DNV DNVGL-CG-0038 PDF

This class guideline consists of the procedure and the basic equations for verification of the load carrying capacity for shafts. It is an S-N based methodology for fatigue life assessment mainly based on the DIN 743 Part 1 to 3: 2000-04 Tragfähigkeits-berechnung von Wellen und Achsen and VDEH 1983 Bericht Nr. ABF 11 Berechnung von Wöhlerlinien für Bauteile aus Stahl, Stahlguss und Grauguss Synthetische Wöhlerlinien.

However, it is “adapted and simplified” to fit typical shaft designs in marine applications, such as marine propulsion and auxiliaries on board ships and mobile offshore units.

Examples of introduced simplifications are that axial stresses are considered negligible for marine shafting systems as they are dominated by torsional- and bending stresses and direct use of mechanical strength from representative testing.

Even though such shafts are exposed to a wide spectrum of loads, just a few of the dominating load cases need to be considered instead of applying e.g. Miner’s & Palmgrens’s cumulative approach. These typical few load cases are described in [2] and illustrated in Figure 1.

The permissible stresses in the different shafts depend on the safety factors as required by the respective rule sections.

A recipe for how to assess the safety of surface hardened or peened shafts is given in this class guideline.