Passive damping of the beam elements of antenna systems

Abstract

Beams are one of the most common elements of antennas - they can be used both as elements for receiving and transmitting radio signals, and as design solutions for various purposes. The paper considers a hinged-supported composite beam consisting of symmetrical layers reinforced with fiber with a viscoelastic coating. The representative element forming the beam layer consists of a fiber, a viscoelastic layer and a matrix. To assess the effect of the volumetric content of reinforcing fiber with a viscoelastic coating on the loss coefficient of a layered composite beam, the viscoelastic analogy method is used, within which the properties of a viscoelastic material are specified by complex quantities. And to evaluate the effect of the volumetric content of reinforcing fiber with a viscoelastic coating on the loss modulus of the composite material, the three-phase method extended to a multiphase medium and the viscoelastic analogy method are used. A study is also carried out to study the influence of the ratio of the real parameter of the loss modulus of the viscoelastic layer to the shear modulus of the reinforcing fiber on the effective transverse loss modulus of the composite material and on the loss coefficient of the laminated composite beam. Numerical values of the effective transverse loss moduli for the composite material under study and the loss coefficients of a simply supported beam are given depending on the thickness of the viscoelastic layer. For the parameters under study, the nature of the peak values is analyzed and ways of influencing their position and shape are discussed. It is assumed that such beams can find wide application in antenna technology, since they will significantly reduce mechanical resonant vibrations of antenna system structures, while maintaining their rigidity and strength.