- Title
- Theoretical and experimental analysis of the cutting process in sand
- Creator
- Kashizadeh, Elaheh
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2018
- Description
- Masters Research - Master of Philosophy (MPhil)
- Description
- Soil cutting processes are difficult to simulate using conventional approaches due to the occurrence of extremely large, predominantly plastic deformations. Pioneering methods in the study of soil cutting operations are based on the theory of critical state in order to analytically calculate resistance forces by using the limit analysis equilibrium technique. In these methods, often the stage of the ploughing process at which the predictions are applicable is not clear. Numerical techniques, such as the material point method and the discrete element method are, in principle, capable of reproducing the deformations observed in these evolutionary processes, but they are not without their drawbacks, the most significant being the large processing times required. This study presents a numerical technique for modelling the cutting processes in sands. The method rests on the assumption that deformations occur in the form of strong discontinuities, or shear bands, and considers the full process as a sequence of incipient collapse problems. Within an increment of deformation, the collapse mechanism furnishing the least resistance is used to update the deformed configuration and evaluate the force. The model incorporates the effects of softening within the shear bands, as well as the material avalanching observed as the slope of the free surface reaches the critical angle at which instabilities occur. Theoretical predictions are compared to experiments completed at the Centre for Offshore Systems at The University of Western Australia. A series of 1g tests were done to simulate the cutting process and to track the shear bands. The results have been analysed with PIV (Particle Image Velocimetry) in order to verify the numerical approach. The basic similarities and differences between the theoretical and experimental results are discussed, and potential future work in this area is described.
- Subject
- soil; cutting; ploughing; avalanching; softening
- Identifier
- http://hdl.handle.net/1959.13/1383972
- Identifier
- uon:32006
- Rights
- Copyright 2018 Elaheh Kashizadeh
- Language
- eng
- Full Text
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