Abstract In this study, the radiation dose effect of γ 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 °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.

中文翻译：

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γ-辐照对聚甲基乙烯基硅橡胶泡沫不同温度力学行为的影响

摘要 本研究通过单轴压缩试验研究了γ射线对聚甲基乙烯基硅橡胶泡沫随温度变化的力学行为的辐射剂量效应。在室温下暴露于 0 至 500 kGy 的宽辐射剂量范围后，硅橡胶泡沫在 10、40、70 和 100 °C 下进行了测试。测试结果表明，由于硅橡胶基体的主要熵相关变形，温度升高导致未辐照和辐照样品的线性硬化。此外，由于橡胶网络的交联反应占主导地位，辐照剂量的增加导致线性硬化。引入应力硬化因子来表征辐射剂量对温度相关硬化行为的影响，它被定义为给定压缩应变下辐照和未辐照样品的压缩应力之比。每个辐射剂量条件的近似恒定应力硬化因子意味着辐射剂量不会影响与温度相关的硬化行为。根据测试结果，通过将初始剪切模量相关模型参数与辐射剂量和温度相关联，扩展了 Ogden Hyperfoam 模型。与硬化指数相关的模型参数已被证明与辐射剂量和温度无关，并且对于材料的高孔隙率，与泊松比相关的模型参数近似为零。通过在研究的辐照剂量和温度范围内将拟合模型响应与测试数据进行比较，证明了扩展模型的预测性能。研究结果有望对核工程结构的安全评价有所帮助。