Effects of multi-scale viscoelasticity of polymers on high-pressure, high-frequency sealing dynamics

Viscoelastic effects on the performance of a hydraulic rod seal are examined using a visco-elastohydrodynamic model. The model consists of coupled macro and micro scale deformation and contact mechanics analyses and micro scale fluid mechanics analysis. Dynamic mechanical analysis and a constrained optimization method are used to extract the spectrum of relaxation time scales and corresponding instantaneous elastic moduli associated with the seal polymer, required by the model. Simulation results show that the seal performance, including leakage prevention and friction force, depends on the relationship between the characteristic time constants of the polymer’s molecular chains and the seal cycle frequency.