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R Gnanamoorthy
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R Gnanamoorthy
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R Gnanamoorthy
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Gnanamoorthy, Rajappa
Gnanamoorthy, R.
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8 results
Now showing 1 - 8 of 8
- PublicationFretting Wear Behavior of Laser Peened Ti-6Al-4V(01-09-2012)
;Kumar, S. Anand ;Sundar, R.; ;Kumar, H.; ;Kaul, R. ;Ranganathan, K. ;Oak, S. M.Kukreja, L. M.This work deals with the influence of laser peening on the fretting wear behavior of Ti-6Al-4V. Laser peening was carried out on Ti-6Al-4V. The laser-peened surface was characterized by transmission electron microscopy. Surface roughness, nanoindentation hardness, residual stress, and tensile properties of the material in both laser-peened and unpeened conditions were determined. Fretting wear tests were conducted at different normal loads using a ball-on-flat contact geometry. Laser peening resulted in the formation of nanocrystallites on the surface and near-surface regions, increased hardness, and compressive residual stress. Laser peening did not affect the tensile properties and surface roughness significantly. There was no considerable difference between the values of the tangential force coefficient of laser-peened and unpeened samples. The fretting scar size, wear volume, and wear rate of laser-peened specimens were lower than those of unpeened samples. This may be attributed to an increase in surface hardness due to strain hardening and grain refinement at the surface and near-surface regions, higher compressive residual stress, and higher resistance to plastic deformation of laser-peened samples. © 2012 Copyright Taylor and Francis Group, LLC. - PublicationContamination assessment in metal foam flow field-based proton exchange membrane fuel cell(08-02-2022)
;Venkatesh, Gangisetty; Okazaki, MasakazuThe relative slippage between the open-cell metal foam flow fields and other parts in a fuel cell due to vehicular and flow-induced vibrations causes fretting. The material degradation due to fretting in nickel struts contaminate the stack and is investigated using simulated experiments. The as-formed strut surfaces are rough and increases the material loss during fretting. The total wear volume associated with a single contact in 22,000 cycles is 4.66 E−04 mm3. The contamination in the stack is estimated assuming a dodecahedron unit cell geometry and neglecting the fretting corrosion. About 47 g of debris is expected to be generated when an 8 ppi nickel foam flow fields used in a 50-cell stack for 8700 hours of operation. In addition, the generated flake shaped debris (<10 μm) can obstruct the flow of gases by clogging the gas diffusion layer. The proposed contamination estimation methodology will aid in performance prediction during service. - PublicationFretting wear studies on diamond-like carbon coated Ti-6Al-4V(25-01-2009)
;Navaneethakrishnan, P.; ;Pathak, S. D.; Ravi, N.This work is concerned with the performance of diamond-like carbon (DLC) coated Ti-6Al-4V flat samples fretted against alumina ball in two environments-ambient air and simulated body fluid (Ringer solution). Hydrogenated DLC (H-DLC) coatings were prepared by radio frequency plasma enhanced chemical vapour deposition process. Raman scattering measurements were done on the coatings. Fretting wear tests were conducted at different normal loads using a fretting wear test rig working on scotch yoke mechanism. Wear scars on the tested specimens were observed using an optical microscope. Wear volume was calculated based on wear scar diameter measured along parallel and perpendicular to the fretting direction. Tangential force coefficient (TFC) values exhibited by DLC coated samples were lower than those exhibited by uncoated specimens in both ambient air and Ringer solution. Very low TFC values and low wear volume were observed for H-DLC coated samples tested in air at lower loads of 1.9 N and 4.9 N. It was attributed to occurrence of graphitisation and formation of transfer layer on alumina ball. © 2008 Elsevier B.V. All rights reserved. - PublicationEffect of hardness on fretting wear behaviour of structural steel, En 24, against bearing steel, En 31(01-01-2007)
;Ramesh, R.Fretting wear damage is frequently reported in the races of rolling element bearings and leads to the increased noise and vibration in the total machinery. The fretting wear studies were conducted on the as-received and hardened and tempered En 24 steel fretted against hardened and tempered bearing steel, En 31. Tests were conducted at different normal loads under unlubricated dry conditions. The coefficient of friction depends on the contact conditions, whether it is gross slip or stick slip. Hardness has only marginal effect on improving the fretting wear resistance. © 2006. - PublicationInfluence of counterbody material on fretting wear behaviour of surface mechanical attrition treated Ti-6Al-4V(01-01-2013)
;Anand Kumar, S.; ;Sankara Narayanan, T. S.N.Surface mechanical attrition treatment (SMAT) was carried out on Ti-6Al-4V. Fretting wear tests were conducted using two counterbody materials (alumina and steel). SMAT resulted in surface nanocrystallization. Due to high hardness, low tangential force coefcient (TFC) and more TiO 2 layer, fretting wear resistance of SMAT treated samples was higher than that of the untreated samples. TFC values obtained with alumina counterbody were higher than those obtained with steel counterbody. The fretting wear resistance of untreated and treated samples fretted against alumina was lower than that of the samples fretted against steel due to tribochemical reactions at the contact zone. © 2012 Elsevier Ltd. - PublicationFretting wear behavior of fine grain structured aluminium alloy formed by oil jet peening process under dry sliding condition(30-07-2012)
;Arun Prakash, N.; Use of aluminium alloy in aerospace and automotive industry has increased due to their high strength to weight ratio. Oil jet peening, a surface modification process is developed to impart compressive residual stresses on the surface of the metallic materials and resulted in significant surface hardening with associated grain refinement. Unlubricated fretting tests were performed on the oil jet peened and unpeened aluminium samples using ball-on-flat configuration at constant slip amplitude and at different applied normal loads. At low applied normal loads, the contact region between the mating surfaces makes the asperities interlock each other resulting in high tangential force coefficient. Due to micro-displacement between the interfaces of two mating members, cracks initiate and cause debris formation. The steady state tangential force coefficient, wear volume and specific wear rate of the oil jet peened samples were lower than those of the unpeened (as-received) samples for all the conditions tested and this is mainly attributed to increased substrate strength. A complex adhesion and oxidation type of wear mechanism was observed at low applied normal loads and at high applied normal loads abrasion was found to be a dominant wear mechanism. © 2012 Elsevier B.V. - PublicationInfluence of counterbody material on fretting wear behaviour of uncoated and diamond-like carbon-coated Ti-6Al-4V(01-03-2009)
; ;Navaneethakrishnan, P.Fretting wear tests were carried out at different normal loads on uncoated and diamond-like carbon (DLC)-coated Ti-6Al-4V samples against two counterbody materials: alumina and ultra high molecular weight polyethylene (UHMWPE). Tangential force coefficient (TFC) values obtained with alumina counterbody were much higher than those obtained with UHMWPE. A significant reduction in TFC was noticed in DLC-coated samples compared with uncoated specimens when tested against alumina counterbody at normal loads of 1.96 and 9.8 N. There was not much difference betweenTFC values of DLC-coated and uncoated specimens when tested against UHMWPE counterbody. DLC-coating reduced specific wear rate significantly at 1.96 N when the sample was tested against alumina counterbody. However, at higher loads, both uncoated and DLC-coated samples exhibited similar specific wear rates. As initial maximum contact pressure was relatively very low, no fretting scar was observed both in uncoated and DLC-coated samples tested against UHMWPE counterbody. © IMechE 2009. - PublicationFretting wear behaviour of 304 stainless steel fretted against different counterbody materials(01-12-2013)
;Kumar, S. A. ;Sai, S. K.; Effect of counterbody material on fretting wear resistance of 304 stainless steel is investigated in the present study. Fretting wear experiments were carried out at different normal loads on 304 stainless steel samples for 25 000 cycles using four different counterbody materials (alumina, SAE 52100 steel, 304 stainless steel and Ti-6Al-4V). At different normal loads, different fretting regimes were observed: gross slip at 1?96 and 4?98 N, mixed stick slip at 9?8 and 14?7 N and near stick at 19?6 N. Samples fretted against alumina counterbody exhibited higher tangential force coefficient values compared to those fretted with other counterbodies. The 304 stainless steel samples fretted with alumina counterbody exhibited higher wear volume due to higher contact stress and tribochemical reaction between the tribopair. The samples fretted against both 304 stainless steel and SAE 52100 steel counterbodies exhibited almost similar wear volume due to similar levels of adhesion between the contacting materials. However, the wear volume of 304 stainless steel samples fretted against Ti-6Al-4V counterbody was the least among all. It is attributed to the fact that dissimilar metals will result in lesser possibility of adhesion leading to better wear resistance. © 2013 W. S. Maney & Son Ltd.