Dynamic Modelling of a Hydraulic Engine Mount Including the Effects of Elastomer Ageing

In this article, the effect of material ageing of an elastomeric main spring (MS) inside a hydraulic engine mount (HEM) on its dynamic performance is investigated. A set of HEMs aged under realistic operational conditions are used to create an empirical material ageing model of the elastomer at two different temperatures (35 degrees C and 95 degrees C) using dynamic mechanical thermal analysis (DMTA). These ageing models are then coupled to a multibody system (MBS) model of the HEM such that the output simulates variations of the dynamic stiffness, damping, and transmissibility against age (defined as vehicle distance travelled) and the operating engine frequency at these temperatures. The simulation results represent how the dynamic performance of the HEM deviates from its original design with age and how the transmitted force from the engine to the chassis (which is considered as a key indicator for vehicle ride comfort) varies with age, engine frequency, and temperature. This provides new information and knowledge on the dynamic performance of the vehicle as the HEM ages under realistic operating conditions.