High Speed Elastomer Resilience

Static elastomeric seals applied within their elastic limits spend their functional life trying to return to their original geometry. Compression stress relaxation measurements quantify this static counterforce and monitor its decay under the combined forces of time, chemical exposure and thermal cycling. This method is a popular and successful tool for ranking a materials likely success for sealing applications under the test conditions. Applications described as static can experience periods of pressure fluctuation or structural vibration resulting in rapid loss of compressive loading due to geometric changes of seal glands. Quantifying a seal’s ability to maintain the necessary counterforce during these geometric changes requires measuring resilience under a time frame and magnitude equal to the conditions affecting the static condition. Seals and other applications requiring rapid response to single or cyclic compressive loading

variations can quantify performance by measuring resilience. High-speed resilience measurements of test specimens during rapid unloading of compressive forces can quantify both the contact force and recovery rate. These measurements show resilience to be polymer specific, temperature dependent and relatively independent of polymer age and initial compression level within elastic limits. Comparing seal counterforce prior to unloading has no correlation with resilience. This illustrates that compression stress relaxation measurements provide no indication of resilience.