Abstract
Pressure vessels can be subjected to various external local forces and moments acting in combination with main internal pressure. As a result of the stress system set up, and in the presence of attachment welds, surface cracks can occur on the interior and exterior walls. If these cracks cannot be detected at an early stage, there is a real potential for the vessel to rupture with obvious dangerous consequences. The behavior of fractured or geometric discontinuity structures can be investigated with linear elastic fracture mechanics (LEFM) parameters. The stress intensity factor (SIF) is the leading one, and with correct calculations, it can produce the stress intensity in the crack tip region. In cylinder-cylinder intersections subject to local loads, the maximum stress distribution occurs in and around these opening areas and failure in the system usually occurs in this region.
Using this approach, the present study develops threedimensional mixed mode stress intensity factor solutions on for external cracks on nozzle joints in cylindrical pressure vessels nozzle junctions for a variety of geometrical configurations. This was undertaken using a finite element approach and employing a bespoke software tool and solver, FCPAS-Fracture and Crack Propagation Analysis System-to create the finite element mesh and propagation characteristics. From this, a parameter study examining the influence of the crack shape, size and position was carried out with a fixed pressure vessel nozzle cylinder intersection geometry configuration and the appropriate stress intensity factors identified and reported. The FCPAS tool is shown to be an effective approach to modelling and characterizing cracks in pressure vessel nozzles.
Original language | English |
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Title of host publication | Proceedings of ASME 2021 Pressure Vessels & Piping Conference |
Subtitle of host publication | Computer Technology and Bolted Joints; Design and Analysis |
Place of Publication | New York |
Publisher | American Society of Mechanical Engineers |
Number of pages | 10 |
ISBN (Electronic) | 9780791885321 |
DOIs | |
Publication status | Published - 18 Oct 2021 |
Event | ASME 2021 Pressure Vessels and Piping Conference, PVP 2021 - Virtual, Online Duration: 13 Jul 2021 → 15 Jul 2021 |
Publication series
Name | American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP |
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Volume | 2 |
ISSN (Print) | 0277-027X |
Conference
Conference | ASME 2021 Pressure Vessels and Piping Conference, PVP 2021 |
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City | Virtual, Online |
Period | 13/07/21 → 15/07/21 |
Keywords
- crack
- finite element analysis
- fracture
- local loads
- nozzle intersection
- pressure vessel
- stress intensity factor