Dynamic Interactions of a Pipe System With a Seafloor Miner for Deep-Ocean Hardrock Mining

目前的理论是基于结合一种新的概念，即连接到采矿机的垂直管道和在管道上施加外部（控制）力以控制管道采矿机运动。 整个管道采矿机系统的建模将水平管道销连接到长的、接近垂直的管道系统和自推进的海底采矿机。 沿管道的弹性接头沿着可有效地改变轴向以及弯曲特性。 为了向接头施加外部（控制）力以控制管道的横向运动，将通过有限元（FEM）以及组合（刚体）单元（RBE）对柔性接头进行建模。 比较两种方法的精度和优点。 销连接使整个系统趋于零特征值和刚性模态，而重量作为竖管的内轴力，进一步影响整个系统的特征值。 移位技术可以解决这个问题。 在节点处设置非线性轴向阻尼器，可以有效地减小节点的轴向应力，同时对节点的弯曲和扭转也有一定的影响。 采矿机的土壤（沉积物）阻力将通过DEM（离散单元）和FEM建模。 DEM建模将使用大量一般几何形状的离散颗粒。 土颗粒的初步模拟表明，DEM模拟是非常有前途的研究细观力学细节的土壤颗粒。 ***

9531182 Chung Present theory is based on incorporating a new concept of vertical pipe connecting to a miner and application of external (control) force on the pipe for the control of pipe- miner motions. Modeling of an entire pipe-miner system pin-joins a horizontal pipe to the long, near-vertical pipe system and to a self-propelling seafloor miner. The elastic joints along the pipe can be made effective in changing the axial, as well as, bending characteristics. To apply external (control) forces to the joints for the control of the lateral motion of the pipe, the flexible joints will be modeled by finite element (FEM), as well as combined (rigid body) element (RBE). The accuracy and advantages of the two methods will be compared. The pin joint leads the entire system to zero eigenvalue and rigid mode, and the weight, as the inner axial force of the vertical pipe, further influences the eigenvalues of the entire system. A shift technique will solve this problem. The proposed 3-D nonlinear coupled responses with nonlinear axial dampers installed at the joints will reduce the axial stress and also influence the bending and torsion, as well. Soil (sediment) resistance for the miner will be modeled by both DEM (discrete elements) and FEM. The DEM modeling will use a mass of discrete particles of general geometry. Preliminary modeling of soil particles indicates that DEM modeling is very promising to examine micromechanical details of the soil particles. ***