Optimization Of New-type Drag Anchors

In the ocean of China,there are a lot of oil and gas resources. And how to explore and exploit these resources is an important task for scientific and technological circles of China. Being a new-type mooring foundation used for deepwater engineering, which is embedded in seabed soils by dragging, the vertically loaded anchor (VLA), combined with the taut-wire mooring system, has predominant advantages in deepwater applications compared with other types of anchors. Accurate predictions for the trajectory of fluke during the installation process is the key to studying VLA.Factors affecting the shape of the anchor a brief introduction, analysis of the anchor plate structure of the main functions of each detail. For the shape optimization has laid a theoretical foundation.Based on explicit dynamic analysis software LS-DYNA, this paper introduces dynamic simulation analysis of sinking and installation process. These mainly achievements are in the following aspects:This paper presents thorough and simplified analysis of sinking and installation of VLA, including the use of perfectly plastic soil constitutive model, soil ALE algorithm and application of ansys / ls-dyna in setting up a dynamic model considering the legal effect of the anti-hanging chain to VLA .Field experiment provides the basis of established model of fluke and it also validates the results of dynamic VLA model.Based on a dynamic model considering the legal effect of the anti-catenary chain to VLA . installation process,this paper mainly discuss several factors that will affect the embedding trajectory and ultimate embedding depth. The laws of the trajectories of installation,ultimate embedding depth and dragging force are analyzed by changing the fluke-shank angle, the contrivable anchor tibial length and the shape of the fluke.Based on the results of model tests, the design principles and methods on the shape optimization are proposed, meanwhile, a new anchor is designed. And comparing the results between the new anchor and the ordinary one.