Analysis of the service life and reliability of a certain type O silicone rubber seal

Abstract

To investigate the aging behavior of silicone rubber O-rings under humid-heat stress and evaluate their storage life and reliability, a specific silicone rubber O-ring was taken as the research object. Accelerated humid-heat aging tests were carried out at 20% and 30% compression levels, respectively. Using the compression set rate as the performance degradation indicator, a nonlinear aging kinetic model was established. The Peck model was adopted to predict the storage life under coupled temperature and humidity stress, and a two-parameter Weibull distribution was used to conduct reliability analysis, so as to obtain the reliable life, 95% confidence interval, and reliability evolution law. In addition to the compression set, residual deformation after stress release was analyzed to evaluate the elastic recovery capability of silicone rubber and its influence on long-term sealing reliability. The results show that temperature is the dominant driving factor for the humid-heat aging of O-rings. Under the storage condition of 25 ℃ and 50% RH, the predicted storage life is 6.72 years for O-rings with 20% compression and 5.86 years for those with 30% compression. The goodness-of-fit R2 of the Weibull distribution is greater than 0.96, indicating that the O-rings present typical wear-out failure characteristics. The 95% confidence intervals are of low dispersion, verifying that the prediction results are stable and reliable.