Path dependent high strain, strain-rate deformation of polymer toroidal elements

• Published in: Journal of applied physics 2014-08, Vol.116 (8)
• Main Authors: Lee, Chien-Wei, Nesterenko, Vitali F.
• Format: Article
• Language: English
• Subjects: Applied physics; Deformation mechanisms; Dependence; Dynamic models; Dynamic response; O ring seals; Rubber; Stiffness; Strain rate; Viscoelasticity
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4893369

The dynamic behavior of toroidal elements (o-rings) is investigated at the range of global engineering strains up to 0.7 and strain rates about 100 s−1. It was observed that the corresponding average dynamic stiffness of rubber toroidal elements increases up to 3 times in comparison with their quasistatic compression. The viscoelastic dynamic model using linear strain-rate dependence and Hertz damped model did not satisfactory agree with experimental data in investigated range of strains and strain-rates. In order to reflect experimental results, a modified viscoelastic model with power-law strain-rate dependence was proposed. Path dependent deformation of o-rings with different levels of pre-compression was investigated under dynamic loading conditions. It was found that dynamic response of pre-compressed o-rings at the initial strain range of 0.04–0.25 is similar to the behavior of uncompressed o-rings, but further increasing pre-compression to 0.4 and 0.5 results in different force-strain curves demonstrating memory effect. This phenomenon is explained using a model incorporating dependence of dynamic force on initial pre-compression introducing critical level of dynamic strain, after which memory of initial pre-compression fades. This model predicts that force history of weakly compressed o-rings (initial strain 4%) on the stage of loading represents an envelope for all other data in agreement with experiments. In all cases, the dynamic behavior was characterized by stiffer force-displacement curves in comparison with quasistatic compression of o-rings.