VIBRATION CONFINEMENT IN FLEXIBLE STRUCTURES VIA ALTERATION OF MODE SHAPES BY USING FEEDBACK

A novel strategy for confining the vibrations to parts of a flexible s tructure is proposed. The method of vibration confinement consists of converting the original mode shapes of continuous systems to exponenti ally decaying functions. The confinement is first achieved by applying appropriate distributed feedback forces. The implementation by a fini te number of discrete feedback forces is also investigated. The error introduced by replacing the distributed actuator by discrete ones is q uantified by means of partitioned matrices. It is shown that this erro r can be controlled and if certain orthogonality conditions are satisf ied it can be made zero for the controlled modes. Simulations for a vi brating string are presented to show the effectiveness of the method. The proposed strategy may be of particular use if there is interest in eliminating unwanted vibrations from certain parts of a flexible stru cture more than from others, or in preventing a localized excitation f rom propagating into certain parts.