Joint Optimization Of Maintenance Strategy And Sampling Scheme Based On Stochastic Degradation Production Syste

Quality control and maintenance strategy are two important issues in manufacturing system.During the operation of the production system,due to aging,environmental change,component failure and other factors,the production system will break down or the quality of the processed products will deteriorate.If the abnormal state of the production system is not discovered and corrected in time,it will result in production loss.Therefore,it is very important to monitor and maintain the running state of production system in time.Aiming at the random degradation production system,this thesis studies from the following aspects.First,the joint optimization of lot size and productivity under two maintenance strategies,preventive maintenance and corrective maintenance,was studied under the condition of fixed market demand rate.According to the running state of the system,the production process is divided into two situations.The total cost of the two cases was calculated by considering the scrap cost of defective products,inventory holding cost,preventive maintenance cost,corrective maintenance cost,product supply loss,product inspection classification cost,etc.Under the condition that the two kinds of maintenance time obey Weibull distribution,the average profit per unit time model is constructed,and the production plan optimization scheme is proposed to maximize the profit.Secondly,considering that there are two failure modes of abnormal and failure in the operation process of the production system,mid-term inspection is carried out on the production system in the case that system exceptions can only be found through inspection.When the system is abnormal,the system can be restored to the pre-abnormal state through minimum maintenance.Minimum maintenance does not change the age of the system.If the system is not abnormal,maintenance is not performed on the production system.It is assumed that the time of abnormal occurrence and failure in the production system are independent of each other and obey the Weibull distribution.According to the operating state of the system in different intervals,the average profit per unit time under each operating state is discussed respectively,and the average profit model with lot size,interim inspection time and sampling scheme as decision variables is established.Finally,the feasibility of the model is verified by numerical analysis,and the influence of model parameters on the optimal decision scheme is discussed by sensitivity analysis.