Finite element modeling of a suction caisson subject to monotonic tensile loading
| Author(s) | Green, Ryan | |
| Date Accessioned | 2020-01-03T14:20:39Z | |
| Date Available | 2020-01-03T14:20:39Z | |
| Publication Date | 2019 | |
| SWORD Update | 2019-08-07T16:02:40Z | |
| Abstract | Suction caissons are a proven method for securing floating oil and gas platforms in deep waters that have recently been garnering interest as a potentially more cost-effective, environmentally-friendly option to use in foundations for offshore wind turbines. However, due to complex interactions with saturated soils, the behavior of a suction caisson installed in dense sands under the unique loading regime of an offshore wind turbine is currently under vigorous numerical and experimental investigation. ☐ This thesis concentrates on using finite element analysis (FEA) to simulate the soil-structure interaction (SSI) of a single suction caisson installed in dense sands subjected to vertical pull-out at various speeds. Using a numerical formulation that accounts for the displacement of soil as well as the pore-fluid pressure between soil grains, a two-dimensional axisymmetric finite element simulation of a suction caisson under tension (i.e. pull-out) is constructed using the program ABAQUS 6.14. Special, low-stiffness elements were added to simulate seepage into the gap formed between the lid and the soil inside the caisson as it was pulled from the seafloor. The development of suction pressure within the interior and exterior of the caisson in response to pull-out at various rates is examined and presented for a range of void ratios and tensile loading speeds. The total resistance to pull-out and the response of the soil inside and outside the suction caisson at each velocity is also examined. ☐ As a basis for comparison, the observations of the numerical analysis are validated against the findings of an approximately 1:20 scale model test of a suction caisson undergoing tension loading at various rates. Overall, the results of the numerical modeling show strong agreement with experimental results for maximum pull-out resistance and suction pressure. Increased pull-out velocities resulted in higher total pull-out resistance and increased suction. The influence of initial void ratio of the soil and the Young’s modulus of the water elements is examined and shown to have an effect on the peak suction pressure achieved during extraction. ☐ Future work on the analysis presented in this thesis should focus on improving the modeling of interface friction to include fluid flow along the edges of the caisson in addition to implementing a three-field numerical formulation that accounts for pore fluid displacements and pressure, simultaneously. | en_US |
| Advisor | Madsen, John A. | |
| Degree | M.S. | |
| Department | University of Delaware, Department of Geological Sciences | |
| DOI | https://doi.org/10.58088/dsws-2197 | |
| Unique Identifier | 1134764077 | |
| URL | http://udspace.udel.edu/handle/19716/24917 | |
| Language | en | |
| Publisher | University of Delaware | en_US |
| URI | https://search.proquest.com/docview/2287049669?accountid=10457 | |
| Title | Finite element modeling of a suction caisson subject to monotonic tensile loading | en_US |
| Type | Thesis | en_US |