Abstract:

In practical application, the safety-related relays for urban rail vehicles generally do not fail, making it difficult to analyze and evaluate the distribution of their life using common methods. Two methods are proposed for estimating the reliability of relays in the absence of failure data. One method involves using non-parametric methods to transform the problem of estimating the distribution parameters into a binomial distribution under unknown distribution conditions, in order to estimate the lower confidence limit of reliability. The other method assumes unknown shape parameters of the Weibull distribution and uses engineering experience to estimate the lower confidence limit of reliability. The feasibility and effectiveness of the proposed methods are demonstrated through example calculations, and the calculation errors are compared and analyzed. The application of this approach can effectively evaluate the reliability level of relays under actual operating conditions, providing the assurance for the safe and reliable operation of vehicles.

Key words: urban rail, relay, no failure data, reliability assessment