Experimental investigation of the Mullins effect in swollen elastomers

ABSTRACT: Natural rubber distinguishes itself by its particular mechanical properties. It has become an al-most irreplaceable important component part in industrial applications such as vibration isolator, sealing system, flexible piping or structural bearing. During the service, these components are subjected to fluctuating mechan-ical loading. Under cyclic loading conditions, rubber exhibits strong inelastic responses such as stress-softening due to Mullins effect. It is believed that such inelastic response plays major role in determining the durability in service of rubber component. In engineering applications where the components are concurrently exposed to aggressive solvent, further material degradation in the form of swelling occurs. Thus, it is essential to inves-tigate the effect of swelling on the stress-softening due to Mullins effect in rubber like materials for durability analysis. In this study, the Mullins effect in swollen carbon black-filled natural rubber under cyclic loading con-ditions is investigated. The swollen rubbers are obtained by immersing initially dry rubber in solvent at room temperature for various immersion durations. The stress-strain responses for both dry and swollen rubber are found qualitatively similar. However, the stress-softening in swollen rubbers are notably lower compared to that in the dry one. This work is later extended for future modelling purpose by adapting the concept of Continuu