Faculty Publications
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Item Optimization of simply-supported symmetrical trough type folded plate roofs using improved move-limit method of sequential linear programming and sequential unconstrained minimization technique is discussed. Improved move-limit method of sequential linear programming has been found to be suitable for optimization of trough type folded plate roofs and using the same, the effect of cost ratio on optimum design variables and the effect of the number of trough units for a given span on optimum design have been studied and discussed. Optimum dimensions have been prepared for various spans normally encountered. © 1995.(Optimum design of trough type folded plate roofs) Lakshmy, T.K.; Bhavikatti, S.S.1995Item Wind tunnel experiments were conducted on a series of two-dimensional perforated plates normal to an air stream to study the characteristics of unsteady wake pressures and to ascertain the parameters amongst which a certain level of correlation can be established. The velocity ranged from 5 m/s to 15 m/s in the present study. The pressure field gets significantly modified as the perforation level increases. The present study is concerned with three plates with perforation level of 0%, 25% and 35%. There appears to be a correlation between the maximum normalized value of the RMS pressure fluctuation levels, base pressure and the perforation level of the normal plate.(Experimental investigation of the 2-D flow field associated with bleed flows) Yaragal, S.C.; Govinda Ram, H.S.; Tamura, Y.2005Item Bending of sandwich plates with anti-symmetric angle-ply face sheets - Analytical evaluation of higher order refined computational models(2006) Swaminathan, K.; Patil, S.S.; Nataraja, M.S.; Mahabaleswara, K.S.The aim of the present study is to assess the accuracy of the few computational models based on various shear deformation theories in predicting the bending behaviour of sandwich plates with anti-symmetric angle-ply face sheets under static loading. Five two-dimensional models available in the literature are used for the present evaluation. The performance of the various models is evaluated on a simply supported laminated plate under sinusoidal loading. The equations of equilibrium are derived using the principle of minimum potential energy (PMPE). Analytical solution method using double Fourier series approach is used in conjunction with the admissible boundary conditions. The accuracy of each model is established by comparing the results of composite plates with the exact solutions already available in the literature. After establishing the correctness of the theoretical formulations and the solution method, benchmark results for transverse displacement, in-plane stresses, moment and shear stress resultants are presented for the multilayer sandwich plates. © 2006 Elsevier Ltd. All rights reserved.Item Analytical solutions using a higher order refined computational model with 12 degrees of freedom for the free vibration analysis of antisymmetric angle-ply plates(2008) Swaminathan, K.; Patil, S.S.Analytical formulations and solutions to the natural frequency analysis of simply supported antisymmetric angle-ply composite and sandwich plates hitherto not reported in the literature based on a higher order refined computational model with 12 degrees of freedom already reported in the literature are presented. The theoretical model presented herein incorporates laminate deformations which account for the effects of transverse shear deformation, transverse normal strain/stress and a nonlinear variation of in-plane displacements with respect to the thickness coordinate thus modelling the warping of transverse cross sections more accurately and eliminating the need for shear correction coefficients. In addition, another higher order computational model with five degrees of freedom already available in the literature is also considered for comparison. The equations of motion are obtained using Hamilton's principle. Solutions are obtained in closed-form using Navier's technique by solving the eigenvalue equation. Plates with varying slenderness ratios, number of layers, degrees of anisotropy, edge ratios and thickness of core to thickness of face sheet ratios are considered for analysis. Numerical results with real properties using above two computational models are presented and compared for the free vibration analysis of multilayer antisymmetric angle-ply composite and sandwich plates, which will serve as a benchmark for future investigations. © 2007 Elsevier Ltd. All rights reserved.Item Comprehensive physical model study on wave transmission at plate structure(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Shirlal, K.G.; Rao, S.; Varghese, R.V.Investigators are increasingly concentrating their focus of research on coastal protection which is shifting from the hard measures to eco-friendly solutions with optimal usage of construction materials. A structure located near the water surface is known to be effective in bringing down the wave activity behind it, since; the energy of the waves is concentrated in the region close to the surface. This paper explains the comprehensive experimental study to evaluate the transmission coefficients (Kt) of various configurations of submerged plate structures. Kt for various plate configurations such as single plate, twin plate and combined plate are obtained. It is found that a single plate inclined at 60° to the horizontal is generally effective i. e. Kt ? 0.6 to a large extent. However, the twin and combined plate structures improved the performance. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Influence of Ti, B and Sr on the microstructure and mechanical properties of A356 alloy(2011) Mallapur, D.G.; Kori, S.A.; Udupa, K.R.In the present investigation, the microstructural and mechanical properties study of A356 alloy have been discussed. The microstructural aspect of cast A356 alloy employed in the present study is strongly dependent on the grain refinement (Ti and B) and modification (Sr). The mechanical properties such as PS, UTS, %E, %R, YM and VHN have been investigated. This paper deals with the combined effect of grain refinement and modification, which improves the overall mechanical properties of the alloy. It is also a well-known fact that the mechanical properties of cast A356 alloy were improved by subjecting suitable melt treatment such as grain refinement, modification and mould vibration, etc. The quality of castings and their properties can be achieved by refining of ?-Al dendrites in A356 alloy by means of the addition of elements such as Ti and B which reduces the size of a-Al dendrites, which otherwise solidifies with coarse columnar a-Al dendritic structure. In addition, modification is normally adopted to achieve improved mechanical properties. Metallographic studies reveal that the structure changes from coarse columnar dendrites to fine equiaxed ones on the addition of grain refiner and further, plate like eutectic silicon to fine particles on addition of 0.20% of Al-10Sr modifier. The present result shows that a reduction in the size of a-Al dendrites, modification of eutectic Si and improvement in the mechanical properties were observed with the addition of grain refiner Al-3Ti, Al-3B and modifier Al-10Sr either individual addition or in combination. The change in the microstructure from coarse columnar ?-Al dendrites to fine equiaxed dendrites and plate like eutectic silicon to rounded particles leads to improved mechanical properties. © Springer Science+Business Media, LLC 2010.Item Computational model for the transverse stress analysis of FGM plates - An assessment(2013) Swaminathan, K.; Naveenkumar, D.T.This paper presents the complete theoretical formulation and the analytical solutions for stress analysis of functionally graded material (FGM) plates using First-order Shear Deformation Theory (FSDT). The material properties are assumed to be isotropic along the plane of the plate and vary through the thickness according to the power law function. The governing equations of equilibrium are derived using Principle of Minimum Potential Energy (PMPE) and the analytical solutions are obtained in closed-form using Navier's solution technique. The effect of variation of side-to-thickness ratio, modulus of elasticity ratio, edge ratio and the power law function on the behaviour of the plate is studied. Numerical results are presented for the transverse displacement, the in-plane and the transverse stresses. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.Item Vibration analysis of a tapered laminated thick composite plate with ply drop-offs(Springer Verlag service@springer.de, 2015) Edwin Sudhagar, P.; Arumugam, A.; Vasudevan, R.; Jeyaraj, J.In this study, vibration characteristics of a tapered laminated thick composite plate have been investigated using finite element method by including the shear deformation and rotary inertia effects. The governing differential equations of motion of a tapered laminated thick composite plate are presented in the finite element formulation based on first-order shear deformation theory for three types of taper configurations. The effectiveness of the developed finite element formulation in identifying the various dynamic properties of a tapered laminated thick composite plate is demonstrated by comparing natural frequencies evaluated using the present FEM with those obtained from the experimental measurements and presented in the available literature. Various parametric studies are also performed to investigate the effect of taper configurations, aspect ratio, taper angle, angle ply orientation and boundary conditions on free and forced vibration responses of the structures. The comparison of the transverse free vibration mode shapes of the uniform and tapered composite plates under various boundary conditions is also presented. The forced vibration response of a composite plate is investigated to study the dynamic response of tapered composite plate under the harmonic force excitation in various tapered configurations. It is concluded that the dynamic properties of laminated thick composite plates could be tailored by dropping off the plies to yield various tapered composite plate. © 2015, Springer-Verlag Berlin Heidelberg.Item Effect of dilution rate on dynamic and steady-state biofilm characteristics during phenol biodegradation by immobilized Pseudomonas desmolyticum cells in a pulsed plate bioreactor(Higher Education Press, 2016) Rangappa, V.B.; Shetty K, K.V.; Bharthaiyengar, S.M.Pulsed plate bioreactor (PPBR) is a biofilm reactor which has been proven to be very efficient in phenol biodegradation. The present paper reports the studies on the effect of dilution rate on the physical, chemical and morphological characteristics of biofilms formed by the cells of Pseudomonas desmolyticum on granular activated carbon (GAC) in PPBR during biodegradation of phenol. The percentage degradation of phenol decreased from 99% to 73% with an increase in dilution rate from 0.33 h–1 to 0.99 h–1 showing that residence time in the reactor governs the phenol removal efficiency rather than the external mass transfer limitations. Lower dilution rates favor higher production of biomass, extracellular polymeric substances (EPS) as well as the protein, carbohydrate and humic substances content of EPS. Increase in dilution rate leads to decrease in biofilm thickness, biofilm dry density, and attached dry biomass, transforming the biofilm from dense, smooth compact structure to a rough and patchy structure. Thus, the performance of PPBR in terms of dynamic and steady-state biofilm characteristics associated with phenol biodegradation is a strong function of dilution rate. Operation of PPBR at lower dilution rates is recommended for continuous biological treatment of wastewaters for phenol removal. [Figure not available: see fulltext.] © 2016, Higher Education Press and Springer-Verlag Berlin Heidelberg.