In this paper, the study of behavior characteristic of L-type flange bolt connection was performed. The L-type flange bolt connection is a method that upper and lower flanges with L-type ring section are connected by bolts. It is a connection mainly used in the domestic offshore wind structure. In the case of the wind turbine structure, the connection is one of the important structural components since an imperfection can cause a collapse of the entire structure system. Therefore, understanding the behavior characteristic of the L-type flange bolt connection is necessary. In this study, the response of the connection to the external force was simulated by FE analysis. And then the variation of the bolt tension and the L-type flange stress were analyzed to understand the behavior characteristic of the connection. Here, the FE model was idealized by a single L-type bolt flange. Also, the bolt-load function models proposed by Petersen, Schmidt/Neuper and VDI-2230, theoretically expressing a relation between bolt tension and external force, were compared to evaluate the suitability of FE analysis and analyze the significant behavior characteristics of the connection. Furthermore.
In order to analyze the shape of the L-type flange bolt joint dimension change on the behavior of the bolt-external force curve, the inner and outer lengths of the flange, the wall thickness, and the flange thickness were changed. By analyzing the relationship between the specification change and the bolt-external force curve, a correlation equation was proposed to estimate the external force when the bolt yields.
In addition, the tensile test of the L-type flange bolt joint was conducted to analyze the actual behavior, and the FE model was verified appropriate by comparing the behavior characteristics of the FE analysis.