Lifetime prediction of the epoxy resin adhesive under the optical performance degradation process

In this study, an epoxy resin adhesive called optically clear resin (OCR) was prepared. The type I (time censored) accelerated degradation tests associated with various temperature-humidity conditions were performed to evaluate the lifetimes of the test vehicle. The optical performance, Yellow index (YI), was used and the failure criterion was defined when the YI reaches a specific value of 2. The test results indicate that the degradation path of test samples represent the brownian motion so that a Weiner process was applied to model the degradation of test samples. A typical Monde Carlo simulation was performed to predict the lifetimes at the threshold level for each test condition. The simulation results present that the lifetimes at the test condition 85°C/85% RH and 75°C/85% RH are 2216 hours and 3322 hours respectively. As the results, the acceleration factor and activation energy was calculated to be 1.5 and 0.6874 ev/K respectively. Furthermore, a bogey test method was used to determine the sample size and failure free test duration according to the specific reliability goal and confidence level.