| The conveyor& grab crane is the main equipment of the bulk cargo wharf. In addition to the poor working conditions and the heavy workload, the shocking from the materials when opening bucket discharge funnel can break the structure of the crane because of the severe vibration it brings to the crane. Therefore, It's urgent to research the dynamic issues happened in the conveyor& grab crane working process. Through the study of its dynamic characteristics, we can figure out ways to control them.This article takes the conveyor& grab crane as its study object. Based on theories of finite element method, mechanical vibration, structural dynamics, taking advantages of ANSYS software, the static and dynamic characteristics of this kind crane are deeply researched, mathematical modeling and numerical simulation are built. The main work includes the following aspects:(1) A structure model of the selected conveyor& grab crane is built on ANSYS11.0, which is finite element analysis software. And the model was statically analyzed.(2) The whole unloading process of the conveyor& grab crane is the working condition to calculate. Dynamic load variation laws in this working condition was found, dynamic load data and curve was carried out, and its dynamic model was established.(3) By analyzing the dynamic response of the structure in the ideal state (i.e. to grab and to funnel,materials don't have simultaneous effect) of every stage of material unloading process, the displacement response and speed response were given, and their response curves were drawn in MATLAB, helping to find out the factors which would impact the discharging and dynamic loading.(4) Displacement expressions of each unloading stage in actual working state were given out after a series of analysis, and they were expressed in MATLAB. By comparing their response curves under the ideal condition and the actual state, two factors were pointed out, and their influence to dynamic characteristics of the conveyor& grab crane were shown.(5) The model of the conveyor& grab crane was analyzed in ANSYS by using Block Lanczos method. Low vibration frequency and the corresponding main vibration model were given, and the reasons of vibration were analyzed.(6) Using FULL method to make transient dynamic analysis to the conveyor& grab crane, the displacement response value and the maximum stress value were reached in both ideal and actual working conditions. Showing these values in MATLAB, and then comparing with the results we got from ANSYS, we finally verify the correctness of the theory analysis conclusion. |
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