With the massive development and utilization of offshore wind energy, offshore wind turbine has become an important marine engineering structure. In the process of construction, due to the limitation of working environment and welding process, the welded parts of the pipe wall will appear structural dislocation, which will result in structural stress concentration, and resulting in great safety hidden danger. Based on the idea of multi-scale modeling, this paper adopts different modeling methods to simulate welding dislocation with plate element and solid element respectively. In this paper, the structural response is analyzed by numerical calculation, and the stress concentration factor under different modeling methods is obtained.On the basis of the above research, the structural response under different degrees of dislocation is calculated, and the stress concentration factor is compared with the standard value, which further improves the calculation and treatment method of the stress concentration factor in the code, and puts forward the correction formula of the stress concentration factor under the large amount of dislocation.
As a simple, safe and reliable basic structure, jacket is widely used in marine development. In the construction process, the connection between the pipe is usually in the form of welding(Yang J,2013), due to the limitation of working environment and welding technology, it is unavoidable to appear the welding dislocation of pipe wall. Under the action of alternating loads, such as wave, tide and current, the structural structure of ducted frame is in the sea for a long time. The stress concentration will occur at the local dislocation and fatigue will easily occur, damage the integrity of the whole structure(ARGYRIADIS K,2017; Han C,2013), bring great economic losses and even staff safety problems.
An Z (2010)analyzed the dislocation stress of welded structure in the complex structure of jacket. He used ANSYS to carry out finite element analysis of different points in the dislocation structure, and evaluated the applicability of common formulas. Wen Xiong et al(2019). used ABAQUS to establish different dislocation pipe pile models and analyzed the influence of dislocation quantity on the structural strength of pipe pile, providing reference for practical engineering applications. Lotsberg I(2009)verified the correctness of Lotsberg's formula under small dislocations, which was also adopted by DNV specification.
