NAZIM NARIMAN (6 Ergebnisse)

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Taschenbuch. Zustand: Neu. Druck auf Anfrage Neuware - Printed after ordering - Research Paper (postgraduate) from the year 2014 in the subject Engineering - Civil Engineering, grade: unknown, University of Weimar, language: English, abstract: The vibration characteristic of a cable stayed bridges structure is the main axis of the study in this paper, many structural parameters are used to simulate and determine the effect of vibration on the structural performance by identifying the natural frequencies of the system and the mode shapes that can occur in the real structure. Modeling the stay cables with three famous styles of arrangements such as Harp, Semi Harp and Fan styles, and assigning roller, hinged and fixed boundary conditions on the deck support of the cable stayed bridge, in addition to using two design cases of the girders and pylons dimensions in the global structure for that purpose. Through the use of ABAQUS finite element analysis, the models were generated for each mentioned cases and the results of the frequency linear perturbation step of 10 mode shapes were determined through the simulation of the deformed shapes and the determined values of the natural frequencies of each mode for each case of interest. It was seen that the roller boundary condition was much prone to the early vibration and the stay cables of the direction near to the roller support were vibrated and stressed much more than the other direction compared with the hinged and fixed boundary conditions, and the mode shapes 7, 8, 9 and 10 were the most vibrated cases for all the boundary conditions without any distinction. The week design of the girders and the pylons has the great effect on the vibration of the stay cables, pylons and deck of the structure especially near the roller support direction due to the early vibration of the case of roller support, so the use of cross ties and damping between the stay cables and the girders are very important in the cases of significant vibrations which affect the performance of the cable stayed bridges.

Taschenbuch. Zustand: Neu. Druck auf Anfrage Neuware - Printed after ordering - Research Paper (postgraduate) from the year 2013 in the subject Physics - Mechanics, grade: 3.70, University of Weimar, language: English, abstract: In this paper, two types of steel frames, steel frame without side sway permission and another with side sway permission are created in Abaqus with 10 multiple slenderness ratio of the columns by changing the length every time starting from 1 M and ending with 10 M length of the columns, Twenty models of steel frames with single story and single bay were created, the models are with the same 2D dimensions and material properties, the cross section of the steel is (0.5\*0.5) M ,and the supports are fixed, two equal forces P= 1000 N are exerted on the frames in the position mentioned in fig 6, a beam section was defined for the frame integrated before analysis with Young modulus of elasticity E=1\*107 N/M2 , and shear modulus G = 3.8\*106 N/M2 and poisons ratio ni = 0.3.A linear perturbation step is created for buckling and 10 eigenvalues are requested for analysis, a standard quadratic beam element type is generated with global seeding of 0.6, and 20 Jobs are created for every situation and conclusions have been obtained, the critical buckling loads of the frames fall in the ranges between the Euler loads forms which has been proved for each type of frames and this scientific approach was verified in this research, in addition to that the relation between the length of the column and the eigenvalues that represent the critical loads of buckling verified, and the simulations of the mode shapes of buckling of the steel frames were identified adopting finite element analysis which shows the amount of loads necessary to reach each mode shape of buckling for each type of steel frames mentioned before.

Taschenbuch. Zustand: Neu. Druck auf Anfrage Neuware - Printed after ordering - Scientific Study from the year 2013 in the subject Engineering - Civil Engineering, grade: -, University of Weimar, course: Cable Stayed Bridges, language: English, abstract: In this research, many models of a cable stayed bridge were generated using ABAQUS finite element commercial software for the purpose of proceeding with nonlinear design optimization on the shape and topology of the structure. The cable stayed bridge models in all cases are with a constant length and width for the deck, also the pylons height under and above the deck is constant, but the shape of stay cables arrangement varies to three main famous arrangements which are Fan, Semi harp and Harp.In addition to change in the pylons shape which are three known shapes Double out, Single Center and Single inclined out, and it is worthy to mention that in all cases of the shape optimization of the pylons , the stay cables arrangements are Fan style, andby governing computational nonlinear optimization process on the finite element models in all cases of shape and topology optimization through using static general step for analysis and a certain meshing type with global seeding size for the Beam elements, with a fixed and pinned boundary conditions for the deck supports and fixed boundary for the pylons.Concentrated static loads assigned on the same positions on the deck for all models cases.A numerical optimization and graphical simulation of the results were used to determine many responsesin the model cases which areReactions, Deflections and Mises stresses in the structural models of the cable stayed bridge, especially at the deck, pylons and the stay cables which are the main components of the structure, also the same step in the deck and pylons supportshas been done for optimization outputs.It is apparent and clear that the cable stayed model with the Fan arrangement of the stay cables showed efficiency and the best topological model case for the structural design optimization that involved a safe, robust, rigid, and safe for the design of cable stayed bridges.The pylon shape with double out case was the best design situation compared with the other two models single center and single inclined out shapes, this point was obvious in the reactions, deflections and Mises stresses for the deck supports and the deck itself, and as a result the Double out with a Fan shape arrangement of the cable stays is the best model for the design of cable stayed bridges to resist the static loads.

Taschenbuch. Zustand: Neu. Twisted High Rise Steel Structures In Diagrid System | Modeling,Design,Analysis and Recommendations | Nazim Abdul Nariman | Taschenbuch | 192 S. | Englisch | 2010 | LAP LAMBERT Academic Publishing | EAN 9783843381369 | Verantwortliche Person für die EU: BoD - Books on Demand, In de Tarpen 42, 22848 Norderstedt, info[at]bod[dot]de | Anbieter: preigu.

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