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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Applying the Newmark Method to the Discontinuous Deformation Analysis

Peng, Bo 08 December 2014 (has links)
Discontinuous deformation analysis (DDA) is a newly developed simulation method for discontinuous systems. It was designed to simulate systems with arbitrary shaped blocks with high efficiency while providing accurate solutions for energy dissipation. But DDA usually exhibits damping effects that are inconsistent with theoretical solutions. The deep reason for these artificial damping effects has been an open question, and it is hypothesized that these damping effects could result from the time integration scheme. In this thesis two time integration methods are investigated: the forward Euler method and the Newmark method. The work begins by combining the Newmark method and the DDA. An integrated Newmark method is also developed, where velocity and acceleration do not need to be updated. In simulations, two of the most widely used models are adopted to test the forward Euler method and the Newmark method. The first one is a sliding model, in which both the forward Euler method and the Newmark method give accurate solutions compared with analytical results. The second model is an impacting model, in which the Newmark method has much better accuracy than the forward Euler method, and there are minimal damping effects. / Master of Science
2

An Analysis Of Degirmendere Shore Landslide During 17 August 1999 Kocaeli Earthquake

Bulbul, Oguzhan 01 December 2006 (has links) (PDF)
In this study, the failure mechanism of the shore landslide which occured at Degirmendere coast region during 17 August 1999 Kocaeli (Izmit) - Turkey earthquake is analyzed. Geotechnical studies of the region are at hand, which reveal soil properties and geological formation of the region as well as the topography of the shore basin after deformations. The failure is analyzed as a landslide and permanent displacements are calculated by Newmark Method under 17 August 1999 Izmit record, scaled to a maximum acceleration of 0.4g. There are discussions on the main dominating mechanism of failure / landslide, liquefaction, fault rupture and lateral spreading. According to the studies, the failure mechanism is a seismically induced shore landslide also triggered by liquefaction and fault rupture, accompanied by the mechanism of lateral spreading by turbulence. A seismically induced landslide is discussed and modeled in this study. The finite element programs TELSTA and TELDYN are employed for static and dynamic analyses. Slope stability analyses are performed with the program SLOPE. The permanent displacements are calculated with Newmark Method, with the help of a MATLAB program, without considering the excess pore pressures.
3

Analise dinamica linear de porticos planos pelo metodo dos elementos finitos / Linear dynamic analysis of plane framework with use of the finite element method

Gatti, Anderson Carlos 29 June 2006 (has links)
Orientador: Aloisio Ernesto Assan / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-07T10:17:54Z (GMT). No. of bitstreams: 1 Gatti_AndersonCarlos_M.pdf: 1799347 bytes, checksum: c5db751be8130693e5a2966d279bc22e (MD5) Previous issue date: 2006 / Resumo: Neste trabalho estuda-se o comportamento de pórticos planos submetidos a ações dinâmicas. Apresenta-se, inicialmente, a Equação de Movimento de Lagrange através das variações das energias cinética, potencial mais o trabalho das forças não conservativas. Em seguida, pelo emprego do Método dos Elementos Finitos são desenvolvidas as matrizes de rigidez, massa e amortecimento para o elemento de pórtico plano. O amortecimento introduzido é o de Rayleigh. Estudam-se dois métodos para a realização da análise dinâmica: o método de Newmark e o Método da Superposição Modal, também sendo realizado um estudo do problema de autovalor e autovetor pelo emprego do Método das Potências e o Método da Deflação de Wielandt. Os autovalores e autovetores fornecerão as freqüências naturais e os modos de vibração da estrutura. Finalmente, são mostrados exemplos numéricos para a análise do comportamento dos pórticos planos / Abstract: In this work, it is studied the behavior of plane frames submitted to dynamic loads. First of all Lagrange¿s Equations of Motion is presented by the kinetic and potential energy variation plus the work of the nonconservative forces. Next, the stiffness, mass and damping matrices for the plane frame element are developed with the use of the Finite Element Method. Damping is introduced from the Rayleigh damping. Both Newmark Method and Modal Superposition Method are studied to carry out the dynamic analysis. It is also carried out a study of the eigenvalue problem by Power Method and Wielandt Deflation Method. Eigenvalues and eigenvectors will provide the natural frequencies and normal modes of the structure, respectively. Finally, numerical examples are related to the analysis of the plane frameworks behavior / Mestrado / Estruturas / Mestre em Engenharia Civil

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