2026-05-07T09:28:48Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/83002024-05-14T09:50:34Zcom_10259_7509com_10259_4266com_10259.4_106com_10259_2604com_10259_6214com_10259_5086col_10259_7510col_10259_6215

Cold Expansion Process with Multiple Balls—Numerical Simulation and Comparison with Single Ball and Tapered Mandrels Curto Cárdenas, David Calaf Chica, José Bravo Díez, Pedro Miguel Preciado Calzada, Mónica García Tárrago, María José Cold expansion Swaging Ball Aeronautical Simulation Experimental Cold expansion technology is an extended method used in aeronautics to increase fatigue life of holes and hence extending inspection intervals. During the cold expansion process, a mechanical mandrel is forced to pass along the hole generating compressive residual hoop stresses. The most widely accepted geometry for this mandrel is the tapered one and simpler options like balls have generally been rejected based on the non-conforming residual hoop stresses derived from their use. In this investigation a novelty process using multiple balls with incremental interference, instead of a single one, was simulated. Experimental tests were performed to validate the finite element method (FEM) models and residual hoop stresses from multiple balls simulation were compared with one ball and tapered mandrel simulations. Results showed that the use of three incremental balls significantly reduced the magnitude of non-conforming residual hoop stresses and the extension of these detrimental zone. 2024-01-11T11:40:17Z 2024-01-11T11:40:17Z 2024-01-11T11:40:17Z 2020-12 info:eu-repo/semantics/article http://hdl.handle.net/10259/8300 10.3390/ma13235536 1996-1944 eng Materials. 2020, V. 13, n. 23, 5536 https://doi.org/10.3390/ma13235536 http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess Atribución 4.0 Internacional MDPI