Electrostatically tunable bending stiffness in a GFRP–CFRP composite beam

Abstract

The suppression of vibrations in structures is commonly considered a useful measure for theextension of their lifetime, when high amplitude vibrations are observed. In theexperiments presented in this work, the modification of the stiffness of a beam as ameans to suppress vibrations due to resonance is proposed as an alternative to theintroduction of discrete damping devices. The stiffness of a beam is modified byapplying an electric field between the main element of the structure and additionalstiffening elements applied to its surface, thus coupling the latter to the former bytransfer of shear stresses. The effect of electrostatic tuning of the bending stiffness(and consequently of its eigenfrequencies) of a large size GFRP–CFRP beam isshown by the shift of the resonance peak for the first bending mode to higherfrequencies. The discrete character of the stiffness increase in multi-layer beams(n≥3) is postulated.