scope:

Although bellows have been used for many years in pressure vessels and piping, it is only relatively recently that detailed design by analysis rules have been provided in the ASME Codes, in Section VIII, Div 1 and in ASME B31.3. Similar rules are now being incorporated in the European Pressure Vessel Standard being prepared by CEN. Fatigue design of bellows has been via empirical design rules, entirely based on fatigue testing of bellows. While this has generally resulted in reliable performance of bellows with respect to fatigue, extension of fatigue curves constructed based on fatigue testing of bellows constructed of one material to bellows constructed with other materials is uncertain. As a result, qualification fatigue testing of bellows by the manufacturer is required by ASME B31.3 for any material other than austenitic stainless steel. Further, differences between the present reinforced and unreinforced bellows fatigue curves is not consistent with general understanding of material behavior. The present bulletin documents research performed to provide a better fundamental understanding of bellows fatigue performance which may lead to improved design