Research On Competing Failure Modes And Maintenance Decision For Equipment Based On Multivariate Degradation

With the maturity of modern manufacturing technology,the degree of automation and integration of production systems is increasing,and the complexity and specific features of manufacturing equipment are becoming increasingly prominent.The reliability and maintenance of equipment and production systems are receiving increasing attention from academics and industry.In the process of manufacturing,there are often cases where multivariate degradation modes coexist,and different types of degradation modes have different influences,resulting in competing failure phenomena,and the difficulty of related reliability and maintenance decision-making studies is greatly improved.At present,the research on multivariate degradation problems considering competing failure is still not perfect,and there are mainly three shortcomings:(1)In the research on equipment degradation,most of the literature mainly discusses a single degradation process,and fails to fully consider the impact of competing failure phenomena in complex systems or equipment.(2)In the study of multivariate degradation,most of the researchers' work revolves around the dual degradation process of natural degradation and impact failure,and the traditional reliability indicators such as equipment failure rate are usually first chosen to describe natural degradation.The problem of competing failure of concern is limited.(3)In the existing research,the maintenance of systems and equipment is often used as the foothold of the multivariate degradation problem considering competition failure.A large amount of research has focused on the maintenance stage in the production process.Therefore,there is little attention to the indicators of quality and output in the manufacturing stage and sales stage,such as product manufacturing quality and processing time.More extensive research should be carried out.Aiming at the deficiency of existing research,the main research work of this paper includes:First,a degradation model that considers the phenomenon of competing failure is established.In this paper,the degradation process of the equipment is firstly modeled by the Gamma process,and the cumulative distribution function is used to derive the point at which the specific degradation phenomenon fails.Then the degradation shift model is deduced by the degradation shift topological graph,and it is transformed into the failure time sequence according to the actual situation.Finally,two degradation processes of known-parameter Gamma distribution are used to prove the model.Secondly,the maintenance decision and optimization modeling for single equipment considering multivariate degradation is completed.Based on the established competing failure model,this paper comprehensively considers the quality loss caused by manufacturing quality degradation and the change of production caused by processing time degradation,and combines the failure limitation strategy to build an average profit model that is more in line with actual production conditions.The proposed decision model is tested by a set of actual machining center milling experimental data.Finally,the maintenance decision and optimization modeling for multiple devices considering multivariate degradation is further expanded.A multi-device system is introduced to the opportunistic maintenance strategy,and the decision-making model is constructed.Based on the work completed in Chapters 3 and 4,a serial system consisting of three devices is taken as an example to verify.The research in this paper will introduce more practical engineering problems considering the multi-degraded competing failure phenomenon.Based on the perspective of production management,combined with the focus of equipment management,quality management and efficiency management,this paper proposes a research idea that can cover the multiproduction stage of “manufacturing-maintenance-output”,which has the dual meaning of theoretical and practical guidance.