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Item Hardness-stress-strain correlation in copper and brass through compression testing(1996) Dharmaveera, N.; Srinivasan, K.A simple method of characterizing local stress and local strain variation in metal working is suggested. It is an alternative to complex and time consuming visioplastic technique. A power law expression exists for hardness and strain similar to that of stress and strain. A linear expression relating hardness and stress has been estahlished. These are valid not only for pure metals but also for their alloys. Meshap Science Publishers.Item Hardness-stress-strain correlation in aluminium - A simpler alternative to visioplasticity in metal forming(1996) Dharmaveera, N.; Srinivasan, K.Local stress and strain variations in the deformation zone can be ascertained by measuring hardness. Hardness is correlated with strain and stress. The expressions discussed later are useful in determining the local variations in stress and strain from hardness measurement. It is a simple method compared to visioplasticity. One can estimate the forces required for a forming process. It helps in the choice of equipment, design of tooling and selection of lubricant for the particular process.Item Finite element analysis of open die extrusion of al-5zn-1mg alloy [Analiza izguravanja legure al-5zn-1mg kroz otvoreni kalup pomo]u kon?nih elemenata](2009) Geethalakshmi, K.; Srinivasan, K.In this work, an effort has been made to study the open die extrusion of Al-5Zn-1Mg alloy using finite element analysis. The two basic parameters of open die extrusion, i.e., die included angle and the extrusion strain are varied to find the corresponding limiting strain values. Effect of main parameters on the open die extrusion is analyzed, and the limiting range of deformation is obtained. The results obtained are verified by means of contrasting with the experimental data. Pure open die extrusion is found to be possible for extrusion strain (relative strain during extrusion) up to 0.28. However, as the extrusion strain increases from 0.09 to 0.28, upsetting dominates over pure extrusion on varying the die angle from 12 to 40 .Item Influence of die angle on containerless extrusion of CP titanium rods(2005) Srinivasan, K.; Venugopal, P.As the name implies containerless extrusion is done without container and the total force consists of three individual terms namely ideal force, shear force and die friction force. Container wall billet friction is absent. The shear force varies directly with die angle, die friction force varies inversely with Sine of twice the die angle and ideal force is independent of angle. At a particular angle the total force is minimum. This is termed as optimum die angle. This can be understood from slab analysis of the process. Theoretically the optimum die angle varies only with extrusion strain and friction factor. It is found to change from 25� at a strain of 0.15 to 30� at a strain of 0.42. Experimentally the optimum angle is found to be independent of strain and at all strains it is found to be 25� at a constant friction factor of 0.14. More over the experimental pressure is less than that-predicted by theory. This is attributed to the temperature rise in the deformation zone and a consequent decrease in flow stresses of titanium.