Design and analysis of fiber enhanced viscoelastic damping polymers

A new composite damping material is investigated which consists of a viscoelastic matrix and high elastic modulus fiber inclusions. This fiber enhanced viscoelastic damping polymer is intended to be applied to lightweight flexible structures as a surface treatment for passive vibration control. A desirable packing geometry for the composite material is proposed, which Is expected to produce maximum shear strain in the viscoelastic damping matric. Subsequently, a micromechanical model is established in which the effect of fiber segment length and relative motion between neighboring fibers are taken into account. Based on this model closed form expressions for the effective storage and loss properties of the damping material are developed and an optimal relation between design parameters, such as the length, diameter, spacing, and Young's modulus of fibers and the shear modulus of viscoelastic matrix, is derived for achieving maximum damping performance. To address the verification of the development, the theoretical results are compared with NASTRAN finite element results. Upon comparison of an enhanced viscoelastic damping treatment with a conventionally constrained layer damping treatment, it is found that the enhanced polymer provides a significant improvement in damping performance.