Compiling Method And Application Of Load Spectrum Of Bridge Type Grab Ship Unloader

The port is the ocean transport and land transport hub,and bridge type grab ship unloader is an important cargo transfer tool.Its structure is the before and after horizontal girder crane hanging on the cross beam which is supported by sea side column.in the port.The ship unloader has larger stretch distance,which allows it to adapt to a variety of different types of ship and transport the bulk material from the bulk cargo ship to land.With the vigorous development of maritime transportation,bulk cargo transport ship becomes larger,making higher requirements on grab bridge ship unloader,so that high speed and heavy load has become its main force characteristics and fatigue problems have become more and more obvious.It often causes serious mechanical accident once the fatigue failure occurs,for the ship unloader's high tonnage and large span.Therefore,it is urgent to study the fatigue damage of bridge grab unloader by using scientific analysis and calculation method,in order to provide reasonable suggestions for on-spot managers to prevent the occurrence of fatigue failure.This dissertation will carry out a research on the fatigue damage of the ship unloader's metal structure.The main contents include the following aspects:(1)Present the research status of load spectrum and fatigue analysis at home and abroad by literature review.The relationship between load spectrum and fatigue is explained in detail.(2)At present,there are few researches on the compiling method of the load spectrum of the bridge type grab ship unloader.The compiling method of existing load spectrum is rather rough.In view of this situation,the paper studies the theory of load spectrum.Put forward a method to create regions of the key parameters of load spectrum by using cluster analysis for the shortage of the existing load spectrum compilation method.And summarize the theoretical knowledge of load spectrum.Last,give the steps of compiling load spectrum in detail.The above work lays a theoretical foundation for the subsequent work.(3)Compile the load spectrum of a specific in-service bridge type grab ship unloader,according to the load data.Give the whole load spectrum of the research object.(4)Briefly introduce the characteristics and forms of fatigue damage and fatigue analysis methods based on different theory.Considering the characteristics of ship unloader itself,chose British BS5400 fatigue standard that is based on nominal stress method and linear cumulative damage theory.And then,carry out fatigue analysis for the ship unloader,referring the previously load profile,to obtain the calculation of residual fatigue life of the ship unloader.