Advanced characterization of the damping dynamics of silicone elastomers and natural rubber using the instrumented rebound resilience tester

This study investigates the relationship between rebound resilience (RR) and damping dynamics in elastomers using an instrumented pendulum impact tester. Four materials, three silicone elastomers and one natural rubber (NR), with varying Shore hardnesses from 00 to 10 to A50 were examined. The materials were chosen to compare silicone elastomers, specifically poly(dimethylsiloxane) (PDMS), at different hardness levels to standard NR, known for its good vibration damping, high tensile strength, and economic advantages but limited durability under severe environmental conditions. PDMS, conversely, offers superior weatherability and broader temperature applicability.
Traditional RR pendulum impact testing yields only discrete resilience values and inadequately describes damping dynamics. Thus, the RR tester was instrumented with a high-speed camera and piezoelectric force sensor to capture detailed impact forces and dissipation energies, providing comprehensive insights into rebound dynamics. Three distinct phases of pendulum motion were analyzed: initial deflection αinitial at time tinitial, impact αimpact at timpact, and maximum rebound height αrebound at trebound.
Results confirm that RR inversely correlates with mechanical damping; however, elastomers with similar RR values displayed significantly different force profiles due to distinct damping dynamics. The results reveal that the softest silicone (Ecoflex 00–10) and NR exhibited similar RR (∼0.33) but significant different impact forces (85 N vs. 656 N). Impact duration and force were influenced by hardness and macroscopic deformation under impact. These findings challenge the traditional hardness-damping relationship and provide a framework for elastomer characterization in dynamic applications.