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Northeast Forestry University (2005)

A Study on Passability of Paving Square Straw Mechanism for Preventing Sand Flow

赵志国;

Titre : A Study on Passability of Paving Square Straw Mechanism for Preventing Sand Flow

Auteur : 赵志国;

Grade : Master’s Theses 2005

Université : Northeast Forestry University

Résumé
As the national "863" plan project "Paving square straw Robot for preventing sand flow" is meaningful for us to effectively combat land sandy desertification. Passing performance of vehicle, which will influence the straw paving and the efficiency of the mechanism, is a key problem in vehicle engineering .Therefore, Study on it is one of parts in this project.Several methods about studying walking mechanisms-ground interaction were summarized and inducted in this paper. Referencing existing methods and achievements, the writer offers the best towing tractor and walking mechanisms for the paving straw robot.Regard sand-soil of the desert area of Ulan of Dengkou county of the Inner Mongol province as the research object, the writer carries on experimental study to physical property and mechanics nature of it. According to the basic theories of computational mechanics, two dimensional finite element model of the tire-sand interaction is set up through FEA and the numerical simulation to the drive wheel and sand-soil interaction is also carried on through large-scale finite element analysis software ANSYS. Changes under the function of the tire such as sand-soil deformation, stress and displacement, etc. are drawn. Summed up each nodal horizontal stress of the area drive wheel and sand-soil exposed to, thus the driving force of the drive wheel is asked out.Theory predicted value of friction between the tire and sand-soil is calculated out with semi-empirical method. At the same time bulldozing resistance and the influence on driving resistance while the wheels passing repeatedly are considered ; The resistance is computed when horizontal insert knife pushes away sand through Rankine’s earth pressure theory is derived. And the other one is computed while the vertical gyro wheel pressing straw is also derived from pressure-sinkage characteristics model put forward by Bekker.Pressure-sinkage experiment is done in desert area of Ulan of Dengkou county of the Inner Mongol province and shear characteristics experiment is done in the laboratory. Through test data, driving force, resistance and drawing parameters are calculated in theory. And according to drive force graph under the different slip rate, the actual one is worked out. Finally, whether this tractor accords with the passing demand in this area is justified

Mots clés : vehicle; desert; passability; tire; finite element analysis;

Présentation (CNKI)

Page publiée le 11 octobre 2017