SUPPRESSION OF STRUCTURAL VIBRATIONS OF AN AIR-INFLATED MEMBRANE DAM BY ITS INTERNAL-PRESSURE

The suppression of vibrations in air-inflated membrane dams is conside red. The vibrations are assumed to result from disturbances that inclu de unsteady water flow and wind pressure. A mathematical model describ ing the vibratory motion in the air-inflated membrane and developed in J. C. Hsieh, Free Vibrations of Inflatable Dams, Ph.D. Dissertation, Virginia Polytechnic and State University (1988), is employed for devi sing a strategy for vibration suppression. The governing equations of motion are discretized to include a finite number of vibrational modes . The proposed suppression strategy is developed with the aid of Lyapu nov functions. It has been shown that the suppression of vibrations ca n be accomplished by properly varying the internal pressure. In other words, the pressure by itself is capable of suppressing the vibrations in the membrane. Possible generalization of the proposed suppression scheme to other systems of relevance is discussed. (C) 1997 Elsevier S cience Ltd.