Reliability Analysis And Dynamic Maintenance Str Ategy Research Of Mechanical Systems Considering D Egradation And Shock Effects

The integration,digitization and intellectualization of mechanical equipment has become an irresistible trend of development,which puts forward higher and higher requirements for system reliability evaluation and maintenance decision-making.How to achieve effective reliability evaluation and maintenance decision-making of complex mechanical systems has become an important research topic.Based on the statistical model,this thesis takes the mechanical system undergoing both natural degradation process and external random shock process as the object,and studies the system reliability and dynamic maintenance under the interaction of degradation process and shock process,which has important theoretical significance and application value.The degradation and shock failure types of mechanical system are studied,and a failure process model considering degradation and shock effect was established.Gamma and Wiener stochastic process models were used to model the natural degradation process of system components.The impact of external random shocks on system components is modeled by using the ideas of extreme shock model and cumulative shock model.On the one hand,random shocks can accelerate the natural degradation process by increasing the degradation increment;on the other hand,the change of the degradation state of system components can affect the impact failure rate of random shocks.The reliability analysis model of mechanical system with serial and parallel configuration of components was established,analyzed the probability of component failure,and designed a system reliability simulation algorithm.Taking the spool valve system with two components in series as an example,the influence of different degradation rates and impact rates on system reliability was analyzed through component degradation path simulation and system reliability simulation,and the effectiveness of the system reliability model considering degradation and impact effects was verified.A dynamic maintenance model based on the strategy of "dynamic detection period-variable maintenance threshold" was established.Through the maintenance cost analysis,with the minimum maintenance cost rate as the goal,a condition-based optimization model of the mechanical system maintenance process was established,and a Monte Carlo algorithm was designed,which could effectively obtain the detection cycle of the next maintenance activity and preventive maintenance threshold of each component according to the degradation state of the system components.Taking the spool valve system as an example,through the degradation path simulation and maintenance optimization model solving,the system dynamic maintenance process diagram is formed,and the impact of system maintenance cost changes on maintenance activities was analyzed.