This paper describes a fracture and fatigue analysis performed on an NPS 12 x NPS 36 hot tap tee. The analysis considered a hot tap tee configuration consisting of a branch stub welded to the run pipe, with the opening reinforced with a split full-encirclement saddle. A structural analysis was performed using a three-dimensional elastic/plastic finite element analysis (FEA) model. The modelling consisted of two parts: an global model that was used to determine stress and strain in the overall assembly, and a sub-model focusing on the area of the branch-stub to run-pipe intersection to determine the fracture and fatigue driving forces. The location of fatigue concern is the toe of the stub to branch weld. The FEA sub-model incorporated a crack at this weld toe, and this model was used to derive an applied CTOD in response to a combined pressure, axial compressive force on the branch, and a dynamic inplane bending moment applied to the branch pipe. Applied CTOD at various moment loads was used to calculate an applied delta K Conventional delta K fatigue threshold considerations were used to determine a maximum applied in-plane moment to avoid fatigue crack growth. Descriptions of the overall FEA model and the sub-model are given.
Fracture and fatigue analysis of a hot tap tee
Bruch- und Ermüdungsanalyse eines Warmanzapf-T-Verbindungstückes
2000
13 Seiten, 10 Bilder, 13 Quellen
Conference paper
English
Emerald Group Publishing | 1960
|Fatigue and Fracture: Fatigue and Fracture of Ship Structure
British Library Conference Proceedings | 1997
|British Library Conference Proceedings | 1997
|Fatigue and fracture mechanics
NTRS | 1971
|