Applied Mechanics and Materials Vol. 895

Abstract: Aluminium matrix composites offer improved damping properties than other metals and its alloy. Generally pure metals and its alloys may have fairly good mechanical properties but falls short in damping properties. Aluminium matrix composites are becoming important in aerospace automobile and marine applications due to its god damping properties. The present investigation is concerned with the damping capacity of iron oxide (Fe₂O₃) reinforced aluminium matrix composite. The composites were fabricated with 2%, 4% and 6%, by weight of iron oxide with varied particle of size 40 μm and 500 nm in equal proportions using stir casting process. From the results obtained the 500 nm size with 4 wt% of iron oxide showed improved dynamic properties. The iron oxides reinforced with aluminum matrix are found to be new substitutes for the existing materials with low damping properties.

Abstract: Aluminum-based metal matrix composites (MMCs) have been suggested due to intense interest from automobile, marine, aerospace and other structural applications owing to their balanced mechanical, physical and chemical properties. MMCs are manufactured in order to meet present demand such as low material density, high mechanical strength and higher wear resistance of the component. Generally,MMCs tend to form rougher surface during machining because of the abrasive nature of hard ceramic particles present in them. Stir casting technique was used for fabrication of this composite which ensures better homogeneity.Furthermore, an attempt has been made in this paper to examine the results on the surface roughness of Al-6082/SiC metal matrix composites (containing 0%, 5% and 10% SiC particles).Focus was spent on parametric optimization of these composites in order to achieve cost-effective machining limits. The machining parameter studies have been carried out through the design of experiments (DoE) under minimum quantity lubrication (MQL) condition and effect of machining parameters such as spindle speed, feed rate and depth of cut on surface roughness was investigated to analyze the influence of reinforcement on surface roughness. In addition, analysis of variance was studied to obtain percentage contribution of machining parameters involved. Also, the surface morphology of the machined surface was studied through a scanning electron microscope (SEM). Distribution of SiC in aluminum alloy is fairly uniform with few clusters. Results of the experiments revealed that most significant turning parameter for surface roughness was spindle speed followed by feed rate and depth of cut. Furthermore, an optimal setting parameter for getting lower surface roughness was presented in confirmation table.

Abstract: The survey primarily deals with the evaluation of green technology development in India. With the depletion of fossil fuels resources, increase of supply security issues, and menace of climate change; clean energy through green technology may offer the best possibilities and outlook for their long-term replacement. The United Nations designated the decade 2014–2024 as the “Decade of Sustainable Energy for All”. Achieving feasibility in energy employment is expected to create a cleaner environment, broader access to electricity, better energy efficiency, and result in greater investment in green technology. Clean energy initiative is not only to substitute the conventional source of energy, but for protecting the mother earth for the future mankind. Emblematic lantern and the oil lamp were the most prominent sources of light at nights for Indians when it achieved independence as it was suffering from severe electricity deficit. However scenario has changed after six decades. As per census 2011, out of 191.9 million household 107.2 million households were electrified. India is, however, aiming high in this domain, with a target to attain 175 GW of installed renewables capacity by 2022 which include 100 GW of solar, 60 GW of wind, 10 GW of bio power and 5 GW of small hydro-power. This survey has taken up to trace the research trends in India to fulfill the mission to almost substitute the conventional energy.

Abstract: India is a fastest growing major economy in 2018, with a growth rate of 7.4 per cent GDP. Energy use in developing countries like India has risen more than fourfold over the past three decades and is expected to continue increasing rapidly in the future. Energy is essential for a economical growth of any county. Biofuels derived from renewable resources will become a alternative supplement for the conventional energy sources in meeting the increasing requirements for transportation fuels. In the present paper, effort are made to evaluate the pongamia biodiesel of 20% Blend (PB20) with neat diesel as an alternative fuel for CI engine. The pongamia oil is converted into pongamia methyl esters (Biodiesel) using two step process Esterification and Transesterification. The fuel properties of raw pongamia methyl ester and blend (PB20) are evaluated as per ASTM/BIS standards to check their feasibility as an alternative fuel. The prepared blend is used to run the computerized CRDI diesel engine at different load conditions. From the experimental investigation made, PB20 has a potential to be as an alternative fuel for diesel engine. The performance of PB20 with respect to Brake Thermal Efficiency (BTHE), Mechanical Efficiency, Brake Mean Effective Pressure (BMEP) and Specific Fuel Consumption (SFC) is comparatively low when compared to neat diesel. The P-Ɵ and P-V diagram shows that the combustion of PB20 is as similar to that of neat diesel.

Abstract: Wire Electrical Discharge Machining (WEDM) is a specialized thermal machining process capable of accurately machining parts with varying hardness or complex shapes, which have sharp edges that are very difficult to be machined by the main stream machining processes. Selection of process parameters for obtaining higher cutting efficiency or accuracy in WEDM is still not fully solved, even with most up-to-date CNC wire EDM machine. It is widely recognised that Acoustic Emission (AE) is gaining ground as a monitoring method for health diagnosis on rotating machinery. The advantage of AE monitoring over vibration monitoring is that the AE monitoring can detect the growth of subsurface cracks whereas the vibration monitoring can detect defects only when they appear on the surface. This study outlines the optimization of titanium material using L₁₆ design of experiment. Each experiment has been performed varying the process parameters like pulse-on time, pulse-off time, current and bed speed. Among different process parameters voltage and flush rate were kept constant. Molybdenum wire having diameter of 0.18 mm was used as an electrode. Simple functional relationships between the parameters were plotted to arrive at possible information on Electrode Wear (EW) and AE signals. But these simpler methods of analysis did not provide any information about the status of the electrode. Thus, there is a requirement for more sophisticated methods that are capable of integrating information from the multiple sensors. Hence, method like Artificial Neural Network (ANN) has been applied for the estimation of EW, AE signal strength, AE count and AE RMS. The ANN algorithm is designed to learn the process by training the algorithm with the experimental data. The experimental observations are divided into three sets: the training set, validation set and testing set. The training set is used to make the ANN learn the process and the testing set will check the performance of ANN. Different models can be obtained by varying the percentage of data in the training set and the best model can be selected from these, viz., 50%, 60% and 70%. The best model is selected from the said percentages of data. Estimation of the EW and AE signals parameters by ANN at 70% of data training set showed the best correlation with the measured value.

Abstract: Magneto Rheological (MR) fluids are a class of smart materials where the shear stress is not directly proportional to rate of shear. The viscosity of fluid changes as magnetic field changes and hence this phenomenon is very useful in bearing-rotor system for attenuating the vibrations. In the present study the application of MR fluid as lubricant instead of Newtonian fluid in the journal bearing is explored through steady state, dynamic characteristics and stability. MR fluid film has been modeled as per Bingham rheological model. FEM with three node triangular elements has been used to solve the Reynolds equation both for the Newtonian fluid film and MR fluid film. The results show the load carrying capacity in the case of MR fluid journal bearing is higher than that of using the Newtonian fluid. The load carrying capacity increases with the increasing magnetic field for all eccentricity ratios. The results also show better stability of the bearing using MR fluid at higher eccentricity ratios. The unbalance response of the rotor mounted on the journal bearing using MR fluid is also estimated to be lower than that of with the Newtonian fluid.

Abstract: Spur gear is the most basic type of parallel-axis gear. In this study, contact stress and fatigue life of spur gear for different modules and for different materials were studied. The commercially available Solidworks 2016 is used for modelling and ANSYS Workbench tool for discretizing and solving. The analysis has been performed on the gear models of modules 1mm, 2mm and 3mm to observe the distribution of contact stress and life. The graphic results obtained were compared and it was found that contact stress decreases as the module increases and also aluminium alloy was having the least stress and high fatigue life among the selected materials. Hence from the finite element analysis, it’s found that the contact stress depends on the module and material used. Similarly fatigue life of gear purely depends on the material chosen.

Abstract: Waterlog due to urban flood is a great threat to the urban population now-a-days. An unplanned city with illegitimate constructions and without proper drainage planning has led to this problem. Problems associated with urban floods range from relatively localized incidents to major incidents, resulting in cities being inundated from a few hours to several days. Therefore, the impact can also be widespread, including temporary relocation of people, damage to civic amenities, deterioration of water quality and risk of epidemics. The study undertakes the waterlog problem of Jorhat town, Assam, India. The paper presents a System Dynamics approach based on the cause and effect analysis and feedback loop structures. Ten factors Rainfall, Water Log, Population, Urbanisation, Cost (health and economy), Waste Material Production, Drainage Construction and Maintenance, Encroachment, Ground Percolation and Drain Capacity are considered for the causal loop diagram. The model runs in Vensim PLE software and the simulated results suggest to construct the poorly developed drains of the town and to minimise drain blockage to mitigate water log for now and coming future.

Abstract: Silicone (SC) and polytetrafluroethylene (PTFE) reinforced polyoxymethylene (POM) composites have been fabricated by melt mixing followed by injection moulding. Physical and mechanical properties of SC and SC+PTFE/POM composites have been investigated as per ASTM standards. The dispersion of fillers in POM was studied by using scanning electron microscopy (SEM). The effects indicated that the hardness of the POM matrix decreases with increasing the SC content and slight increase in hardness was found in SC+PTFE/POM. The mechanical performance of the composites are investigated by means of a well known universal testing machine and notched Charpy impact tester. The POM with 10 wt. % of SC binary composite reveals good mechanical properties. The tensile and flexural properties of SC+PTFE/POM hybrid composites are higher than that of 20 and 30 wt. % SC reinforced POM binary composites. Further, these mechanical strength and impact toughness are established on the kind as nicely as filler loading over the full range of the study. The uniform dispersion of the filler in the POM matrix is obtained from SEM micrographs. Furthermore, SEM was used to identify the fractographic points of the tensile fractured POM based composites.

Abstract: Over the last decades composite materials, plastics and ceramics have been the dominant emerging materials. The volume and number of applications of composite materials have grown steadily, penetrating and conquering new markets relentlessly. So everybody is concentrating on new materials which will be strong enough, less weight, recyclable with reduced cost. Hence all the researchers are concentrated on the composite materials which have all the above properties. The present work is concentrated on coconut coir fiber and Rice husk reinforced polyester hybrid composites. The composites specimen was fabricated with various weight percentages of natural fibers namely coconut coir (20%, 15%, 10%, and 5%) and Rice husk (15%, 10%, and 5%) combined with CamElect 3321 resin using hand lay-up method. So to obtain new composite materials different proportions of coconut coir and Rice husk is added and the mechanical properties such as Tensile strength, Flexural Strength and Impact test were carried out for the samples cut from the fabricated composites specimen to the dimensions as per ASTM standard. With the increasing percentage of the reinforcements the performance of the material is improving. The tensile strength increases with the increase in coir reinforcement percentage and flexural strength increases with the increasing in percentage of the rice husk and the impact strength of the material gets boost with equal proportional percentage of coconut coir and rice husk reinforcement.