Determinantal method for locally modified structures. Application to the vibration damping of a space launcher.

Denis Brizard (1) , Sébastien Besset (1) , Louis Jezequel (1) , Bernard Troclet (1)

1 LTDS - Laboratoire de Tribologie et Dynamique des Systèmes

In order to improve the dynamic behaviour of an existing or already designed structure, local modifications can be performed by taking advantage of the relative displacement between two points of the structure. A stiffner, damper or viscoelastic rod may be added and its effect on the initial structure must be assessed. A new formulation is developed, based on the response of the initial structure at the attachment points of the local modification. A determinantal equation results, whose roots are the eigenvalues of the modified structure. The equation is solved numerically with a dedicated algorithm and it is shown that this is faster than performing an eigenvalue problem reanalysis. The method is able to deal with both undamped and damped systems, and can handle several modifications simultaneously. It is applied on the last stage of a space launcher, along with a double modal synthesis method.

Domaines: Mécanique des structures [physics.class-ph]; Mécanique des structures [physics.class-ph]; Vibrations [physics.class-ph]; Vibrations [physics.class-ph]

Denis Brizard, Sébastien Besset, Louis Jezequel, Bernard Troclet. Determinantal method for locally modified structures. Application to the vibration damping of a space launcher.. Computational Mechanics, 2012, 50 (5), pp 631-644. ⟨hal-00989367⟩