Predictive model of dynamic properties of elastomers in thermal degradation environment

Abstract

In dynamic systems, numerous structural components, such as mounts, bushings, and tires, deteriorate over time due to environmental conditions. In these elastomers, the typical environmental factor of aging is manifested by the oxidation of polymer chains due to exposure to air. The amount of oxidation in elastomers heavily depends on temperature. Elastomer components under thermal degradation show different dynamic characteristics over time. Predicting the mechanical properties of aged elastomers is crucial in structural design for enduring high-quality noise and vibration. In this work, we propose a procedure for predicting the dynamic properties of elastomers undergoing thermal degradation. This process is divided into 1) an inter-variability analysis in specific degradation states caused by uncertainties in the operational temperature environment, variation in the manufacturing process, and error of the material property model and 2) an analysis of the degradation variability caused by uncertainties in the degradation environment and the degradation model. The degradation variability includes the inter-variability and thus becomes a distribution of distributions. Therefore, the double-loop eigenvector dimension reduction method is proposed to predict degradation variability. The time–temperature superposition principle and an equivalent degradation time are introduced to accumulate the degradation states in case of thermal degradation at various temperatures. The proposed method is applied to a circular mount problem. The numerical results illustrate that the proposed method effectively predicts the aging of the dynamic elastomer properties that is due to the thermal environment.