Research On Initial Penetration Of Torpedo Anchor Into Seabed Soil

With the exploration for oil and gas into deepwater or ultra deepwater, the cost of the deepwater mooring foundation is increasing higher. It is of necessity to make the research and development of deepwater anchors with low cost and high holding capacities. Torpedo Anchors have the advantages of low cost, simplified installation and high holding capacity. So Torpedo Anchors appear to be the new most promising deepwater mooring anchors.The paper aims to present the curve between penetrations and different anchor velocities by using a MATLAB program with Runge-Kutta method onto the ordinary differential equations of Torpedo Anchor's motion, and presents further research on the initial penetration depth of Torpedo Anchor into seabed soil influenced by various parameters such as the characters of seabed, the free-fall heights (different impact velocities) and anchor weights. And rules can be obtained from the research. In addition, the brief analysis on directional stability of Torpedo Anchor is presented with the basic theory of hydrodynamics.Finally, another method is the three-dimensional numerical simulation about the installation process of Torpedo Anchor by a nonlinear dynamic analysis program ANSYS/LS-DYNA. During the process of Torpedo Anchor penetrating into water and seabed, the non-reflection boundary and elastic-plastic material of soil are taken to obtain the initial penetration of Torpedo Anchor into seabed and the curve of velocity-time and displacement-time history of Torpedo Anchor. By comparison, the analytical and numerical solutions are in good agreement.