Reliability Study of the Hydraulically Expanded Tube-to-Tubesheet Joint

Abstract

A three-dimensional parametrized finite element model is established for the nonlinear analysis of the hydraulically expanded tube-to-tubesheet joint. Distribution of the residual contact pressure on the contact surface between the tube and the tubesheet is investigated. It is found that sealing circular bands exist on the contact surface which enhance the sealing of the joint since the residual contact pressures on the sealing circular bands are higher than on other positions. The sealing circular bands are located close to the two ends of the hole when it is not grooved, but they are located at the two brinks of the groove for a grooved hole and in the latter case, the residual contact pressures are even higher, reflecting that the joint with a grooved tube-sheet hole is more capable of sealing. Experiments and finite element calculations for the pull-out force of the joint are also performed for different expansion pressures and groove widths. Results show that with the increase of the groove width, the measured pull-out force increases significantly and becomes larger and larger than the calculated one, which is owing to the scratch on the contact surface between the tube and tubesheet.

The Influence of Modeling Methods on the Meshing when Solid Element Was Used in ANSYS - Taking the Design by Analysis of Dry Welding Experiment Module as an Example

“…At present, when the software ANSYS is used for the design of pressure vessels, it is suggested that the solid element should be used when the capability of computer and condition is appropriate, so as to simulate the actual situation much better and lead to a credible result [2]. Once the solid element is used in modeling, the meshing is an important link and it will influence the accuracy and scale of calculation directly [3]. There are lots of problems should be taken into consideration while meshing [4], such as 1) when solid element is used to simulate lamella structure, 4 layers of linear elements or 2 layers of quadratic elements should be existed in the direction of thickness; 2) For the model with no experience, basic mesh model and double mesh density model should be considered when checking the rationality of the size of mesh.…”