Monotonic and cyclic compressive behaviour of elastomers

The present paper describes the changes in stress response that take place during the monotonic and cyclic deformation of elastomers. Cyclic compressi on testing was carried out to determine the elastomer's response under simu lated service conditions. The stress changes were monitored continually. Fo r a given uniaxial cyclic strain, the maximum equivalent stress decreased w ith cycles. Under conditions of two-dimensional cyclic strain, the stress r esponse was higher and the changes occurred in two stages. Initially, the s tress decayed quickly, then more slowly as strain cycling continued. This f irst stage was associated with viscoelastic effects. After a relatively sta ble period, the stress began to decrease again at a progressively faster ra te as the end of the design life approached. This second stage was related to microstructural damage caused by bond failure. The total stress reductio n is described by a two stage model, which combines the viscoelastic and da mage effects. PRCPA/1402 (C) 1998 The Institute of Materials.