Thirumaleshwara Bhat

Effect of Filler Content on the Performance of Epoxy/PTW Composites

This paper presents the mechanical and tribological characteristics of potassium titanate whisker (PTW) reinforced epoxy composites. The effect of various test variables and material parameters on the friction and wear behavior of epoxy/PTW composites has been studied systematically. Tribological tests were conducted on a pin-on-disc apparatus under dry sliding conditions. Addition of PTW was found to improve the wear resistance of the composites and 15 wt% PTW filled epoxy exhibited lowest specific wear rate and highest friction coefficient compared to other test samples. PTW additions showed beneficiary effect on density, hardness, and stiffness properties of composites; however, strength properties and ductility were found to decrease with the increasing content of PTW. Scanning electron microscope (SEM) images of tensile fractured surfaces and worn-out surfaces of selected samples revealed different fracture mechanisms.

Optimization of Dry Sliding Wear Performance of Ceramic Whisker Filled Epoxy Composites Using Taguchi Approach

This study evaluates the influence of independent parameters such as sliding velocity (A), normal load (B), filler content (C), and sliding distance (D) on wear performance of potassium-titanate-whiskers (PTW) reinforced epoxy composites using a statistical approach. The PTW were reinforced in epoxy resin to prepare whisker reinforced composites of different compositions using vacuum-assisted casting technique. Dry sliding wear tests were conducted using a standard pin on disc test setup following a well planned experimental schedule based on Taguchi’s orthogonal arrays. With the signal-to-noise (S/N) ratio and analysis of variance (ANOVA) optimal combination of parameters to minimize the wear rate was determined. It was found that inclusion of PTW has greatly improved the wear resistance property of the composites. Normal load was found to be the most significant factor affecting the wear rate followed by (C), (D), and (A). Interaction effects of various control parameters were less significant on wear rate of composites.

Effect of Cutting Parameters on Cutting Force and Surface Roughness of Aluminium Components using Face Milling Process - a Taguchi Approach

Aluminum is used excessively in the modern world and the uses of the metals are extremely diverse due to its many unusual combinations of properties. They have been widely used in industries, especially aerospace industries due to their attractive mechanical and chemical properties. However, machining of Aluminium results in good surface finish at the expense of tooling cost. This study investigates the optimum parameters that could produce significant good surface finish and optimum cutting force thereby reducing tooling cost. It employs the Taguchi design method to optimize the surface roughness quality and cutting force in a Computer Numerical Control (CNC). The milling parameters evaluated are cutting speed, feed rate and depth of cut. An L9(3 4 ) orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) are employed to analyze the effect of these cutting parameters. The analysis of the result indicates that the optimal combination for low resultant cutting force and good surface finish are high cutting speed, low feed rate and low depth of cut. The study shows that the Taguchi method is suitable to solve the machining problems with minimum number of trials as compared with a full factorial design.

Effect of potassium titanate whiskers on the performance of vacuum molded glass/epoxy composites

Effect of potassium titanate whiskers on the mechanical and tribological properties of glass/epoxy composite systems has been investigated experimentally. Composite laminates were prepared by hand lay-up technique followed by vacuum bagging by varying the percentage of potassium titanate whiskers addition. Mechanical properties of the developed composites were evaluated as per ASTM standards. Tribological tests were conducted under dry sliding conditions on a pin on disc test rig. The tests results indicated that addition of the potassium titanate whiskers has significant effect on the properties of glass/epoxy composites. Density, hardness, stiffness properties, friction coefficient and wear resistance of the composites were found to improve with the potassium titanate whiskers loading. However, strength properties of the glass epoxy composites were found to reduce with whisker content. The mode of failure after the tensile tests and worn surface of some selected samples were studied using scanning electron microscope.

Modeling and Analysis for Wear Performance in Dry Sliding of Epoxy/Glass/PTW Composites Using Full Factorial Techniques

The dry sliding friction and wear behavior of epoxy hybrid composites reinforced with glass fibers and a varying amount of potassium titanate whiskers (PTWs) fabricated by vacuum hand layup method were studied. The influence of normal load, sliding velocity, and whisker content on both friction coefficient and specific wear rate was investigated on a pin-on-disc machine. The tests were conducted at ambient conditions based on the 3 × 3 (3 factors at 3 levels) full factorial design. Analysis of variance (ANOVA) was performed to obtain the contribution of control parameters on friction coefficient and wear rate. The density and hardness of the composites were found to be enhanced with the PTW loading. The friction coefficient and wear resistance of the hybrid composites were found to be improved with the whisker content and were also greatly influenced by normal load and sliding velocity. A correlation between dry sliding wear behaviors of composites with wear parameters was obtained by multiple regressions. The worn out surface of selected samples was observed under scanning electron microscope (SEM) to identify wear mechanisms. This study revealed that the addition of the ceramic microfillers such as PTW improves the wear performance of the epoxy/glass polymer composites significantly.