Hydraulic system has a critical and important role in drilling machines.Any failure in this system leads to problems in power system and machine operation.Since the failure cannot be prevented entirely,it is important...Hydraulic system has a critical and important role in drilling machines.Any failure in this system leads to problems in power system and machine operation.Since the failure cannot be prevented entirely,it is important to minimize its probability.Reliability is one of the most effcient and important method to study safe operation probability of hydraulic systems.In this research,the reliability of hydraulic system of four rotary drilling machines in Sarcheshmeh Copper Mine in Iran has been analyzed.The data analysis shows that the time between failures(TBF)of Machines A and C obey the Weibull(2P)and Weibull(3P)distribution,respectively.Also,the TBF of Machines B and D obey the lognormal distribution.With regard to reliability plots of hydraulic systems,preventive reliability-based maintenance time intervals for 80%reliability levels for machines in this system are 10 h.展开更多
In order to solve the best maintenance interval problem of the elevator hydraulic actuation systems on civil aircraft, a method based on reliability and cost minimum is introduced in this paper. The estimation of syst...In order to solve the best maintenance interval problem of the elevator hydraulic actuation systems on civil aircraft, a method based on reliability and cost minimum is introduced in this paper. The estimation of system reliability is presented by using two-parameter Weibull distributions. The parameters are estimated by using Weibull probability statistical analysis and the practical operational data. Then, the maintenance optimization model isformulated where the objective function is to minimize the expected schedule maintenance cost in a time unit. The results of numerical example show that the proposed model could scheme the optimal maintenance intervals for the considered system when the parameters are given. This research has certain significance in theoryand engineering practice.展开更多
The hydraulic system plays an important role in supplying power and its transition to other working parts of a coal shearer machine. In this paper, the reliability of the hydraulic system of a drum shearer was analyze...The hydraulic system plays an important role in supplying power and its transition to other working parts of a coal shearer machine. In this paper, the reliability of the hydraulic system of a drum shearer was analyzed. A case study was done in the Tabas Coal Mine in Iran for failure data collection. The results of the statistical analysis show that the time between failures （TBF） data of this system followed the 3-parameters Weibull distribution. There is about a 54% chance that the hydraulic system of the drum shearer will not fail for the first 50 h of operation. The developed model shows that the reliability of the hydraulic system reduces to a zero value after approximately 1 650 hours of operation. The failure rate of this system decreases when time increases. Therefore, corrective maintenance （run-to-t^ailure） was selected as the best maintenance strategy for it.展开更多
基金the R&D center of Iranian National Copper Company for its financial support
文摘Hydraulic system has a critical and important role in drilling machines.Any failure in this system leads to problems in power system and machine operation.Since the failure cannot be prevented entirely,it is important to minimize its probability.Reliability is one of the most effcient and important method to study safe operation probability of hydraulic systems.In this research,the reliability of hydraulic system of four rotary drilling machines in Sarcheshmeh Copper Mine in Iran has been analyzed.The data analysis shows that the time between failures(TBF)of Machines A and C obey the Weibull(2P)and Weibull(3P)distribution,respectively.Also,the TBF of Machines B and D obey the lognormal distribution.With regard to reliability plots of hydraulic systems,preventive reliability-based maintenance time intervals for 80%reliability levels for machines in this system are 10 h.
文摘In order to solve the best maintenance interval problem of the elevator hydraulic actuation systems on civil aircraft, a method based on reliability and cost minimum is introduced in this paper. The estimation of system reliability is presented by using two-parameter Weibull distributions. The parameters are estimated by using Weibull probability statistical analysis and the practical operational data. Then, the maintenance optimization model isformulated where the objective function is to minimize the expected schedule maintenance cost in a time unit. The results of numerical example show that the proposed model could scheme the optimal maintenance intervals for the considered system when the parameters are given. This research has certain significance in theoryand engineering practice.
文摘The hydraulic system plays an important role in supplying power and its transition to other working parts of a coal shearer machine. In this paper, the reliability of the hydraulic system of a drum shearer was analyzed. A case study was done in the Tabas Coal Mine in Iran for failure data collection. The results of the statistical analysis show that the time between failures （TBF） data of this system followed the 3-parameters Weibull distribution. There is about a 54% chance that the hydraulic system of the drum shearer will not fail for the first 50 h of operation. The developed model shows that the reliability of the hydraulic system reduces to a zero value after approximately 1 650 hours of operation. The failure rate of this system decreases when time increases. Therefore, corrective maintenance （run-to-t^ailure） was selected as the best maintenance strategy for it.
