Shakedown boundary determination of a 90° back-to-back pipe bend subjected to steady internal pressures and cyclic in-plane bending moments

• No shakedown experimental data exist for 90° back-to-back pipe bends.
• A non-cyclic technique is utilized to generate the elastic shakedown boundary.
• The non-cyclic technique succeeded in generating the structure's Bree diagram.
• The non-cyclic technique correlated well with full cyclic loading FE simulations.

No experimental data exist within open literature, to the best knowledge of the author, for determining shakedown boundaries of 90° back-to-back pipe bends. Ninety degree back-to-back pipe bends are extensively utilized within piping networks of nuclear submarines and modern turbofan aero-engines where space limitation is considered a paramount concern. In the current research, the 90° back-to-back pipe bend setup analyzed is subjected to a spectrum of steady internal pressures and cyclic in-plane bending moments. A previously developed direct non-cyclic simplified technique for determining elastic shakedown limit loads is utilized to generate the elastic shakedown boundary of the analyzed structure. The simplified technique outcomes showed excellent correlation with the results of full elastic–plastic cyclic loading finite element simulations.