Stability enhancement of beam-type structures by piezoelectric transducers: theoretical, numerical and experimental investigations.

Subject of the present work is the enhancement of the buckling load of beam-type structures under a compressive force by means of active feedback control. The focus of this paper lies on experimental aspects that show the feasibility of the proposed approach. For this purpose, a cantilever beam loaded by a compressive force is considered. The compressive force is applied with the help of a cable which is fixed at the tip of the free end and passes through the foundation of the cantilever. A laser displacement sensor is used to measure the structural displacements at the beam's tip. For actuation, piezoelectric transducers are attached on each side of the cantilever beam. Two kinds of constant gain feedback control approaches are investigated on the experimental setup. The buckling load could be increased by a factor of 2.05. The experimental results agree very well with the performed numerical simulations. As a theoretical basis, a consistent theoretical formulation is presented using the Bernoulli-Euler beam theory. The formulation of the system includes also a general feedback controller with discrete displacement measurements and distributed piezoelectric patches. The influence of the controller on the buckling load, control amount by means of applied voltage and limits of the investigated active buckling control approaches are emphasized. [ABSTRACT FROM AUTHOR]