Abstract:

In order to predict remaining life of submarine pipelines and optimize maintenance cost, a maintenance strategy modeling method was proposed based on Gamma process residual life prediction under accelerated stress degradation test. The data of pipeline corrosion and degradation were obtained by temperature and pressure double stress accelerated degradation experiment, and their residual life prediction model was established by using Gamma process. Relationship between average life and stress of pipelines was reflected by generalized Eyring model, and maximum likelihood method was used to estimate model parameters as a whole. Then, a maintenance decision optimization model aiming at minimum expected cost ratio was developed to determine optimal maintenance times and expected consume ratio (ECR). Finally, with N80 pipeline as an example, the effectiveness and correctness of residual life prediction and maintenance model were verified. The results show that the use of accelerated degradation test can greatly shorten data acquisition time. And according to the optimized maintenance model based on remaining life, the optimal times for maintenance is 7 and minimum expected cost rate is 4.435 yuan/h.

Key words: submarine corrosion pipeline, remaining life prediction, maintenance strategy, Gamma process, generalized Eyring model