Influence of y-irradiation on mechanical behaviors of poly methyl-vinyl silicone rubber foams at different temperatures

摘要

In this study, the radiation dose effect of gamma rays on the temperature-dependent mechanical behaviors of poly methyl-vinyl silicone rubber foams is investigated by uniaxial compression tests. After exposure to a wide radiation dose range from 0 to 500 kGy at room temperature, silicone rubber foams were tested at 10, 40, 70, and 100 degrees C. The test results show that temperature increase causes linear hardening for both unirradiated and irradiated samples due to the predominating entropy-related deformation of silicone rubber matrix. Moreover, increase of irradiation dose leads to linear hardening as a result of dominating cross-linking reactions of rubber networks. A stress hardening factor is introduced to characterize the effect of irradiation dose on temperature-related hardening behavior, which is defined as the ratio between the compressive stresses of irradiated and unirradiated samples for a given compression strain. The approximated constant stress hardening factor for each radiation dose condition implies that the irradiation dose does not affect the temperature-related hardening behavior. Based on the test findings, the Ogden Hyperfoam model was extended by correlating the initial shear modulus-related model parameters with radiation dose and temperature. The hardening exponent-related model parameters have been shown to be independent of radiation dose and temperature, and the Poisson's ratio-related model parameters are approximated to zero for the high porosity of the material. The prediction performance of the extended model is demonstrated by comparing the fitted model responses with test data over the studied irradiation doses and temperature range. The results are expected to be helpful for the safety evaluation of nuclear engineering structures.