Study On Parameterized Finite Element Modeling For Tubular Joints In Offshore Platforms Structure

Tube structure is widely used in offshore platforms, and tubular joints play an important role in structures connection and loads transfer. Because of those tubular joints subjected to long-term cyclic loads. Crack and fatigue failure almost appear in those parts. Therefore, in the structure design and strength analysis of offshore platforms, tubular joints design is the key point. In the practical engineering structure, there are various types of tubular joint. It is a great workload and inefficiency to do the finite element modeling.Basic tubular joint types includes the planar tubular joints(T-Joints、Y-Joints、X-Joints、 K-Joints) and the multiplanar tubular joints(KK-Joints、TT-Joints、XX-Joints). A set of specific parameters can be summed up for each type of tubular joints. In this paper, the parametric Finite Element modeling preprocessor program is developed with VB.NET, useing ANSYS as modeling tool. The ANSYS command stream will be generated automatically, and then read by ANSYS, which realizes parameterized modeling for tubular joints. A lot of repetitive manual workload will be avoided and the design efficiency will be improved.The research content of paper could be divided into five parts as follows:(1) The analysis of tubular joint, which includes the study of joint types and joint stress.(2) Research on the meshing principles and methods. Using the method of meshing separately, and study more on the mapping meshing of the key part. Realizes the regular transition from sparsity to density.(3) Study on the effect of geometric elements on meshing tubular joints. It is found that the thickness could be judging the conditions of meshing density.It can be considered that the meshing density met the requirements when the size of elements around weld seam is approximately equal to the thickness.(4) Shell elements are widely used in modeling tubular joints by ANSYS. Considering the limitations of shell elements. The analysis results using shell and solid elements respectively are contrasted, providing advices to select element type when modeling tubular joints.(5) Develop Finite Element modeling preprocessor program by VB.NET. Realize parameterized modeling for various types of tubular joint.