Shape optimisation of axisymmetric cylindrical nozzles in spherical pressure vessels subject to stress constraints

• Published in: The International journal of pressure vessels and piping Vol. 78; no. 1; pp. 1 - 9
• Main Authors: Liu, J.-S., Parks, G.T., Clarkson, P.J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2001; Elsevier
• Subjects: Axisymmetric structures; benchmarks; Computational techniques; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Finite-element and galerkin methods; High-pressure and shock-wave effects in solids and liquids; Intersection structures; Mathematical methods in physics; Mechanical and acoustical properties of condensed matter; Metamorphic development; Nozzles; Physics; Pressure vessels; Shape optimisation; Stress concentration; Stress concentration; Pressure vessels; Axisymmetric structures; Intersection structures; Nozzles; Shape optimisation; Metamorphic development; Intersection; Variable thickness shell; Prestressed material; Quadrilateral finite element; Theoretical study; Cylindrical shape; Axial symmetry; Optimal design; Spherical shell; Finite element method; Metamorphism
• ISSN: 0308-0161; 1879-3541
• DOI: 10.1016/S0308-0161(00)00065-X

In this study, optimal shapes of intersecting pressure vessels are sought using a novel topology/shape optimisation method, called Metamorphic Development (MD). An industrial benchmark design problem of finding the optimal profile of variable thickness that connects a spherical shell pressure vessel to a cylindrical nozzle is considered. Two types of intersecting structures, distinguished by flush and protruding nozzles, are investigated. The optimum profiles of minimum mass intersecting structures are found by growing and degenerating simple initial structures subject to stress constraints. The optimisation seeks to eliminate the stress peaks caused by the opening. The optimised structures are developed metamorphically in specified infinite design domains using both rectangular and triangular axisymmetric finite elements that are ideally suited for modelling continua with curved boundaries. It is shown that the design with a protruding nozzle would produce a better stress distribution than the design with a flush nozzle. The results demonstrate the success of the method in generating suitable, practical solutions to the design problem.