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Author: Yeh-Liang Hsu (1994-03-01); recommended: Yeh-Liang Hsu (2010-06-19).
Note: This paper is published in The Chinese Journal Of Mechanics, Vol. 10, No. 1, pp. 11-19, March 1994.

The curvature function method for optimal thickness profile design at discontinuities of axisymmetric shells

Abstract

Discontinuities in a shell structure cause stress concentration. An axisymmetric shell thickness optimization procedure is developed in this study to find the minimum weight thickness profile which reduces the stress concentration to an allowable value. In this procedure, the Curvature Function Method has been coupled with the FAST1 shell analysis program. This method employs curvatures of the thickness profile as design variables. It is a zero order optimization method which requires only stress values along the shell, not gradient of the stresses with respect to the design variables, in addition, the resulting thickness curve has C2 continuity. Though the method is independent of structural analysis program, FAST1 provides a particular advantage since it permits the user to model complex shells with only a few large shell elements and still retain a sufficiently accurate solution. Thus both preparation and computation time are substantially reduced. Various shell models with different types of discontinuities have been optimized by this procedure.

Keywords: shape optimization, the curvature function method, zero order optimization.