44 research outputs found
Investigations on Machining Characteristics of Metal Matrix Composites Using Abrasive Flow Machining
No full textIn the era of non traditional finishing processes, it is of upmost importance that these processes can be applied to composite materials, as they have replaced traditional materials in many applications. It is hard to finish small slots in composite materials which have wide applications now days in aerospace, automobile, medical industries etc. Composite materials have replaced the traditional materials as their properties like light weight, good strength and good economy are of unique benefits. Abrasive Flow Machining (AFM) is an advanced finishing process suitable for machining difficult to reach and machine surfaces. In the literature, work has been reported on Abrasive Flow Machining of materials like Aluminium, Brass and EN8, etc. In the present work AFM set up has been designed and developed in the laboratory for experimental work. Composite materials with a high percentage of SiC (like 20-60 % SiC in Al/SiC composites) have been machined using abrasive flow finishing. Taguchi methodology is applied to find the effect of input parameters (Fluid pressure, percentage of oil in media, grit size, concentration of abrasives, work piece material and number of cycles) on the material removal rate (MRR), change in surface roughness (ΔRa) and surface topography. L27 array has been designed for experimental work. It is observed that extrusion pressure is the most significant factor for MRR and ΔRa. Optimization of response parameters (MRR and ΔRa) is done using Taguchi method. Further Response Surface Methodology (RSM) is also applied for experimental investigation. Box-Behnken design has been selected. Response parameters have been optimized using the desirability approach. The significance of different parameters is identified using ANOVA. An optimum combination of parameters is designed for the process. Mathematical modeling has been done for material removal rate using FEM and mechanism of material removal in abrasive flow machining has been also discussed. Specimens were examined and analyzed using scanning electron microscope and X- ray diffraction techniques. Work pieces cut by EDM process were finished by AFM process. It was observed that abrasive flow machining has removed the defects and improved the surface finish significantly
Development of efficient model updating technique using multi-stage response surfaces and derringer's function
No full textNovel Dynamic Model Updating Technique for Damped Mechanical System
No full textAbstract
Response surface method and Derringer’s function approach have been combined together to develop novel structural dynamic model updating technique for a damped mechanical system. Response surface models have been incorporated instead of finite element models, in order to increase computational efficiency of proposed technique. Derringer’s function approach is useful in dealing successfully with multi-objective optimization type model updating problems. Few such undamped techniques have been recently developed for undamped mechanical systems by combining the benefits of response models with Derringer’s function approach. This paper presents the theory and numerical application of a damped updating technique, which is based upon response models and Derringer’s function approach. In this technique, updating process is formulated as an optimization problem, wherein desirability functions are formulated, based on natural frequencies, modal-assurance-criterion values, resonance and anti-resonance points of frequency response functions. Desirability functions are then optimized to evaluate updated elastic parameters in stage one and updated damping constants in stage two of proposed technique. By using this technique, total absolute errors in natural frequencies, modal-assurance-criterion values, elastic parameters and frequency response functions have been reduced to 0.02%, 0.00%, 3.69% and 0.11%, respectively.</jats:p
Rheological Characterization and Finishing Performance Evaluation of Vegetable Oil-Based Bi-dispersed Magnetorheological Finishing Fluid
No full textModeling of Process Parameters for Surface Roughness and Analysis of Machined Surface in WEDM of Al/SiC-MMC
No full textEffects of Different Parameters on Delamination Factor of Glass Fiber Reinforced Plastic (GFRP)
No full textRole of Powder in the Machining of Al-10%Sic<sub>p</sub> Metal Matrix Composites by Powder Mixed Electric Discharge Machining
No full text This article reports the results of an experimental study conducted with the objective to understand the mechanism of material removal (role of silicon powder) in powder mixed electric discharge machining (PMEDM) while machining the Al-10%SiCP metal matrix composites. PMEDM is relatively a new development in the direction of enhancement of process capabilities of EDM. A new experimental set-up has been developed in the laboratory for experimentation. This research points out how the suspended powder helps in improving the performance of EDM. Further, the effect of the suspended powder and other selected parameters on process performance (machining rate (MR) and surface roughness (SR)) and subsequent optimal settings of the variables have been obtained using Taguchi method. The obtained experimental results indicate significantly improved performance of PMEDM over EDM. The appropriate addition of silicon powder into the dielectric fluid of EDM increases the MR and decreases the SR. The experimental results further indicate that the powder concentration, peak current, and pulse duration are the significant variables, while the supply voltage is an insignificant variable. The results were verified by conducting confirmation experiments with optimal process conditions. </jats:p
