II fracture toughness of epoxy based bio-composite reinforced with 20 wt% walnut shell particle and 10 wt% coconut fiber is studied. The bio-composite is fabricated by the squeeze casting method. A series of fracture tests are conducted on hybrid bio-composite using three point bend, four point bend and semicircular arc bend specimen. The statistical distribution of normalized geometry parameters, T stress, crack tip plastic zone size, particle and fiber size are studied. Generalized maximum tangential stress criterion is modified considering the stochastic nature of the geometry and strength parameters assuming them to follow two parameters Weibull probability distribution. The model developed is applied to the bio-composite and predicted results are compared with the experimental values. Very good agreement is found between the experimental results and predicted results. The variability in the fracture toughness values are correlated with the particle and fiber size determined from scanning electron microscopy. Keywords: Fiber, Hybrid, Fracture toughness, Statistical properties/method

Effect of rice husk (treated/untreated) and rice husk ash on fracture toughness of epoxy bio-composite

Present work studies the effect of particle reinforcement on fracture toughness of bio-composites. The filler used has been taken as rice husk. Epoxy resin has been taken as matrix material. Composites with varying filler loading of 10, 20, 30 and 40 wt.% were fabricated. The fracture toughness was seen to be increasing with increase in filler loading. However beyond 20% there was a decrease in fracture toughness with increase in filler loading. The effect of fibre treatment on toughness was also observed. Rice husk fibres pre-treated with NaOH were used. It was observed that fracture toughness further improved due to treatment. The increase in fracture toughness was significant. Fracture toughness increased from 1.072 to 2.7465 MPa√mm for 20% reinforcement and after treatment it increased to 2.876 MPa√mm. It was observed that concentration of treatment media also affects the fracture toughness. Further the effect of hybridization was observed by addition of rice husk ash as a secondary reinforcement. The fracture toughness of the resulting composites was remarkably higher than that of pure epoxy

Rice husk as a fibre in composites: A review

In the last decade due to ever growing environmental concerns, use of natural fibres as fibre materials has gained momentum and acceptance. Natural fibres provide advantage of being economical and environment friendly at the same time. Rice husk, an agricultural waste is being utilized as a natural fibre for development of bio-composites. Present paper attempts to understand the applicability of rice husk as a fibre with various polymers based on the recent research works. It also throws light on various modification techniques that can further enhance the associated mechanical properties by altering the chemical and physical properties of husk. The paper may assist in understanding the phenomenon associated in manufacture of rice husk based bio-composite and provide a critical insight to the future applications of rice husk

Mechanical characterization and machining performance evaluation of rice husk/epoxy an agricultural waste based composite material

Natural fibers from agricultural waste have received more attraction than traditional synthetic fibers in recent years. In present investigation epoxy/rice husk composite has been fabricated to utilize the agricultural waste which can be recycled easily and overcome the pollution problems due to smoke and fine silica ash. Study of interfacial bonding and dispersion of rice husk in epoxy resin has been studied through scanning electron microscope image. Characterization of fabricated composites has been done by mechanical properties. Ultimate tensile strength, Young’s Modulus and hardness are highest at 10 wt.% of rice husk particle and their values are 66.5 MPa, 616.46 MPa and 16.8 HV respectively. Machinability of epoxy/rice husk composites has been determined through drilling operation. Effect of feed rate (0.1, 0.2 and 0.3 mm/rev), speed (300, 600 and 900 rpm) and wt.% of reinforcement (10, 15 & 20) have been studied on machinability of epoxy/rice husk composites. Taguchi L27 orthogonal array has been applied to conduct the experiments to evaluate the performance characteristics viz thrust force and torque. Weight percentage was found the most significant factor for machinability followed by feed rate and speed