Optimum design of multiple barrel shells

Abstract

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.