On the Realisation of GHM Models in Viscoelasticity

A useful method of modeling viscoelastic effects in structures for transient response analysis is to treat the frequency dependence of the usual damping model through the introduction of extra dissipation co-ordinates. These new co-ordinates require a curve fit to loss factor data over a range of frequencies. One such method called the Golla-Hughes McTavish method, or GHM method, is examined here. The standard GHM approach has only three parameters per second order term in the approximation to the material properties, whereas the four parameters used in this paper gives the most general curve fit. Thus, for the same number of extra degrees of freedom, more accurate predictions from a finite element model with viscoelastic components is possible. This paper also reformulates the series used in the GHM modeling in terms of the high frequency stiffness, rather than the standard low frequency stiffness.