• Aravind Vadiraj

      Articles written in Sadhana

    • Engagement characteristics of a friction pad for commercial vehicle clutch system

      Aravind Vadiraj

      More Details Abstract Fulltext PDF

      A commercially available sintered friction pad is coupled with a standard gray cast iron pressure plate (FG 250 grade) and tested in a clutch dynamometer for understanding the engagement characteristics and thereby predicting the useful life in number of engagements. Results show that sintered friction pad has a very stable range of friction coefficient (0·43–0·61) even after 5000 engagement cycles. The torque transmitted ranges from 350 to 400 N during one engagement cycle. The energy dissipation and mass loss of friction materials linearly increases with increasing sliding distance. A correlation is derived based on energy dissipation and mass loss in terms of total number of useful or available engagements before replacement or repair of friction pad or clutch pressure plate. Both the pressure plate and clutch disc with the sintered friction pad was tested in a 49 tons load capacity vehicle on a test track. Both sintered friction pad and pressure plate showed scoring marks along the sliding direction. Friction pad showed dense cracks along the top edge. Microscopic features of worn sintered friction pads show silica particle providing the required wear resistance for the pads. Pressure plate showed transfer layer of oxides and carbon with less scoring marks due to short duration vehicle level trials.

    • Effect of solid lubricants on friction and wear behaviour of alloyed gray cast iron

      Aravind Vadiraj M Kamaraj V S Sreenivasan

      More Details Abstract Fulltext PDF

      Friction and wear behaviour of MoS2, boric acid, graphite and TiO2 at four different sliding speeds (1.0, 1.5, 2.0, 2.5 m/s) has been compared with dry sliding condition. MoS2 and graphite show 30 to 50% reduction in mass loss compared to other lubricants at all sliding speeds. Friction coefficient reduces with increase in sliding speeds for all the conditions. Friction coefficient of dry as well as lubricant coated samples varies from 0.2 to 0.55 with MoS2 showing the lowest value (0.2). Boric acid and TiO2 coated samples show high friction coefficients at higher sliding speeds due to poor lubricity and adherence. This could also be due to sliding resistance offered by lubricant coated samples with predominant asperities interaction. MoS2 and graphite coated samples also generated lowest frictional temperature compared to other conditions.

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