1. Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/1/6
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Item Optimum shape design of rotating disks(1980) Bhavikatti, S.S.; Ramakrishnan, C.V.This paper deals with optimum shape design of the rotating disks by nonlinear programming method. The shape of the cross section is defined by 5th degree polynomial which is completely determined by the boundary conditions and four design variables. The stress analysis of the disk is carried out by finite element method using isoparametric elements. The optimization technique used is with improved movelimit method of sequential linear programming. Progress of optimization is investigated with three different objective functions. After preliminary studies a weighted objective function is selected for detailed investigation. Optimum shapes are obtained for different speeds and for different fit pressures from hub. The results are presented in non-dimensionalised form. 1980.Item Optimum design of multiple barrel shells(1995) Lakshmy, T.K.; Bhavikatti, S.S.This paper is concerned with the optimization of multiple barrel shell roofs. Since the analysis of a multiple barrel shell structure is generally simplified as the analysis of an outer shell and the analysis of an inner shell, optimization of inner and outer shell are studied separately and illustrated. The analysis is based on the well known D.K.J. theory and the design is done in accordance with Indian standard specifications. The capability of two optimization techniques viz; i) improved move limit method of sequential linear programming and ii) sequential unconstrained minimization technique for the optimum design of multiple barrel shells is discussed. The progress of optimization and convergence to global optimum have been studied by both techniques and compared. The effect of cost ratio on the optimum design variables is investigated. Though tables have been prepared which gives the optimum dimensions and area of reinforcements for various design forces in the shell and edge beam for a given span and chordwidth, only a single table has been given here for illustration.Item Optimum design of trough type folded plate roofs(1995) Lakshmy, T.K.; Bhavikatti, S.S.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.Item Minimization of maximum moment in offshore pipeline during installation(1986) Bhavikatti, S.S.; Akram, P.; Ravichandran, T.V.During the laying of an offshore pipeline from a lay barge, the suspended length between the stinger end of the lay barge and sea bed is subjected to significant bending moments. The maximum moment in the pipeline depends on horizontal tension and the lift off angle at the stinger end. The problem of minimization of maximum moment in offshore pipeline is formulated by finding suitable values of horizontal tension and suspended length (and hence lift off angle) such that the maximum bending moment in the pipeline is as low as possible, without violating constraints on the lift off angle and geometric constraints. This is a nonlinear analysis and nonlinear optimization problem. For analysis Datta and Basu's formulation is used and the resulting nonlinear equations are solved by finite difference technique iteratively. The improved move limit method of sequential linear programming is used for optimization. In the present study only static loads are considered and optimum moments are found for one of the pipelines to be used in Bombay High. Progress of optimization, convergence to global optimum and suitability of the optimization technique used are discussed for a particular depth. Then optimum designs are obtained for various depths. It is found that by suitably adjusting the lift off angle the maximum moments can be considerably reduced. The optimum lift-off angle reduces with the depth. 1986 Computational Mechanics Publications.Item Influence lines for bending moments in beams on elastic foundations(1996) Hosur, V.; Bhavikatti, S.S.A finite difference method assuming parabolic variation of contact pressure distribution is presented to obtain the influence lines for bending moments in beams on an elastic foundation. These influence lines can conveniently be used to find moments in beams on elastic foundations due to any type of loads. The computational procedure presented is simple. Accurate results are obtained with only 10 elements.