In practical engineering,sometimes the probability density functions( PDFs) of stress and strength can not be exactly determined,or only limited experiment data are available. In these cases,the traditional stress-str...In practical engineering,sometimes the probability density functions( PDFs) of stress and strength can not be exactly determined,or only limited experiment data are available. In these cases,the traditional stress-strength interference( SSI) model based on classical probabilistic approach can not be used to evaluate reliabilities of components. To solve this issue, the traditional universal generating function( UGF) is introduced and then it is extended to represent the discrete interval-valued random variable.Based on the extended UGF,an improved discrete interval-valued SSI model is proposed, which has higher calculation precision compared with the existing methods. Finally,an illustrative case is given to demonstrate the validity of the proposed model.展开更多
At present, universal generating function(UGF) is a reliability evaluation technique which holds the bare-looking and easily program-realized merits in multi-state system. Thus, it is meaningful to apply this method t...At present, universal generating function(UGF) is a reliability evaluation technique which holds the bare-looking and easily program-realized merits in multi-state system. Thus, it is meaningful to apply this method to an actual industry system. Compressor systems in natural gas pipelines are series-parallel multi-state systems,where the compressor units in each compressor station work in a parallel way and these pressure-boosting stations in the pipeline are series connected. Considering the characteristic of gas pipelines, this paper develops two different UGFs to evaluate the system reliability. One(Model 1) establishes a system model from every compressor unit while the other(Model 2) considers the whole system as a combination of multi-state components. Besides, all the parameters of "weight" in UGFs are obtained from thermal-hydraulic models based on the actual engineering and"probability" from Monte Carlo simulation. The results show that the system reliabilities calculated by different UGFs are approximately equal. In addition, the demand of gas and the gas pipeline transportation system show a reverse trend. Because the number of parameters needed in Model 2 is far less than that needed in Model 1,Model 2 is simpler programming and faster solved.展开更多
The availability equivalence of different designs for a repairable multi-state series-parallel system(RMSPS) is discussed in this paper.The system components are assumed to be independent,and their failure and repair ...The availability equivalence of different designs for a repairable multi-state series-parallel system(RMSPS) is discussed in this paper.The system components are assumed to be independent,and their failure and repair rates to be constant.The system availability is defined as the ability of the system to satisfy consumer demand.Factor improvement method and standby redundancy method are used to improve the system design.To evaluate availability of the both original and improved systems,a fast technique,based on universal generating function,is adopted.The availability equivalence factor is introduced to compare different system designs.Two types of availability equivalence factors of the system are derived.A numerical example is provided to illustrate how to utilize the obtained results.展开更多
基金National Natural Science Foundation of China(No.51265025)
文摘In practical engineering,sometimes the probability density functions( PDFs) of stress and strength can not be exactly determined,or only limited experiment data are available. In these cases,the traditional stress-strength interference( SSI) model based on classical probabilistic approach can not be used to evaluate reliabilities of components. To solve this issue, the traditional universal generating function( UGF) is introduced and then it is extended to represent the discrete interval-valued random variable.Based on the extended UGF,an improved discrete interval-valued SSI model is proposed, which has higher calculation precision compared with the existing methods. Finally,an illustrative case is given to demonstrate the validity of the proposed model.
基金the National Natural Science Foundation of China(No.51504271)the National Science & Technology Specific Project(No.2016ZX05066005-001)
文摘At present, universal generating function(UGF) is a reliability evaluation technique which holds the bare-looking and easily program-realized merits in multi-state system. Thus, it is meaningful to apply this method to an actual industry system. Compressor systems in natural gas pipelines are series-parallel multi-state systems,where the compressor units in each compressor station work in a parallel way and these pressure-boosting stations in the pipeline are series connected. Considering the characteristic of gas pipelines, this paper develops two different UGFs to evaluate the system reliability. One(Model 1) establishes a system model from every compressor unit while the other(Model 2) considers the whole system as a combination of multi-state components. Besides, all the parameters of "weight" in UGFs are obtained from thermal-hydraulic models based on the actual engineering and"probability" from Monte Carlo simulation. The results show that the system reliabilities calculated by different UGFs are approximately equal. In addition, the demand of gas and the gas pipeline transportation system show a reverse trend. Because the number of parameters needed in Model 2 is far less than that needed in Model 1,Model 2 is simpler programming and faster solved.
基金supported in part by the Natural Science Foundation of Hebei Province under Grant Nos.A2014203096 and G2012203136the National Natural Science Foundation of China under Grant No.11201408the Science Research Project of Yanshan University under Grant No.13LGA017
文摘The availability equivalence of different designs for a repairable multi-state series-parallel system(RMSPS) is discussed in this paper.The system components are assumed to be independent,and their failure and repair rates to be constant.The system availability is defined as the ability of the system to satisfy consumer demand.Factor improvement method and standby redundancy method are used to improve the system design.To evaluate availability of the both original and improved systems,a fast technique,based on universal generating function,is adopted.The availability equivalence factor is introduced to compare different system designs.Two types of availability equivalence factors of the system are derived.A numerical example is provided to illustrate how to utilize the obtained results.
