Unit Integration Method Solution and Experimental Research on Mechanism Characteristics for Flat Digging of Grab Dredgers

Abstract

In the process of grab dredger dredging, how to ensure the accuracy of flat digging is a key technical question. The accuracy of flat digging is related to the force of grab digging. However, there are limitations in the traditional method of studying the force of grab digging. In this study, based on the Rankine theory, the unit integration method is proposed to calculate the force process of grab excavation. This method determines the shape and position of the failure surface under the action of active pressure FB and passive pressure FE and further obtains a functional expression for the relation between digging force and digging parameters. Through the simulation of flat digging force using the discrete element method (DEM), we obtained results consistent with the calculation results of the unit integration method. In addition, this study sought to control the movement distance of the closing wires and the hoist wires through the equation of motion, to carry out the precision calculations of theoretical data, and experimental research into grab flat digging. By comparing theoretical data and test data, the following conclusion was drawn: the deviation of the theoretical flat digging precision from the test data falls within the allowable range, at 3.15%. This study provides technical support for the flat digging process of the grab dredger.