Viscoelastic effects in a spherical Gravitational Wave antenna

TL;DR

This paper investigates how internal friction and viscoelastic properties affect the resonance behavior and quality factors of spherical gravitational wave detectors, providing models for different material assumptions.

Contribution

It introduces models for viscoelastic effects in spherical GW detectors and analyzes how these effects influence mode quality factors across various assumptions.

Findings

Quality factor depends on mode frequency under different material models

Viscoelastic effects cause exponential damping of eigenmodes

Discussion on applicability to real detectors

Abstract

Internal friction effects are responsible for line widening of the resonance frequencies in spherical gravitational wave detectors, and result in exponentially damped oscillations of its eigenmodes with a decay time which is proportional to the quality factor of the mode and to its inverse frequency. We study the solutions to the equations of motion for a viscoelastic spherical GW detector based on various different assumptions about the material's constituent equations. Quality factor dependence on mode frequency is determined in each case, and a discussion of its applicability to actual detectors is made.