Analysis Of The Causes Of Trolley Track Fracture On Bridge-type Grab Ship Unloader

With the rapid growth of the domestic import and export trade volume, port number and cargo throughput is constantly increasing, the use of port shore crane lifting handling machinery is also more and more. Due to the strong adaptability to ship material and the high operation efficiency,these advantage help the bridge-type grab ship unloader widely used in domestic and foreign big bulk cargo port.The trolley track is an important part of bridge-type grab ship unloader, is also the basis to ensure the normal operation of the trolley. With the increasing amount of port operation, the frequency of trolley track malfunction is more and more higher,in which the track fracture failure is the greatest harm. Not only make the trolley traveling mechanism dramatic shock at run time,which will cause metal structure of trolley traveling mechanism crack and the electrical wiring loose fault, without the timely detection of treatment,it will cause a major engine damage and casualties. After the fracture failure of trolley track happened, to take welding or replacement approach to the fracture of track, not only can not fundamentally solve the problem of orbital fracture failure, but will also cause enormous waste to the enterprise. Therefore, to research the causes of trolley track fracture on bridge-type grab ship unloader has the great practical significance.This thesis through analysis of the causes of trolley track fracture on 2250t/h bridge-type grab ship unloader in a port,find out the reasons of track fracture,and put forward the prevention measures,which can provide basis and reference for improving the service life and reliability of the trolley track.The main contents of this thesis are as follows:(1) This thesis introduces basic theory of fracture mechanics and fatigue analysis, which can provide a theoretical basis for the static and fatigue analysis of trolley tracks.(2) The static analysis of the trolley track by using the finite element analysis software, and combined with the basic theory of fracture mechanics, find out the reasons of track fracture from the perspective of the impact of static stress size.(3) Establish a solid model of track surface with micro cracks,do the static analysis of the trolley track,and combined with the expression of the stress intensity factor, find out the reasons of track fracture from the perspective of the impact of stress intensity factor size.(4) Considering the impact of the wheels in contact with the track plastic deformation factors,do contact analysis of trolley track and wheel by using the contact mechanics knowledge,and combined with the fatigue cumulative damage theory, find out the reasons of track fracture.(5) According to S-N stress fatigue life curve of the track,do fatigue analysis of the trolley track.Obtain the fatigue life and dangerous area of the trolley track,and analyze the impact of the different support conditions on the trolley track life.Finally,summarize the causes of trolley track fracture,and put forward the reasonable and effective prevention measures to avoid the recurrence of similar failures,which can provide a theoretical basis for enterprises to improve the level of safety in production.