Micromechanically Motivated Model for Oxidation Ageing of Elastomers
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The oxidative ageing behaviour of elastomers is of concern for product lifetime analysis and the prediction of degradation effects such as stress-softening and permanent set. Two main reactions occur during oxidative ageing; chain scission and cross-link formation which result in stress-softening, stiffening and the permanent set effect. In this model, a network dynamics model is introduced to capture the changes in polymer network topology due to chain scission and cross-link formation. The network dynamics are coupled through the shear modulus to a micro-mechanically motivated constitutive model based on the micro-sphere model using a multiplicative decomposition to capture secondary network effects. A novel mapping technique allows the degradation of both the primary and secondary networks to be efficiently handled. Numerical results indicate agreement with experimental results and show improvements over current computational approaches.
The authors would like to kindly acknowledge the funding by the DFG (Deutsche Forschungs Gemeinschaft) in the IRTG1627 framework.
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