Faculty Publications
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Item Dry sliding wear of epoxy/cenosphere syntactic foams(Elsevier Ltd, 2015) Manakari, V.; Parande, G.; Doddamani, M.; Gaitonde, V.N.; Siddhalingeshwar, I.G.; Kishore; Shunmugasamy, V.C.; Gupta, N.Abstract Dry sliding wear behavior of epoxy matrix syntactic foams filled with 20, 40 and 60 wt% fly ash cenosphere is reported based on response surface methodology. Empirical models are constructed and validated based on analysis of variance. Results show that syntactic foams have higher wear resistance than the matrix resin. Among the parameters studied, the applied normal load (F) had a prominent effect on wear rate, specific wear rate (ws) and coefficient of friction (?). With increasing F, the wear rate increased, whereas ws and ? decreased. With increase in filler content, the wear rate and ws decreased, while the ? increased. With increase in sliding velocity as well as sliding distance, the wear rate and ws show decreasing trends. Microscopy revealed broken cenospheres forming debris and extensive deformation marks on the wear surface. © 2015 Elsevier Ltd.Item Wear response of walnut-shell-reinforced epoxy composites(ASTM International, 2017) Doddamani, M.; Parande, G.; Manakari, V.; Siddhalingeshwar, I.G.; Gaitonde, V.N.; Gupta, N.Present work utilizes agricultural by-product, walnut shell, as reinforcing filler in epoxy matrix for investigating dry sliding wear behavior using a pin-on disc wear-testing machine. Effects of sliding velocity (0.5-1.5 m/s), normal load (10-50 N), sliding distance (1000-3000 m) and filler content (10-30 wt. %) on wear rate (Wt), specific wear rate (Ws) and coefficient of friction (?) are investigated. The experiments were planned as per design of the experiments scheme and the wear characteristics were analyzed through response surface modeling (RSM) method. The lowest Wt of 1.1 mm3/km was noted for 1.5 m/s sliding velocity with 30-wt. % filler content. Sliding distance did not have a significant influence on Ws above a critical load of 40 N. The minimum ? was observed at 1-m/s sliding velocity, 40-N load, 1000-m sliding distance, and 30-wt. % filler. Lower values of Wt and ? at higher walnut-shell loadings support feasibility of using such composites in wear-prone applications. The wear mechanism was determined in the composites using extensive scanning electron microscopic observations. © © 2017 by ASTM International.Item Influence of materials and machining parameters on drilling performance of syntactic foams(ASTM International, 2018) Ashrith, H.S.; Doddamani, M.; Gaitonde, V.N.; Gupta, N.The effects of drilling parameters and material properties are investigated on epoxy matrix syntactic foams reinforced with 20, 40, and 60 volume percent glass microballoon. The influences of cutting speed, feed, drill diameter, and filler content on drilling performance are studied based on the full factorial design of experiments using tungsten carbide twist drills. Based on experimental results, machinability aspects within the range of the chosen input parameters are predicted using response surface methodology-based models, which can guide industrial practitioners for choosing the appropriate process parameters. Microscopy is conducted on the drilled specimens to understand crack initiation and propagation mechanisms. The thrust force and specific cutting coefficient of syntactic foam are 40 % lower as compared to those of neat epoxy. The surface roughness of syntactic foams is higher than that of neat epoxy. The micrographs of drill bits show negligible tool wear. These results show the possibility of using syntactic foams in industrial applications in which the drilling of material is required for reasons such as joining using bolts. © © 2018 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959Item Effect of wall thickness and cutting parameters on drilling of glass microballoon/epoxy syntactic foam composites(Elsevier Ltd, 2019) Ashrith, H.S.; Doddamani, M.; Gaitonde, V.Effect of glass microballoon (GMB) wall thickness and cutting parameters (cutting speed, feed and drill diameter) on thrust force (Ft), surface roughness (Ra), specific cutting coefficient (Kf), cylindricity (CYL), circularity error (Ce-Exit) and damage factor (Fd-Exit) in drilling of GMB/epoxy syntactic foam is presented. CNC vertical machining centre is utilised for conducting experiments based on full factorial design. Significant process parameters are identified through response surface methodology. Wall thickness significantly affects the Ce-Exit and CYL of the drilled hole. Increasing wall thickness significantly reduces the Ra (30%), CYL (41%) and Ce-Exit (56%) due to the increased thermal stability of syntactic foams. This observation is very crucial for the syntactic foams used in structural applications pertaining to structural stability. Drill diameter is observed to be significant for Ft, Ra, CYL and Fd-Exit; while Kf is governed by feed. Furthermore, grey relation analysis (GRA) is used to identify the specific combination of process parameters to obtain good quality drilled hole. Combination of higher particle wall thickness and feed, lower cutting speed and drill diameter produces a sound hole quality as observed from GRA. Hole quality is highly influenced by drill diameter followed by cutting speed and GMB wall thickness. The present study offers guidelines for the industries (structural applications) to produce quality holes in GMB reinforced epoxy matrix. © 2018 Elsevier Ltd