- Title
- Application of the third medium contact method in geomechanics
- Creator
- Khishvand, Mohammad
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2018
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- The finite element method plays an important role in solving a wide range of geotechnical problems, particularly those involving the interaction between structural elements and geomaterials. These are often referred to as soil-structure interaction problems. Closed-form solutions based on the theories of elasticity and plasticity have been developed for structural foundations, layered soil systems, earth-retaining structures and tunnels. On the other hand, numerical algorithms in contact mechanics and computational geomechanics have been developed during the past few decades, facilitating solutions to many geotechnical problems. However, traditional approaches in contact mechanics require complicated search algorithms to detect nodes at the interface between the contacting bodies. More recently, a new contact scheme, the third medium contact method, based on a space filling mesh, has been developed in solid mechanics. This approach embeds the contacting bodies in a medium, whose properties are chosen to satisfy the contact constraints. The objective of this study is the further development and application of the recently developed computational contact algorithm for the analysis of geotechnical problems involving finite deformation and changing boundary conditions. The procedure involves new finite element (FE) algorithms that were formulated and implemented into SNAC-a bespoke finite element code developed by the geomechanics group at the University of Newcastle, Australia. The ability and accuracy of this method in predicting displacements, as well as the contact forces, is validated by solving selected numerical examples. The potential merits of this method for analysing geotechnical problems by the finite element method are also addressed and discussed. The analysis of the deformation of a solid soil phase coupled with the pressure of a pore fluid phase is a sophisticated problem in geomechanics. This problem becomes even more complex when the boundary conditions and boundary surfaces change during the analysis. In this study, the recently developed third medium contact method is further extended for analysing contact problems in geotechnical engineering in which the material behaviour is nonlinear, the soil may be subjected to large deformations, and the soil medium includes a solid phase as well as a liquid phase. By providing numerical solutions it is demonstrated that this method can overcome the drawbacks of the conventional techniques without significant additional effort. Non-smooth contact surfaces generated as a result of applying linear finite element meshes, have posed a noteworthy challenge in finite element analysis involving contact simulation. Another aim of this study is to investigate the capability of the third medium contact method when used with high-order elements in order to create a smooth contact boundary as well as to reduce the size of the numerical model. The capability of the proposed third medium contact method when combined with a high-order finite element discretisation is also investigated in this study.
- Subject
- finite element method; contact mechanics; third medium contact; large deformation; geomechanics; coupled analysis
- Identifier
- http://hdl.handle.net/1959.13/1383627
- Identifier
- uon:31969
- Rights
- Copyright 2018 Mohammad Khishvand
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 4 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 586 KB | Adobe Acrobat PDF | View Details Download |