Author(s)

H. Martikka, I. Pöllänen & E. Taitokari

Abstract

In this paper results of studying the task of increasing the reliability of piping branch connections of stainless steel by redesign are discussed. The background is recurrent problems of fracture failures of conventional constructions. Optimum design algorithm and models are applied to a 2D branch section with the fuzzy goal of achieving a small enough toe area and a large enough local strain fatigue life. The design variables are fillet size and form. Stress concentration reduction by local plastic yielding is taken into account using the Ramberg Osgood material model. The conventional 3D piping branch case is optimised using the required method of standards and FEM. An innovative solution is synthesised using fibre based filament strengtheners in thin pipes. It is designed optimally by FEM and the elastic stress concentration at the toe can be reduced from below ten to close to one. This means that considerable increases in mean time to failure can be achieved cost effectively compared to other solutions. Keywords: shape and topology optimisation industrial examples of design optimisation, performance based design. 1 Introduction Background for this study is need of enhancing the reliability of piping branch connections of stainless steel. These are important and widely used in industry.

Keywords

shape and topology optimisation industrial examples of design optimisation, performance based design.