Designing bended pipes under internal pressure

Abstract

There are major benefits, e.g. in the aerospace sector, for lightweight mobile applications, because of integral lightweight design and construction. Integral lightweight design avoids parting points, as they increase the weight and at the same time could cause defects. Pipe technology is a potential application for this issue. For the design of bended pipes, there are various conventional but only few FEM-based approximation methods that consider fiber plastic composites. This optimization was carried out, especially for high-pressure components with an expected burst pressure of approx. 1,050 bar (approx. 15,200 psi), consisting of liner and multi-layer laminate. Three different optimization methods with adapted material parameters were compared. The net theory was used first. Furthermore, the Tsai–Wu failure criterion was considered. The inter-fiber-failure-criterion of Cuntze has been used for straight pipes. Subsequently, variations in terms of curvature angles, curvature radii, and pipe size for various laminates has been shown in theoretical investigations. The result section provides the inverse reserve factor and an outlook on the expected weight for various fiber combinations.