S. Rajendra Boopathy

Delamination Analysis in Drilling of CFRP Composites Using Response Surface Methodology

Carbon fiber reinforced plastic (CFRP) composite materials are finding increased applications in many industries due to their excellent properties. Drilling of CFRP composites is needed for joining of these composite structures. During drilling, delamination is an important factor, which affects the property of the drilled hole. In this work experiments are conducted to analyze the delamination in drilling of CFRP composites. The cutting parameters considered are spindle speed, feed rate, and drill diameter. The tool material used for the present investigation is ‘‘BRAD and SPUR’’ type made of carbide. Second-order mathematical relation is established using response surface methodology for predicting delamination in drilling of CFRP composites. The results indicate that the model can be effectively used to predict the delamination in drilling of CFRP composites. The effect of different parameters in drilling of CFRP composites is analyzed and presented in detail.

Microstructure and tensile properties of friction stir welded dissimilar AA6061–AA5086 aluminium alloy joints

Abstract The fusion welding of dissimilar heat treatable and non-heat treatable aluminium alloy faced many problems related to solidification. The difficulties can be overcome to achieve the combined beneficial properties of both aluminium alloys using friction stir welding (FSW). The microstructural features and tensile properties of friction stir welded (FSW) similar and dissimilar joints made of AA6061 and AA5086 aluminium alloys were investigated. The microstructures of various regions were observed and analyzed by means of optical and scanning electron microscopy. Microhardness was measured at various zones of the welded joints. The tensile properties of the joints were evaluated and correlated with the microstructural features and microhardness values. The dissimilar joint exhibits a maximum hardness of HV 115 and a joint efficiency of 56%. This was attributed to the defect free stir zone formation and grain size strengthening.

Corrosion behaviour of friction stir welded AZ61A magnesium alloy welds immersed in NaCl solutions

Abstract The extruded AZ61A magnesium alloy plates of 6 mm thickness were butt welded using friction stir welding (FSW) process. The corrosion behavior of the welds was evaluated by conducting immersion test in NaCl solution at different pH value, immersion time and chloride ion concentrations. An empirical relationship was established incorporating pH value, immersion time and chloride ion concentration to predict the corrosion rate of friction stir welds of AZ61A magnesium alloy at 95% confidence level. Three-factor, five-level central composite rotatable design was used to minimize the number of experimental conditions. Response surface method was used to develop the relationship. The results show that the corrosion resistance of AZ61A magnesium alloy welds in the alkaline solution is better than that in the acidic and neutral solutions, moreover, low corrosion rate is found at low concentrated solution and longer exposure time, and the corrosion morphology is predominantly influenced by the distribution of β-phase.

Fabrication and Evaluation of Tensile Properties of Kenaf-Flax Hybrid Composite

With the upcoming difficulties the need for environmental friendly, biodegradable material plays vital role in automotive and aero space applications. This necessitates to innovate new materials like composites and smart materials. In this paper, the Flax and Kenaf fibres are used as reinforcement to form hybrid composite. The tensile properties of hybrid composites are compared with single fibre composites. The result shows hybridization have more impact on enhanced tensile property. Hand layup technique is used in this work to prepare composite specimens. Fiber distributions,crack propagation and shearing styles analysed using the Scanning electron Microscope (SEM) images of the tested specimens.

Comparison of the Wear Properties of Polymer Composites Having CNT With and Without Glass Fiber Reinforcement

The adoption of light weight and high performance polymer matrix composites are needed for industries related to aerospace, automotive, consumer goods, etc. Polymer fiber reinforced composite material have very good desirable mechanical and thermal properties like low density, higher specific stiffness with high specific strength and a controlled co-efficient of thermal expansion with dimensional stability. The addition of carbon nanoparticle in these composites improved mechanical as well as wear properties of the material, which leads to more applications of these composites in various fields. In the present investigation carbon nanotube addition along with the glass fiber reinforced composite material was used as work material. The sliding wear tests were carried out on pin on disc wear tester. The tribological performance was studied by varying the applied load. The wear surfaces were analyzed by using scanning electron microscope, X-ray diffraction and energy-dispersive X-ray spectroscopy which are presented in detail.

Experimental Investigation of the Corrosion Behavior of Friction Stir Welded AZ61A Magnesium Alloy Welds under Salt Spray Corrosion Test and Galvanic Corrosion Test Using Response Surface Methodology

Extruded Mg alloy plates of 6 mm thick of AZ61A grade were butt welded using advanced welding process and friction stir welding (FSW) processes. The specimens were exposed to salt spray conditions and immersion conditions to characterize their corrosion rates on the effect of pH value, chloride ion concentration, and corrosion time. In addition, an attempt was made to develop an empirical relationship to predict the corrosion rate of FSW welds in salt spray corrosion test and galvanic corrosion test using design of experiments. The corrosion morphology and the pit morphology were analyzed by optical microscopy, and the corrosion products were examined using scanning electron microscope and X-ray diffraction analysis. From this research work, it is found that, in both corrosion tests, the corrosion rate decreases with the increase in pH value, the decrease in chloride ion concentration, and a higher corrosion time. The results show the usage of the magnesium alloy for best environments and suitable applications from the aforementioned conditions. Also, it is found that AZ61A magnesium alloy welds possess low-corrosion rate and higher-corrosion resistance in the galvanic corrosion test than in the salt spray corrosion test.

Modeling and analysis of roundness error in friction drilling of aluminum silicon carbide metal matrix composite

Friction drilling is a newer nontraditional hole-making chipless process, which is used to make holes in materials that are used in aerospace, automotive, commercial and industrial products, electronic packaging, and thermal management. In friction drilling, a rotating conical tool is applied to penetrate work-material and create a hole in single step. In this study, comprehensive analysis on friction drilling of Al/SiCp metal matrix composites is carried out. This article discusses the roundness (hole diameter accuracy) errors on dry friction-drilled holes. The parameters considered for the experiment are: the composition of workpiece, workpiece thickness, spindle speed, and feed rate. The effect of parameters on roundness errors is analyzed using experimental design matrix and empirical relation between the process parameters and roundness error is established using response surface methodology. Analysis of variance is used for analyzing the results. The influences of individual input process parameters on roundness error are analyzed and presented in this study.

Parameter optimization for the effective operation of hydrocarbon based Polymer Electrolyte Membrane for Fuel Cells

Sulfonated polystyrene ethylene butylene polystyrene (SPSEBS) membrane was prepared by evaporation casting method and was used as the Polymer Electrolyte Membrane (PEM) for PEM Fuel Cells (PEMFC). Suitability of the membrane for fuel cell studies was examined. This work analyses the optimization of operating parameters of the fuel cells such as cell temperature, flow rate and humidification temperature of anode gas (H2). Using Design of Experiments (DOE) number of trials to be conducted was identified. The parameters were optimised using the Taguchi method. The optimized value was then employed in the fuel cell setup and the cell performance was studied. The maximum fuel cell output was obtained at cell temperature of 70° C, flow rate of 0.4 lpm and humidification temperature of 70° C.

Studies on the corrosion characteristics of friction stir welded AZ61A magnesium alloy welds under immersion tests and potentiodynamic polarisation tests: a comparative evaluation

Extruded Mg alloy plates of 6 mm thick of AZ61A grade were butt welded using friction stir welding (FSW) process. The experimental techniques used in this investigation include immersion studies and potentiodynamic polarisation tests. The specimens were exposed to immersion and polarisation environments in order to evaluate their corrosion rates. Additionally, an attempt was made to develop an empirical relationship to predict the corrosion rate of the FSW joints in immersion tests and polarisation tests using response surface methodology. The developed relationship can be effectively used to predict the corrosion rate of friction stir welded AZ61A magnesium alloy at 95% confidence level for both the test conditions. This research work proves a better corrosion resistance of AZ61A magnesium alloy welds at the alkaline solution than the acidic and the neutral solutions, moreover, low corrosion rate was found at low concentrated solution and higher exposure time respectively.

Fabrication and friction drilling of aluminum silicon carbide metal matrix composite

This study investigates the friction drilling process, a nontraditional hole-making technique, for thermal aspects, energy and power in friction drilling of aluminum silicon carbide metal matrix composites (AlSiC MMC). This type of MMC is finding applications in making automotive pats like Engine, brake system and drive shaft. In friction drilling, a rotating conical tool is applied to penetrate work-material and create a hole in single step. The main concern in the present study is the effectiveness and advantages of this novel technique on dry friction drilled holes. The parameters considered are the composition of work piece, temperature of work piece, work piece thickness, spindle speed, and feed rate. The interaction effect of these parameters was analyzed using design of experiments applied response surface methodology. The AlSiC MMC plates were fabricated by liquid metallurgy method which is an economical and efficient one. A low volume low cost fabrication technique is adopted. Friction drilling process is compared with the conventional twist drilling process.