Dynamic Research On The Process Of Lowering The Lifting Pipe In Deep Sea Mining

In recent years,with the reduction of terrestrial mineral resources and the large demand for rare mineral resources in the new energy battery industry,the exploration and development of submarine minerals has attracted the attention of many governments and companies.As an important part of the deep-sea mining system,the ore lifting pipe is subjected to the combined action of the mining ship’s heave motion and wave current during the lowering and installation process,which makes the ore lifting pipe produce large longitudinal vibration,lateral displacement and lateral vibration.It will not only affect the life of the lifting pipe,but also affect the lowering and installation of the lifting pipe,and cause the failure of the lowering in serious cases.Therefore,it is necessary to carry out a dynamic study on the lowering process of the hoisting pipe.This paper studies the dynamics of the mining pipe on the basis of the mining system combined with the mining machine and the pipeline conveying mining system,and the way that the mining machine and the relay station are distributed separately.Firstly,the ore-lifting pipeline system is simplified,and the longitudinal vibration mechanics model and longitudinal vibration equation of the ore-lifting pipe under the heave motion of the mining ship are established.The variation law of longitudinal vibration displacement and axial stress and the influence of pump group position distribution on the longitudinal mechanical response of mining pipe.Secondly,establish the lateral vibration mechanical model and lateral vibration equation of the lifting pipe under the combined action of waves and currents,use the difference quotient method to obtain the lateral displacement,shear force and bending moment of the lifting pipe,and obtain the change of the lateral vibration displacement of the lifting pipe The influence of the law and the position distribution of the pump set on the lateral mechanical response of the mining pipe.On the basis of the previous analysis,the coupled dynamics simulation model of the mining vessel-lifting pipe system is established in the Orca Flex software,and the dynamic analysis of the lowering process of the lifting pipe is carried out.Firstly,the variation of the mechanical response of the lifting pipe along the pipe length and the variation trend of the mechanical response during the whole lowering process are analyzed at different water depths.Secondly,a dynamic analysis is carried out to study the changes of the top rotation angle,the maximum longitudinal vibration displacement and the lateral vibration displacement of the bottom end of the lifting pipe at different water depths.Then,the parameter sensitivity analysis and orthogonal test analysis are carried out to obtain the influence rule and influence degree of different parameters on the mine-lifting pipe.Finally,according to the main influencing factors of the decentralization process,the decentralization operation window of the lifting pipe at different quality relay stations is obtained,which has positive significance for the decentralization and installation of the deep sea mining system.