Investigation For Limit Load Of Oblique Nozzle With Large Opening Rate

The oblique nozzle is an indispensable and important structure in the pressure vessel. Reasonable design and safety assessment are essential to ensure the safe operation of the vessel. Plastic failure is one of the main failure modes due to the extensive use of high-strength steel. In recent years, a large number of experimental and modeling studies have been taken by domestic and international scholars, but mostly limited to a small rate of opening in orthogonal intersecting nozzle, and little to large opening rate with a tilt angle oblique nozzle. Therefore, it is of engineering significance to research the limit load for pressure vessel with a large opening rate oblique nozzle.The limit load analysis of oblique nozzle with a large opening rate is calculated by the universal finite element software—ANSYS. The main contents are as follows:Compare different criteria by how to determine the limit load, and according to the latest requirements of ASME, use " Stop Calculation " to determine the limit load of the structure, and then verify the limit load accuracy. Proving that the " Stop Calculation " to solve the structure limit load is feasible with high accuracy and meets project requirements.Use the " Stop Calculation " to solve the limit load of oblique nozzle with a large opening rate in the pressure vessel, and study the plastic failure process of oblique nozzle, investigate the stress、deformation and the location of plastic yield in the whole failure process. The plastic region first appeared in acute angle side. In the plastic yield, obvious plastic deformation and the radial bulging occurred in mitered pipes, as well as cylinder radial bulging deformation in the pipe.Investigate the affects for the limit load of oblique nozzle by various parameters. The tilt angle θ, the thickness ratio t/T and the opening ratio d/D, and summarize the result so as to use easily in engineering application. Parameter variations have a significant impact on the limit load of oblique nozzle. As the tilt angle θ or the thickness ratio t/T increases the limit load increases. Conversely, the opening ratio d/D increases, the limit load reduced.