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F. Rauscher:
"Fatigue of non-welded pressure vessels made of high strength steel";
International Journal of Pressure Vessels and Piping, 80 (2003), 3; S. 197 - 204.

When using high strength steels for pressure vessels, cyclic fatigue requirements may become decisive for the design. Within a European research project,1) two typical non-welded types of vessels-gas cylinders as used for gas transportation and hydraulic accumulators with screwed in ends-were investigated. The results of the fatigue analyses and of the testing of these vessels are described here.
Special attention is drawn to the evaluation of the stresses in the threads used for threaded in flat ends and rings, because the usual formulae for bolted connections cannot be used. In the case of sharp notches and of threads, the experiments showed that the fatigue calculation gave conservative results.
The unexpected failure of the gas cylinders in the cylindrical part and at the onset of the end showed that the fatigue analyses according to prEN13445-3 clause 18[1] is non-conservative for these surfaces without mechanical preparation, and need special consideration. Based on the investigations, a stress concentration factor for small fabrication notches and a new surface finish factor is proposed.
Keywords: Pressure vessels; Fatigue; High strength steel; Threads; Gas cylinders; Hydraulic accumulators
1) Research project 'Advanced Design Methodologies to Exploit High Strength Steels for Pressure Equipment Manufacture', funded by the European Community, EC DG-Enterprise under the call DGIII/98/16: Institut de Soudure (FR); Ecole des Mines de Douai/Armines (FR); Technische Universität Wien, Institut für Apparate- und Anlagenbau (AT); Gu Baylac (FR).