It is the most important thing to consider the fatigue strength of tubular connections at the design stage of offshore structures. Some design curves have been provided to estimate the fatigue strength of the tubular connections. One of the most popular curves is the X-curve in AWS Structural Welding Code. The ordinate of this curve is defined as the hotspot stress or strain. However, the definition of the term 'hotspot' is ambiguous, and a procedure to estimate the hotspot stress or strain seems not to be established even now. In this paper, the meaning of 'hotspot' was clearly defined as the location where the fatigue crack initates, and the value of strain at the hotspot was estimated by a simple procedure. Namely, the factors of stress concentration at a tubular connection were devided into two cmponents due to structural deformation and the existence of weld bead, and Stowell's equation was used to evaluate the plastic strain concentration factor.Subsequently, more than 100 pieces of fatigue test specimens were reanalyzed by this procedure and a fatigue design curve was obtained.(Wassmann)
A study of fatigue design procedure for tubular connections of offshore structures
Eine Untersuchung der Dauerfestigkeitsauslegung von Rohrleitungsverbindungen von Offshore-Konstruktionen
Journal of the Society of Naval Architects of Japan ; 148 ; 274-283
1980
10 Seiten, 10 Bilder, 4 Tabellen, 26 Quellen
Article (Journal)
English
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