Faculty Publications
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Item Finite Element Modelling and Experimental Validation of Strain Gauge Pasted Over the Surface of a Substrate Subjected to a Transverse Load(Springer, 2024) Raveesh, R.M.; Kaliveeran, V.; Kundapura, S.The strain measurement is important as it directly involves with the deformation of a structure in the field of engineering. Strain is a measure of change in shape that occurs when an external load is applied to an engineering assembly. The evaluation of the strain is used to determine the amount of extension or deformation a structure experiences under different loading conditions. Strain gauges are electrical resistance sensors bonded at critical locations on the surface of structural components to detect surface deformation. Strain gauges are frequently used to continuously check for deformations to avoid accidents that can occur in nuclear power plants, aerospace vehicles, mechanical components, and structures. Strain gauges applied directly to the specimen are partially affected by the bonding material and thickness when tested. Present work intends to study the effect of adhesive thickness on strain values. Adhesives are used to paste strain gauges over the surface of the specimen. Three-Dimensional analysis of the strain gauge model has been carried out with the aid of the Finite element software. Experiments were conducted to study the effect of adhesive thickness by varying the thickness of the adhesive from 0.1 to 1 mm by pasting strain gauge over the surface of the Aluminium specimen of length 230 mm, width of 30 mm, and thickness of 6 mm. The strain values obtained from the finite element analysis were compared with the strain values obtained from the experiments. Finite element analysis results were found to be in good correlation with the experimental results. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Electrical and magneto-resistance of Co/CNT/Epoxy thin film for strain and magnetic field sensing(2009) Anand, S.V.; Isaac, R.; Roy Mahapatra, D.R.Cobalt and iron nanoparticles are doped in carbon nanotube (CNT)/polymer matrix composites and studied for strain and magnetic field sensing properties. Characterization of these samples is done for various volume fractions of each constituent (Co and Fe nanoparticles and CNTs) and also for cases when only either of the metallic components is present. The relation between the magnetic field and polarization-induced strain are exploited. The electronic bandgap change in the CNTs is obtained by a simplified tight-binding formulation in terms of strain and magnetic field. A nonlinear constitutive model of glassy polymer is employed to account for (1) electric bias field dependent softening/hardening (2) CNT orientations as a statistical ensemble and (3) CNT volume fraction. An effective medium theory is then employed where the CNTs and nanoparticles are treated as inclusions. The intensity of the applied magnetic field is read indirectly as the change in resistance of the sample. Very small magnetic fields can be detected using this technique since the resistance is highly sensitive to strain. Its sensitivity due to the CNT volume fraction is also discussed. The advantage of this sensor lies in the fact that it can be molded into desirable shape and can be used in fabrication of embedded sensors where the material can detect external magnetic fields on its own. Besides, the stress-controlled hysteresis of the sample can be used in designing memory devices. These composites have potential for use in magnetic encoders, which are made of a magnetic field sensor and a barcode. © 2009 SPIE.Item Design and Development of Efficient Under-Drainage System for Lined Canals(Springer Science and Business Media Deutschland GmbH, 2021) Sharma, A.; Das, B.B.Under-drainage system for lined canal is present beneath the canal bed to drain off the water present over there. It consists of longitudinal and transverse perforated drain pipes along with the arrangement of pressure relief valves. Cases of failure of lining of canal are there due to inconsistency in under-drainage system. Performance of geocell is exceptionally well in soil compaction, slope stabilization, earth retention and as reinforcement in case of retaining structure, road construction and railway embankments. Contrary to other researches, here performance of geocell as reinforcement of buried pipe under canal bed is investigated. Experimental study is carried out on canal model and on an under-drainage system. Strain in the buried pipe is observed due to application of various loading patterns on canal model. For sustained loading, 29% increase in strain is observed in pipe buried in unreinforced soil as compared to 18% in pipe buried in reinforced soil. For maximum loading almost three times more strain is stored in pipe in unreinforced soil. Yield is also observed in pipe without geocell, whereas at same loading no such behaviour is observed in pipe with geocell. It is reported that geocell can act as reinforcement for buried drain pipes under canal bed, and this helps in making under-drainage system efficient. © 2021, Springer Nature Singapore Pte Ltd.Item Numerical investigations on the strength of L-shaped short reinforced concrete columns subjected to combined axial load and bending were undertaken for the purpose of providing design aids for structural engineers. The use of a computer lends itself naturally to the solution of the problem which generally requires an iterative process. Therefore, an attempt has been made in this paper to computerize the analysis procedure for L-shaped sections and in the accompanying paper (part II)‡ for T-shaped column sections. The ACI-318, CP-110 and IS-456 codes presented design aids only for square/rectangular and circular columns. Apparently this study constitutes the first to present the interaction curves for L-shaped and T-shaped column sections with the limit state analysis. © 1992.(Computer aided analysis of reinforced concrete columns subjected to axial compression and bending-I L-shaped sections) Mallikarjuna; Mahadevappa, P.1992Item 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 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 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.(Hardness-stress-strain correlation in copper and brass through compression testing) Dharmaveera, N.; Srinivasan, K.1996Item This paper deals with an experimental investigation concerning the open die extrusion (ODE) of three materials of varying physical properties and mechanical properties. Two geometrical configurations (solid and tube) and two methods (by direct and indirect techniques) were considered to examine the influence of these variables in the generation and retention of heat in the deformation zone with the objective of ensuring a greater achievable strain. Studies reveal that solid configuration supports the retention of heat as against tubular configuration. Low thermal conductivity, density, specific heat and high flow stress which characterise 99Ti make this material an excellent candidate for ODE as opposed to AISI 1020 steel and aluminium, which fail to meet all the above physical and mechanical properties. The indirect technique reduces the friction factor and thus enables greater strains to be achieved. © 1997 Elsevier Science S.A.(Elsevier BV, Adiabatic and friction heating on the open die extrusion of solid and hollow bodies) Srinivasan, K.; Venugopal, P.1997Item CP aluminium was subjected to axysymmetric compression testing at 303, 373, 473, 573 and 673 K. Strength coefficient and strain hardening exponent were determined from log-log plot of true stress and true strain at different temperatures. True stress vs temperature at different strains indicated that dynamic strain ageing (DSA) occurred between 473 and 673 K. Warm working is to be done between 423 K and 473 K, so that optimum substructure hardening and strain hardening can be achieved during mechanical processing. © Indian Academy of Sciences.(Indian Academy of Sciences, High temperature compression testing and determination of warm working temperature for commercial purity aluminium) Rao, B.K.; Khadar, M.S.A.; Srinivasan, K.1999Item An investigation was carried out to examine the influence of chromium content on the plane strain fracture toughness of austempered ductile iron (ADI). ADIs containing 0, 0.3 and 0.5 wt.% chromium were austempered over a range of temperatures to produce different microstructures. The microstructures were characterized by optical microscopy and X-ray diffraction. Plane strain fracture toughness of all these materials was determined and correlated with microstructure and chromium content. The chromium content was found to influence the fracture toughness through its influence on the processing window. Since the chromium addition shifts the processing window to shorter durations, the higher chromium alloys at higher austempering temperatures tend to fall outside of the processing window, resulting in less than optimum microstructure and inferior fracture toughness. A small chromium addition of 0.3 wt.% was found to be beneficial for the fracture toughness of ADI. © 2002 Elsevier Science B.V. All rights reserved.(Elsevier BV, Investigations on the fracture toughness of austempered ductile iron alloyed with chromium) Prasad Rao, P.; Putatunda, S.K.2003
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