Temperature-dependent hyperelastic behavior of EPDM rubber based on digital image correlation

Abstract This study investigates the characterization and modeling of the temperature-dependent hyperelastic response of Ethylene Propylene Diene Monomer (EPDM) rubber. Initially, The uniaxial tensile strain fields of EPDM rubber at different temperatures were measured using the Digital Image Correlation (DIC) method. Then, The failure modes of EPDM rubber at these temperatures were further investigated using Scanning Electron Microscopy (SEM). The experimental results show that with increasing temperature, the EPDM rubber first becomes softer and then harder. Meanwhile, the fracture mechanism shifts in the direction from ductile to viscous and then to brittle. Compared with the classical Mooney-Rivlin model, the improved one shows a 65% reduction in the mean absolute percentage error (MAPE) for fitting the tensile data of EPDM rubber at room temperature. Therefore, the improved Mooney-Rivlin model was adopted to characterize the hyperelastic behavior of EPDM rubber. Subsequently, the model parameters were extended with a temperature-dependent term. Based on the experimental results, the model parameters were expressed as a quadratic function of temperature. Finally, comparison of the model predictions with the experimental data showed that the coefficient of determination (R 2 ) exceeded 98.7% and MAPE remains below 5.5%, validating the accuracy of the proposed model.