Investigation on failure properties and constitutive modeling of EPDM used for pulse separation device

Abstract

In order to characterize the rate-dependent deformation-failure behavior of pulse separation device (PSD) of ethylene propylene diene monomer (EPDM), uniaxial constant rate tension, variable rate tension, and stress relaxation experiments were conducted for EPDM in a universal testing machine. It was found that the deformation-failure behavior of EPDM was dependent on the applied strain rates. An improved hyper-viscoelastic constitutive model with an energy limiter (in which the constant energy limiter was replaced by a rate-dependent energy limiter) was proposed to predict the rate-dependent deformation-failure behavior of EPDM under quasi-static loading. The proposed model was first calibrated by fitting it (based on the least squares method) to the data obtained from uniaxial constant rate tension experiments and then further examined by the data obtained from variable rate tension and stress relaxation experiments. The comparative results revealed that the constitutive model with a rate-dependent energy limiter predicted the rate-dependent deformation-failure behavior of EPDM under finite deformation and quasi-static loadings very well.