Establishment of an Improved Dynamic Model of the Total Deep Ocean Mining System and Its Integrated Operation Simulation

摘要

An Improved dynamic model of the total deep ocean mining system is established. The pipeline subsystem is built as a 3D discrete element model, which is divided into 3D rigid elements linked by flexible connectors. The flexible connector without mass is represented by 6 spring-damper elements. The external hydrodynamic forces from the longitudinal and lateral directions are both considered and modeled based on the Morisson formula and applied to the mass center of each discrete rigid element. The seafloor tracked miner is built as a simplified 3D single-body model with 6 degrees of freedom. While the trackterrain interaction is modeled by partitioning the track-terrain interface into a certain number of mesh elements with three mutually perpendicular forces, including the normal force, the longitudinal and the lateral shear forces, acting on the center point of each mesh element. With consideration of the operational safety and collection efficiency, two new moving paths for the miner on the seafloor are proposed, which can be simulated with the newly established single-body dynamic model of the miner. Integrating the discrete element model of the pipeline and the single-body model of the miner, a new improved dynamic model of the total deep ocean mining system is finally formed. Two new mining operation process modes of the total mining system, which combine of the active straight-line and turning motions of the miner and the ship, and of the passive towed motions of the pipeline, are proposed and simulated with the new improved 3D dynamic model. Some critical simulation results are obtained, such as the motion trajectory of each key subsystem during the operation process and the velocities of the buoyancy module, which in a way can provide specific guidance and useful reference for the practical deep ocean mining system analysis, operation and control.