Simulation Analysis Of Harmful Impact Vibration And Experimental Research Of Grab Dredger's Jib Structure

With the rapid development of Coastal and the Yangtze river deepwater Channel and marine engineering,the demand for Grab dredger in our country has grown up and there is demand for higher overall performance requirements for grab dredger.The jib structure acts as one of the important bearing part of Grab dredger,it is an important excavation equipment of Grab dredger,and its design quality and stable performance have great effect on the operating efficiency of the machine.As we know,Grab dredgers are operating on the sea,which makes the stress condition relatively complicated.So it is of great significance to analyze jib vibration caused by the harmful impact of jib in harsh environments,and it is helpful to understand its vibration characteristics,and avoid structure resonance,and improve its vibration performance.Considering the jib structure of 18 m~3 grab dredger as research focus,based on the theory of finite element method and dynamic analysis method,this research refers to virtual prototyping technology,and set up the grab dredger rigid coupled model.Dynamic simulation analysis of three different conditions such as full load lifting,rotating and unloading soil are performed,and truly reflect the vibration performance of jib structure in the process of operation.Through the stress testing on Grab dredger,this thesis compares the dynamic load stress testing curve with the virtual prototype simulation results.Main research contents of this thesis are as follows:(1)According to field research and theoretical analysis,the simulation conditions and load combinations are reasonably determined.On this basis,ANSYS software was used to make finite element structural statics analysis of grab dredger's jib structure,and analyze the relevant results to identify dangerous section of the position and the most dangerous condition to pave the way for the subsequent vibration simulation.(2)The modal analysis is carried out on jib structure,and the first 10 natural frequency,principal vibration mode and vibration mode are extracted.Then the results are analyzed to study the dynamic characteristics of jib structure,and establish the grab dredger dynamics model and research the mechanism and causes of vibration under different conditions.(3)Use SolidWorks software to establish rigid-body model and ANSYS software to establish jib structure soft body model,and import them to ADAMS,establish the coupled virtual prototype model of dredge.Establish the coupled model of dredge,simulate the lifting,rotating and grab unloading soil under the operation condition of the harmful vibration impact of jib structure through dynamics simulation analysis.(4)Through the stress testing on Dredger jib structure,check the strength and stability of the structure.Comparing rigid and soft coupling model simulation results with the testing data,judging the result of the dynamics simulation.This thesis completes statics calculation analysis of jib structure,and understands its mechanical characteristics and dangerous working conditions.Then jib structure's simulation is analyzed using impact vibration under different actions in the most dangerous working conditions.The results of the simulation are compared with actual data to establish correctness of simulation.The research work of this thesis has certain actual application value,and provides direction for the future dynamic design of dredger jib structure.