Study On Dynamic Leasing Oriented Preventive Maintenance Policy

As the equipment becoming more and more advanced,automatic and sophisticated,it comes a significant increase in the acquisition cost,naturally,entreprises are less willing to purchase the equipment for the short-term using.Consequently,a new mode of equipment management is rising gradually,in which the equipment leasing takes the place of equipment procurement,and the leasing maintenance service provided by the lessors takes the place of the traditional autonomous maintenance provided by the lessees.For the shortterm dynamic leasing of the durable equipment,how to provide a reasonable and effective preventive maintenance policy with the consideration of differentiated leasing environment characteristics,as well as the equipment reliability requirement and the maintenance costs reduction,has become urgent for the equipment leasing service providers.From the perspective of equipment lessor facing the dynamic leasing condition,this paper makes a comprehensive analysis of the reliability deteriorating characteristics including continuous internal degradation and stochastic external shock damage,then it goes into a deep study of the flexible preventive maintenance policy.The specific content is as follows: Firstly,compared with some traditional leasing modes,the reliability deteriorating process of dynamic leasing equipment has an interaction between the internal degradation and the external shock damage,therefore,the special requirements of reliability assessment and preventive maintenance are proposed.Secondly,introducing the two-factor imperfect maintenance mechanism,the failure recovery factor and the failure increasing factor are redefined,which shows the correlation between leasing environment,equipment failure state and preventive maintenance effort.Then,the internal-external mixed failure model for dynamic leasing equipment is established.The numerical analysis convinced its validity by observing the failure evolution trend.Finally,the flexible preventive maintenance policy is proposed considering the failure state of leasing equipment and the dynamic changing leasing environment.With the target of minimizing the operation and maintenance cost rate,some numerical examples,based on the PM cost decision model,are given to validate the flexibility and economical efficiency of the proposed PM policy.The result shows that the flexible PM policy has a significant advantage in the phased PM decision for long-term leasing,besides,it can be applied for the decision of dynamic leasing scheduling.In conclusion,this paper conducted a relatively complete study in the failure deteriorating mechanism and the flexible PM policy for the dynamic leasing equipment,which makes a little contribution to the development of equipment maintenance theory.The research result can provide a technical support for the equipment lessors to improve their PM decision efficiency.