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    Role of zirconia filler on friction and dry sliding wear behaviour of bismaleimide nanocomposites
    (2011) Kurahatti, R.V.; Surendranathan, A.O.; Srivastava, S.; Singh, N.; Ramesh Kumar, A.V.; Suresha, B.
    This paper discusses the friction and dry sliding wear behaviour of nano-zirconia (nano-ZrO2) filled bismleimide (BMI) composites. Nano-ZrO2 filled BMI composites, containing 0.5, 1, 5 and 10wt.% were prepared using high shear mixer. The influence of these particles on the microhardness, friction and dry sliding wear behaviour were measured with microhardness tester and pin-on-disc wear apparatus. The experimental results indicated that the frictional coefficient and specific wear rate of BMI can be reduced at rather low concentration of nano-ZrO2. The lowest specific wear rate of 4×10-6mm3/Nm was observed for 5wt.% nano-ZrO2 filled composite which is decreased by 78% as compared to the neat BMI. The incorporation of nano-ZrO2 particles leads to an increased hardness of BMI and wear performance of the composites shows good correlation with the hardness up to 5wt.% of filler loading. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © 2011 Elsevier Ltd.
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    Friction and dry sliding wear behaviour of Ni filled epoxy nanocomposite
    (2011) Kurahatti, R.V.; Suredranathan, A.O.; Kori, S.A.; Ramesh Kumar, A.V.; Mordina, B.; Mallapur, D.G.
    Nanosized metal particle filled polymer composites are finding numerous tribological applications in recent years. In the present work, the matrix properties were investigated by introducing nickel nanoparticles (60-100 nm, filler content of 0?5-10 wt-%) into epoxy resin. The influence of these particles on friction and dry sliding wear behaviour was measured using a pin on disc wear set-up. The experimental results indicated that the coefficient of friction and the specific wear rate of epoxy resin can be reduced with a rather low weight fraction of Ni particles. The lowest specific wear rate of 0?6461024 mm3 N21 m21 (compared to neat resin's value of 2?261024 mm3 N21 m21) was observed for composites with the filler content of 0?5 wt-%. The reinforcement of Ni particles leads to improved mechanical properties of the epoxy composites. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © 2011 W. S. Maney & Son Ltd.
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    Role of nickel filler on friction and dry sliding wear behavior of bismaleimide nanocomposite
    (2011) Kurahatti, R.V.; Surendranathan, A.O.; Srivastava, S.; Singh, N.; Ramesh Kumar, A.V.; Kori, S.A.
    Nano-sized metal particles filled polymer composites are finding numerous tribological applications in recent years. In the present work, the matrix properties were investigated by introducing nickel (Ni) nanoparticles (60-100 nm, weight fractions of 0.5-10 %) into a bismaleimide (BMI) resin. The influence of these particles on the microhardness, friction and dry sliding wear behavior were measured using microhardness tester, pin-ondisc wear set up. The experimental results indicated that the coefficient of friction and the specific wear rate (SWR) of BMI resin can be reduced at rather low weight fraction of Ni particles. The lowest SWR of 9 ×10 -6 mm 3/Nm (i.e. 50% lower than the value of neat BMI) was observed for the nanocomposite with Ni weight fraction of 1%. The incorporation of Ni particles leads to an increased hardness of BMI and the wear performance of the composites shows good correlation with the hardness. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © 2011 CAFET-INNOVA TECHNICAL SOCIETY.
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    Experimental determination of spring back and thinning effect of aluminum sheet metal during L-bending operation
    (Elsevier Ltd, 2014) Dilip Kumar, K.; Appukuttan, K.K.; Neelakantha, V.L.; Naik, P.S.
    In automotive industry, significant efforts are being put forth to replace steel sheets with aluminum sheets for various applications. Besides its higher cost, there are several technical hurdles for wide usage of aluminum sheets in forming. Major problems in aluminum sheet metal forming operations are deformation errors and spring back effect. These problems are dependent on the number of parameters such as die and tool geometry, friction condition, loading condition and anisotropic properties of the metal.To predict the exact shape, the geometry based punch contact program must be used. The shape changes once the punch is withdrawn, because of the materials elasticity. Prediction of such a spring back effect is a major challenging problem in industry involving sheet metal forming operations. It also needs applying appropriate back tension during the forming complex shapes. Slight deformation of the metal leads to non-axisymmetric loading. One can predict the residual stress by determining plastic and elastic deformation. Thus appropriate spring back effect can be investigated.The present investigation was carried out to determine the spring back and thinning effect of aluminum sheet metal during L-bending operation. Number of specimens with thickness varying from 0.5. mm to 3.5. mm were prepared. The experiments were conducted for different clearances between punch and die. It is observed that, beyond a particular clearance for each thickness of the sheet metal, the spring back and thinning effects were linearly increasing. However, below the critical clearance, scratches on the surface of the sheet metal were seen due to wear. The scratches were analyzed through Scanning Electron micrographs. As the clearance between punch and die reduces further, more wear on the punching surface was observed. And, as the clearance increases it leads to increase the spring back effect and fracture propagation. © 2013 Elsevier Ltd.