During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and two ageing temperatures of \(125\,^{\circ }\,\hbox {C}\) and \(150\,^{\circ }\, \hbox {C}\). To exclude possible diffusion-limited oxidation (DLO) effects that can distort the data, IRHD microhardness measurements were taken over the cross section of compressed O-rings. Continuous stress relaxation measurements were taken on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments.

在 Bundesanstalt für Materialforschung und prüfung 进行的一项广泛的测试计划中，研究了 EPDM O 型圈在不同老化时间和两个老化温度\(125\,^{\circ }\,\hbox {C}\ )和\(150\,^{\circ }\, \hbox {C}\). 为了排除可能会扭曲数据的扩散限制氧化 (DLO) 效应，IRHD 显微硬度测量是在压缩 O 形环的横截面上进行的。对没有 DLO 影响的样品进行连续应力松弛测量。在长期热暴露期间，物理过程对不可逆化学过程的附加影响通过分析各种测试条件下的压缩永久变形测量值来量化。通过结合不同的实验方法，确定了与降解过程相关的特征时间。在实验数据的基础上，开发了一种考虑可逆和不可逆过程的微观物理模型。材料模型的参数识别策略基于我们对均质老化弹性体 O 型圈的实验研究。模拟结果与实验吻合较好。