Li Changyou

Gradual Reliability Sensitivity Analysis of Mechanical Part Considering Preventive Maintenance

A lot of mechanical parts are subject to failure due to the deterioration. Usually the preventive maintenance is taken to ensure the safety and reliability. Therefore, it is very important to study the gradual reliability design of the mechanical part for improving the gradual reliability of the mechanical system under the condition of considering the preventive maintenance. Beta distribution is employed to describe the randomness of the mechanical part state after the preventive maintenance. The deterioration process of the mechanical part is modeled using the nonstationary Gamma process. The gradual reliability model before the first preventive maintenance is proposed according to the gradual failure principle and using the initial state distribution and the properties of Gamma process. Then, the gradual reliability model between any two times of preventive maintenance is also derived. Subsequently, the sensitivity equations of the proposed gradual reliability model to each parameter are given. The application process and practicality of the proposed approach are described by a numerical example. This work solved the problem where the maintenance has not been well considered in the reliability design of the mechanical part and contributed to the theory and method of improving the safety and reliability operation of the mechanical system.

Notice of Retraction Design of castor shucking machine key component and study on parameter optimization experiment

Through the study on the shucking principle of castor shucking machine, this paper designs the key working mechanism of castor shucking machine. By orthogonal experiment, it finds that the main parameters influencing the rate of insufficient shucking and breakage rate are roller speed, gap and material and studies the influence degree of various parameters on shucking effect and the relationship between them in the process of shucking. Shucking net rate: the influence of roller speed and gap on it is relatively significant but the influence of roller material on it is not significant; breakage rate: the influence of roller speed, gap and material on it is significant. The best optimization combination is A2B2C3, i.e. shucking roller speed is 10r/min, shucking roller gap is 18mm and shucking roller material is steel base covered with plastic material outside.

Notice of Retraction Reliability assessment of the system subjected to sudden and multiclass gradual failures

There are many systems which undergo not only sudden failure but also multiclass gradual failures simultaneously. This paper presents an approach to reliability assessment of these systems. Firstly, the system reliability model is given. The sudden failure time is assumed to follow the two-parameter Weibull distribution and the distribution is real-timely updated by the Bayesian estimation approach, and then the reliability model of the system subjected only to sudden failure is obtained. The deterioration of a variable leading to one class of gradual failure is described by a Gamma process and the parameters are real-timely updated by the Bayesian estimation approach, and then the reliability model of the system subjected only to one class of gradual failure is formulated. The results of the numerical example show that the proposed approach is effective for the reliability assessment of the system subjected to sudden and multiclass gradual failure simultaneously.