Codice QDD 146 Titolo Free vibrations in space of the single mode for the Kirchhoff string Data 2013-02-01 Autore/i Marchionna, C. Link Download full text Pubblicato Communications on Pure and Applied Analysis Abstract We study a single mode for the Kirchhoff string vibrating in space. In 3D a single mode is generally almost periodic in contrast to the 2D periodic case. In order to show a complete geometrical description of a single mode we prove some monotonicity properties of the almost periods of the solution, with respect to the mechanical energy and the momentum. As a consequence of these properties, we observe that a planar single mode in 3D is always unstable, while it is known that a single mode in 2D is stable (under a suitable definition of stability), if the energy is small.