The Study Of Jack-up Structure Computing Model

As a typical and complex ocean engineering structure, jack-up is always working in the tough environment. So when the overall strength of the structure is analyzed, reasonable mechanical model, which can simulate the geometry of the actual structure, the interaction of adjacent structure, the support status, the size and distribution of loads and the environmental conditions, is very important.In this paper, three different models of one jack-up, including space frame model, thin-walled space model and large-scale three-dimensional simulation model are established with ANSYS, and then stress and displacement static of every model in survival condition are computed. Based on the results of comparison and analysis, it can be concluded that: because of different simplification and simulation of the structures, different links between the structures, both the largest displacement and maximum stress of the pile legs are gradually increasing with three models becoming more and more true, however, the positions of maximum stress are different; And the features and application of every model can be drawn from the results of the hull.For the boundary problem of the bottom of pile legs, according to China Classification Society, Rules for the Construction and Classification of Mobile Offshore (2005), two methods, the establishment of constraint equations and rigid plate, are suggested to solve the problem. Through analysis and comparison, it is proved that the above two methods are feasible.Taking into account the larger lateral displacement of pile legs, the model is analyzed by both ANSYS large displacement static analysis and additional moment method. And it is concluded that the result using ANSYS is about 5% more than the other.This paper has some reference value and provides guides for the overall strength analysis of jack-up in the selection of model, the simplification and simulation of the structures, the connections between structures and the boundary of pile legs.