Research On The Giant Marine Dredging Grab Excavating Resistance And Simulation Experiment

During the"Twelfth five-year"period,our country has started?The National 863 High Technology Plan of Marine Areas?project.The project has proposed a strategic development demand to accelerate the pace of the south China sea oil and gas resources extraction.However,the scope of the south China sea is huge and far away distance.In order to realize the large-scale oil mining of the south China sea,large amounts of sea base must be built there.The construction of sea base requires a lot of building materials,transport them from the land is obviously impossible.So our country needs a batch of high efficiency large grab dredger to construct the offshore platform.But the domestic research on the technical theory of large grab dredger is very limited.For large dredging grab,the related technology development is in a blank.So our country needs to study the giant sea dredging grab which has greater volume and independent intellectual property rights.This topic based on the study of giant sea dredging grab,Set up an independent stress analysis system which is suitable for the giant grab's working conditions.Accomplish the structure optimization design and the discrete element simulation study on the mining process.The main research contents and results are the following several aspects:(1)We put forward the research purpose and meaning of this article,and the necessity of further research are given.On the basis of the literature,we fine introduces the research achievements of dredging grab excavating resistance and put forward the necessity of using discrete element simulation software to do the simulation experiments of the grab.(2)Based on the dredging rock and soil classification standard,we summarized all kinds of dredging rock and soil's physical and mechanical properties.Then in view of the giant sea dredging grab's special working environment,geological composition and characteristics of the nansha islands are analyzed,Finally we summarized the engineering properties of two kinds of typical material parameters.(3)Based on the giant sea dredging grab's special working environment,we determined its decorate form.Combining the theory of classical mechanics theory,the retaining wall and medium mechanics theory,deduced the calculation formula of the digging resistance,determine its point and direction,and given the expression of its arm,build the mechanics model of the digging process and the dynamic torque balance equation.(4)On the analysis of the digging process,we form the grab's mechanism optimization design model,with the aid of computer programming software we completed the 136 m~3 hydraulic dredging grab's key size optimization calculation,obtained the optimal combination of design parameters.Combined with the optimization results and design experience we determined the structure size of the grab bucket.Finally we take the136 m~3 hydraulic dredging grab mining reef sand both on land and underwater as an example,calculated all the resistance in the process of mining and the value of the grab bucket hydraulic cylinder thrust.(5)By using the discrete element method simulation software EDEM,We grabbed the mining process simulation experiment research,Won the digging force of the grab's components under several different initial insertion depth.Analyzed the law of resistance during the grab mining process,and verify the reliability of the theoretical calculation method.Provide a basis for the design and calculation of the grab bucket.