Extended numerical manifold method for engineering failure analysis

In this thesis, the numerical manifold method (NMM) has been extended for engineering failure analysis. The NMM has been coupled with the fracture mechanics to simulate the complex cracks and their growth. A new concept ‘singular physical cover’ is introduced. Asymptotic crack tip functions extracte...

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Main Author: An, Xinmei
Other Authors: Ma Guowei
Format: Theses and Dissertations
Language:English
Published: 2010
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Online Access:https://hdl.handle.net/10356/42227
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-422272023-03-03T19:06:27Z Extended numerical manifold method for engineering failure analysis An, Xinmei Ma Guowei School of Civil and Environmental Engineering NTU-MINDEF Protective Technology Research Centre DRNTU::Engineering::Civil engineering::Structures and design In this thesis, the numerical manifold method (NMM) has been extended for engineering failure analysis. The NMM has been coupled with the fracture mechanics to simulate the complex cracks and their growth. A new concept ‘singular physical cover’ is introduced. Asymptotic crack tip functions extracted from the analytical solution are chosen as the local approximation spaces of the singular physical covers. The domain form of the interaction integral and the maximum circumferential stress criterion are employed to evaluate the stress intensity factors at the crack tips and to predict the crack growth direction, respectively. Several typical crack problems are simulated. The numerical results show that the extended NMM can resolve the stress singularities around the crack tips well, and it is efficient and robust for complex crack problems. In addition, the extended NMM is obviously superior to the conventional finite element method (CFEM) and its various modifications, such as the extended finite element method (XFEM), the generalized finite element method (GFEM), etc. The NMM has also been extended to account for the practical rock failure process. The Mohr-Coulomb criterion with a tensile cutoff is employed to predict the crack initiation and propagation. A cover-division strategy is adopted to fulfill the crack initiation and propagation. The cover-division strategy can avoid the mesh dependency to some extent because of the non-local nature of the stress. Algorithms are implemented to treat the manifold elements, the physical covers and the loops during the fracturing process. The developed program has been applied to simulate the progressive failure of rock slopes with non-persistent joints. Numerical results indicate that it is able to capture the fracturing in intact rock bridge and finally allow the kinematic release. The developed program has also been applied to investigate the potential failure mechanisms of footwall slopes in surface coal mining. Doctor of Philosophy (CEE) 2010-10-04T04:12:21Z 2010-10-04T04:12:21Z 2010 2010 Thesis An, X. (2010). Extended numerical manifold method for engineering failure analysis. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/42227 10.32657/10356/42227 en 308 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Civil engineering::Structures and design
spellingShingle DRNTU::Engineering::Civil engineering::Structures and design
An, Xinmei
Extended numerical manifold method for engineering failure analysis
description In this thesis, the numerical manifold method (NMM) has been extended for engineering failure analysis. The NMM has been coupled with the fracture mechanics to simulate the complex cracks and their growth. A new concept ‘singular physical cover’ is introduced. Asymptotic crack tip functions extracted from the analytical solution are chosen as the local approximation spaces of the singular physical covers. The domain form of the interaction integral and the maximum circumferential stress criterion are employed to evaluate the stress intensity factors at the crack tips and to predict the crack growth direction, respectively. Several typical crack problems are simulated. The numerical results show that the extended NMM can resolve the stress singularities around the crack tips well, and it is efficient and robust for complex crack problems. In addition, the extended NMM is obviously superior to the conventional finite element method (CFEM) and its various modifications, such as the extended finite element method (XFEM), the generalized finite element method (GFEM), etc. The NMM has also been extended to account for the practical rock failure process. The Mohr-Coulomb criterion with a tensile cutoff is employed to predict the crack initiation and propagation. A cover-division strategy is adopted to fulfill the crack initiation and propagation. The cover-division strategy can avoid the mesh dependency to some extent because of the non-local nature of the stress. Algorithms are implemented to treat the manifold elements, the physical covers and the loops during the fracturing process. The developed program has been applied to simulate the progressive failure of rock slopes with non-persistent joints. Numerical results indicate that it is able to capture the fracturing in intact rock bridge and finally allow the kinematic release. The developed program has also been applied to investigate the potential failure mechanisms of footwall slopes in surface coal mining.
author2 Ma Guowei
author_facet Ma Guowei
An, Xinmei
format Theses and Dissertations
author An, Xinmei
author_sort An, Xinmei
title Extended numerical manifold method for engineering failure analysis
title_short Extended numerical manifold method for engineering failure analysis
title_full Extended numerical manifold method for engineering failure analysis
title_fullStr Extended numerical manifold method for engineering failure analysis
title_full_unstemmed Extended numerical manifold method for engineering failure analysis
title_sort extended numerical manifold method for engineering failure analysis
publishDate 2010
url https://hdl.handle.net/10356/42227
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