Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
26 results
Search Results
Item Equal channel angular processing-a modern deforming technique for quality products(Elsevier, 2021) Bhat K, U.K.; Bhat Panemangalore, D.B.; Bhat, S.The grain size plays a significant role in determining the mechanical properties of the materials. Decreasing grain size increases strength, toughness, and ductility. Due to these, a lot of research has been executed to develop deforming techniques to produce ultrafine-grained materials. Among several plastic deformation techniques available, equal channel angular pressing or processing (ECAP) produces ultra-fine grained materials with substantial amount of high angle grain boundaries. ECAP produces ultra-fine grained material with typical substructural features, which are difficult to achieve using other severe deformation techniques. This chapter presents characteristics, variables, die design, and die materials employed in the process. The chapter also presents recent developments in the domain, such as, use of finite element techniques, etc. © 2021 Elsevier Inc. All rights reserved.Item Effect of Load Inclination on the Lateral Resistance of Belled Piles: A Numerical Approach(Springer Science and Business Media Deutschland GmbH, 2025) Bariker, P.; Kolathayar, S.Belled piles are commonly used in geotechnical engineering to provide foundation support in unstable soils. These piles are characterized by an enlarged base, increasing the pile’s load-bearing capacity. Inclined loads are experienced in various engineering applications, such as retaining walls, bridge abutments, and slope stabilization. This study conducts a numerical analysis of belled piles subjected to inclined loads using a finite element approach. The present study investigates the behaviour of belled piles under inclined loads and evaluates their performance in terms of deformation, stress distribution, and load-carrying capacity. The model considers the interaction between the pile and the surrounding soil. The inclined load is applied at various angles to investigate its effect on the pile response. The numerical analysis reveals that several factors, including the angle and magnitude of the applied load, the L/D ratio and the geometry of the belled pile, influence the behaviour of the belled pile under an inclined load. The results show that the deformation and stress distribution in a pile is influenced by the inclination angle of the applied load, with higher inclination angles resulting in larger pile deformations and stress concentrations at the base of the pile. The lateral resistance of the belled pile with a bell angle of 3° significantly carries 21% more load than that of 7°. The findings of this study provide insights into the behaviour of belled piles subjected to inclined loads. They can be used to guide the design and analysis of belled pile foundations in geotechnical engineering projects. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Cu-44Ni-5Cr alloy has been subjected to thermomechanical treatment which consisted of plastic deformation of as-quenched material by 50, 65 and 80% reduction in thickness followed by ageing in the interval of 500 to 650 °C for various durations of time. Progress in age-hardening was studied by means of hardness measurement and X-ray diffraction studies. The wavelength of composition modulation and strain amplitude were measured. It was found that age-hardening was a result of interaction between spinodal decomposition and recovery processes. Prior deformation was found to enhance the kinetics of both spinodal decomposition and coarsening. It was concluded that this resulted from increased vacancy concentration and increased coherency strain in the cold-worked material. © 1994 Chapman & Hall.(Kluwer Academic Publishers, Effect of thermomechanical treatment on the phase transformation in Cu-44Ni-5Cr alloy) Raghavendra Bhat, R.; Prasad Rao, P.1994Item Progress in spinodal decomposition of a Cu-32Ni-2Cr alloy subjected to quench?age and quench?work?age treatments have been studied through hardness measurements as well as by X-ray diffraction techniques. It is found that recovery processes occur during early stages of aging which are interpreted in terms of the migration of matrix dislocations to interfaces. The kinetics of spinodal decomposition is found to be enhanced by prior deformation. Thermomechanical treatment results in a substantial increase in strength.(Publ by Carl Hanser Verlag GmbH & Co, Thermomechanical treatment of spinodal Cu-32Ni-2Cr alloy) Bhat, R.Raghavendra; Prasad Rao, P.1994Item 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.(Indian Academy of Sciences, Hardness-stress-strain correlation in aluminium - A simpler alternative to visioplasticity in metal forming) Dharmaveera, N.; Srinivasan, K.1996Item A heterogeneous process such as open die extrusion has been done on CP titanium and the extent of heterogeneity has been determined. The pressure for carrying out the process has been calculated theoretically, measured experimentally and calculated indirectly from hardness measurement in the deformation zone. Hardness-stress-train correlation is very useful here. A nomogram has been given so that knowing, ?, ?, ? and hardness, the punch pressure can be read off. It is a steady-reckoner that is very relevant for the shop floor in industry or the laboratory.(Elsevier Science S.A., Hardness-stress-strain correlation in titanium open die extrusion: an alternative to visioplasticity) Srinivasan, K.; Venugopal, P.1999Item Open die extrusion (ODE) has been done on AISI 1020 steel, commercial purity aluminium and commercial purity titanium, in both direct and inverted modes. It was found that inverted extrusion requires lesser forces than direct extrusion. Limit strains are more for the former than for the later as measured experimentally and as calculated theoretically. Theoretical limit strains are lesser than experimental ones in both the case of rods and tubes. ODE is only for shorter components due to unsupported billet and interference from buckling. It is also only for smaller strains due to interference from upsetting of unsupported billet above the die rather than extrusion through the die. © 2004 Elsevier B.V. All rights reserved.(Direct and inverted open die extrusion (ODE) of rods and tubes) Srinivasan, K.; Venugopal, P.2004Item Static analysis of functionally graded beams using higher order shear deformation theory(2008) Kadoli, R.; Akhtar, K.; Ganesan, N.Displacement field based on higher order shear deformation theory is implemented to study the static behavior of functionally graded metal-ceramic (FGM) beams under ambient temperature. FGM beams with variation of volume fraction of metal or ceramic based on power law exponent are considered. Using the principle of stationary potential energy, the finite element form of static equilibrium equation for FGM beam is presented. Two stiffness matrices are thus derived so that one among them will reflect the influence of rotation of the normal and the other shear rotation. Numerical results on the transverse deflection, axial and shear stresses in a moderately thick FGM beam under uniform distributed load for clamped-clamped and simply supported boundary conditions are discussed in depth. The effect of power law exponent for various combination of metal-ceramic FGM beam on the deflection and stresses are also commented. The studies reveal that, depending on whether the loading is on the ceramic rich face or metal rich face of the beam, the static deflection and the static stresses in the beam do not remain the same. © 2007 Elsevier Inc. All rights reserved.Item Study of the properties of SCC with quarry dust(2009) Gowda, M.R.; Narasimhan, M.C.; Karisddappa; Rajeeva, S.V.Granite fines or rock dust is a by-product obtained during crushing of granite rocks and is also called quarry dust (QD). This paper deals with using quarry dust as an alternative to fine aggregate (FA) in SCC and reports the strength behaviour and hardened properties of such SCCs. Although in normal concretes, introducing QD increases the water demand, in SCC, it has been successfully used for increasing the deformability and passing ability of fresh concrete. Also, it was noted that by increasing the pouring heights of an SCC, the compressive strength and splitting tensile strength of concrete were unaffected.Item 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.
- «
- 1 (current)
- 2
- 3
- »