ABSTRACT
Since equivalent viscoelastic frequency domain data were used to fit the model its basic form is given by:
′ ′ + ′G G= Ghve ep (1)
′′ ′′ + ′′G G= Ghve ep (2)
where G′ and G″ are the storage and loss modulus respectively and the subscripts hve and ep refer to the elastoplastic and hyper-viscoelastic components of the model respectively. G′ and G″ are given in terms of the complex modulus, G*, and loss angle, δ, by the usual equations:
′G G= *cosδ (3)
1 INTRODUCTION
Following Austrell (1997), a model for filled rubber was proposed which consists of hyperelastic, visco-elastic and elastoplastic components in parallel (Ahmadi et al., 2008a, Ahmadi & Muhr, 2011). It is readily implemented in commercial FEA codes by means of an overlay of meshes of the constituent materials. The model captures the essence of the behaviour of filled rubber, in particular the Payne or Fletcher-Gent effect, with a small number of physically meaningful parameters which can be fitted either from quasi-static stressstrain tests and a stress relaxation measurement (Ahmadi et al., 2008a) or from equivalent viscoelastic frequency domain data, such as the tables of complex modulus and loss angle as a function of amplitude and temperature provided in EDS data sheets (TARRC 1979-1986, Muhr, 2009). A modification to the model to capture the Mullins effect has been proposed by Kingston & Muhr (2011).
