Generation of load series for fatigue testing of DY tubular joints

Abstract

In this work, different stress time series generated using different methods are produced. The objective is to generate a load time series which would be fast to cause a failure in the model structure, while maintaining the statistical values of the data given by the partner company Ramboll. This data is, among other, stress time series for five loading conditions for a D-K joint. As the model structure is a D-Y-joint a FE model was created to create an influence matrix. This influence matrix would transform the stresses of the D-K joint into the D-Y-joint, while reduced the degree of freedom from 6 to 2. In the FE model, 12 hotspot were modeled, 6 placed at the chord and 6 at the brace. In order to choose one hotspot, an optimization for the minimal error was done, to see which point could be better simulated with the brace forces. The best point was point 4 corresponding to the hotspot from the full-scale structure HP 130.205.