Material modeling for numerical simulation of elastomer O-rings with experimental verification at low temperatures

Elastomer O-ring seals are used in many technical applications and their requirements are becoming increasingly challenging for high-pressure applications like hydrogen storage systems. We analyze the performance of such seals at low temperatures and highlight the essential effects of primary leakage. Linear viscoelastic material modeling is described and defined with the help of Dynamic Mechanical Thermal Analysis (DMTA), Time-Temperature Superposition Principle (TTSP), and the shift function of Williams-Landel-Ferry (WLF) by assuming thermo-rheological simple material behavior. Numerical calculations and experimental validation are done for strain-rate dependent uniaxial tensile tests, Temperature Retraction (TR), Compression Set (CS), and specific leakage tests with O-rings. Thanks to Finite Element Analysis (FEA) it is possible to identify the most significant influences on the sealing tightness. Thermal shrinkage and the increasingly limited recovery of elastomer O-rings are mainly responsible for primary leakage at low temperatures and can be enforced by time-temperature dependent stress relaxation and manufacturing tolerances.