Application of the network alteration theory for modeling the time-dependent constitutive behaviour of rubbers.: Part II. Further evaluation of the general theory and experimental verification

Abstract

In part I of this paper (E.G. Septanika, L.J. Ernst, 1998. Application of the network alteration theory for modeling the time-dependent constitutive behaviour of rubbers. Part I. General theory. Mech. Mater. 30, 253–263), a general time-dependent constitutive model for rubber materials has been developed, based on combination of the general rubber hyperelastic theory and the microstructure alteration theory. Besides, Mullin's effect is included into the model by employing Simo's rubber hysteresis theory. In this second article a further evaluation of the developed model is presented. First, the eight non-Gaussian chain model of Arruda and Boyce is chosen to describe the rubber hyperelastic behaviour. Second, the full range of the alteration process is described using a general reaction law. The experimental characterization of both the time-independent and the time dependent parameters is performed for a modified Natural Indonesian Rubber (modified SI-Rubber). Finally, numerical examples are presented to illustrate the capability of the proposed model. It appears that the present model is capable of describing the time dependent irreversible deformation behaviour of rubber-like materials, i.e. large (irreversible) deformation, stress-relaxation, creep, permanent set and aging induced flexibility changes.