The Reliability Simulation And Analysis For Hydraulic Lifting System Of Luffing Tower Crane Based On Fault Tree

Luffing tower crane is a high-risk outdoor specialized facility, which is mainly applied for high-rise building engineering, especially for critical lifting work of large object in special and narrow space. Climbing mechanism is one of the five main parts of luffing tower crane, it lifts or declines the climbing frame in order to increase or decrease standard section, thus, tower crane ascends or descends in accordance with the height of the building, which satisfies the requirement of vertical transportation for buildings of different heights. Hydraulic system is the vital power drive and control source to climbing mechanism, with the help of reversing valve, diesel engine drives pump, pump drives hydraulic oil in order to control the telescopic speed of the cylinder, so the reliability of climbing mechanism has a direct impact on the safety of tower crane. A reliability study based on fault tree analysis of hydraulic system is introduced, which decreased the fault probability of luffing tower crane, in this method, fault position can be predicted, which decreased the fault probability by reacting faster, and increased the reliability and lifetime of tower crane.Firstly, a brief introduction of large-size luffing tower crane is stated in this paper, it includes the basic method and principle of hydraulic system design, and leads to a further discussion of the lifting condition and hydraulic system design on the basis of16000kN·m luffing tower crane; Secondly, it listed a detailed analysis of the components in the climbing hydraulic system, according to the actual structure of the crane and possible fault conditions, it is possible to find out the reason of lifting accident with the help of fault tree analysis method, and form up the fault tree diagram; Finally, based on Monte-Carlo method, a reliability simulation diagram is set up, relative curve and index can be obtained, which indicated the weak point of the system, so we could conclude with an improving suggestion. According to the result of analysis, the hydraulic system satisfied engineering requirement, reliability can be further improved by purifying the hydraulic oil of the system, using explosion cut-off valve and increasing the reliability of critical components.This paper combines reliability simulation of climbing system with actual engineering project, its result proves that the method is feasible, according to the simulation data, we offer some helpful measures for improvement, and the improved system has an obvious and plausible enhancement compared with original one. This paper offers a reference for the maintenance and optimization of similar lifting hydraulic system, which has particular value in engineering application.