Reliability Analysis Of Heavy Ammonium Nitrate/Fuel Oil Vehicle Based On Dynamic Fault Tree

With the development of the technology of the heavy ammonium nitrate fuel oil(ANFO)vehicle,the dynamic characteristics of the equipment become remarkable.The traditional fault tree analysis cannot meet the accuracy requirements of the reliability evaluation of the equipment,so it is urgent to carry out in-depth research on the dynamic characteristics.At the same time,the use of reliability analysis results is limited,only to provide reference for system improvement.Therefore,this paper uses the relevant methods of dynamic fault tree research to study the heavy ANFO vehicle.And then uses the analysis results to formulate the search strategy of parts when the system failure occurs,so as to improve the efficiency of failure search.The results show that the failure probability of fuel throttle valve,twoposition four-way electro-hydraulic proportional valve,latex matrix box,sensitizer flowmeter,sensitizer pump and sensitizer filter is high,which is the weak link of the system.When the failure is checked,the sensitizer flexible pipe is in the first level of the failure search strategy,and it is the first component to be checked;the latex matrix pump,the return pipe seal,the latex matrix pump flexible pipe,the latex matrix butterfly valve,the fuel filter and the latex matrix pump joint are in the second level of the failure search strategy.And failure checking is carried out in this order.The core content of this paper includes:(1)Dynamic fault tree modeling and analysis.Through in-depth analysis of equipment structure and principle,parts and logical structure are expressed graphically by using reliability block diagram.This paper chooses the material conveying subsystem of the heavy ANFO vehicle with dynamic characteristics as the research object,and transforms its reliability block diagram into dynamic fault tree model.The dynamic fault tree is analyzed by using the Cut-order method,and 175 failure modes of the material conveying subsystem are determined,which has guiding significance for the redesign of the system logic.(2)Reasoning research based on discrete Bayesian network.Through further model mapping,the dynamic fault tree model is transformed into Bayesian network model.The failure distribution of components is determined by reliability data analysis methods such as historical data fitting.The reliability curves of the material conveying subsystem varying with the task time and the probabilistic importance of components are obtained by using MATLAB modeling and reasoning calculation.The analysis results are of great significance to the improvement of the system.(3)The dynamic fault tree analysis results are used to study the fault search strategy of components in the material conveying subsystem.By using the reliability index of components probabilistic importance,combining the two cost indexes of maintenance people number and maintenance time,the search strategy of 39 components in case of failure is studied.Finally,the components are divided into five search levels,and the search order of the components within every level is determined,which effectively improves the search efficiency of the components when the system fails.