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