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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.
271

Variational asymptotic modeling of composite dimensionally reducible structures

Yu, Wenbin 05 1900 (has links)
No description available.
272

Bio-membranes : a bio-logical approach to architecture / Biological approach to architecture

Karapa, Eleni January 1996 (has links)
Bio-membranes: A Biological Approach to Architecture The desire to introduce an area of study which can potentially inform the field of architecture on a theoretical as well as on a practical level, is the primary aim of this creative project. More specifically, the interest of this work is focused on the identification of useful processes deriving from the world of biology and their utilization in the world of architecture. The designation of an alternative path for perceiving and understanding processing and principles that may be of use in the reconfiguration of various architectural design applications is in quest. In search of a biological model that can potentially inform the field of architecture and provide enough feedback concerning the understanding of "processing" and "principles", biomembrane systems have been designated as the appropriate subject of study. The study and analysis of the structural and functional aspects of the bio-membranes as well as the extraction of useful principles that are derived from this study consist the first part of this work. The second part describes the implementation of these principles into various architectural applications while it challenges existing paradigms and introduces new ways of looking into the realm of architectural theory. / Department of Architecture
273

Optimal integrated multi-sensor system for full-scale structural monitoring based on advanced signal processing

Li, Xiaojing, School of Electrical Engineering & Telecommunications & School of Surveying & Spatial Information Systems, UNSW January 2006 (has links)
Modern civil structures as well as loads on them are still too complex to be accurately modeled or simulated. Therefore, structural failures and structural defects are NOT uncommon! More and more full-scale structural monitoring systems have been deployed in order to monitor how structures behave under various loading conditions. This research focuses on how to maximise benefits from such full-scale measurements by employing advanced digital signal processing techniques. This study is based on accelerometer and GPS data collected on three very different structures, namely, the steel tower in Tokyo, the long and slender suspension bridge in Hong Kong, and the tall office tower in Sydney, under a range of loading conditions, i.e., typhoon, earthquake, heavy traffic, and small scale wind. Systematic analysis of accelerometer and GPS data has demonstrated that the two sensors complement each other in monitoring the static, quasi-static and dynamic movements of the structures. It has also been confirmed that the Finite Element Model could under-estimate the natural frequencies of structures by more than 40% in some case. The effectiveness of using wavelet to de-noise GPS measurement has been demonstrated. The weakness and strengths of accelerometer and GPS have been identified and framework has been developed on how to integrate the two as well as how to optimize the integration. The three-dimensional spectral analysis framework has been developed which can track the temporal evolution of all the frequency components and effectively represents the result in the 3D spectrogram of frequency, time and magnitude. The dominant frequency can also be tracked on the 3D mesh to vividly illustrate the damping signature of the structure. The frequency domain coherent analysis based on this 3D analysis framework can further enhance the detection of common signals between sensors. The developed framework can significantly improve the visualized performance of the integrated system without increasing hardware costs. Indoor experiments have shown the excellent characteristics of the optical fibre Bragg gratings (FBGs) for deformation monitoring. Innovative and low-cost approach has been developed to measure the shift of FBG???s central wavelength. Furthermore, a schematic design has been completed to multiplex FBGs in order to enable distributed monitoring. In collaboration with the University of Sydney, the first Australian full-scale structural monitoring system of GPS and accelerometer has been deployed on the Latitude Tower in Sydney to support current and future research.
274

The behaviour and design of thin walled concrete filled steel box columns

Mursi, Mohanad, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2007 (has links)
This thesis investigates the behaviour of hollow and concrete filled steel columns fabricated from thin steel plates. The columns are investigated under axial, uniaxial and biaxial loading. The currently available international standards for composite structures are limited to the design of concrete filled steel columns with compact sections and yield stress of steel up to 460 N/mm2. This thesis consists of both experimental and analytical studies and design recommendations for future use. Three comprehensive series of experimental tests are conducted on hollow and concrete filled steel columns. The principal parameters that have been considered in the test programmes are the slenderness of the component plates, the yield stress of the steel and the loading conditions. In the first test series, three slender hollow steel columns and three slender composite columns are tested under uniaxial loading. The steel utilised is mild steel. High strength steel is utilised in the second test programme. In this test series four stub columns, eight short columns and eight slender columns are tested, each set consists of four hollow and four composite columns. Short columns are tested under axial loading to investigate the confinement effect provided by the steel casing. Slender columns are tested under uniaxial loading to investigate the coupled instability of local and global buckling. The third test programme is quite novel and considers the behaviour of hollow and concrete filled steel columns fabricated with high strength structural steel plate and subjected to biaxial bending. In this test eight short columns and ten slender columns each of them consisting of hollow and composite columns are investigated under biaxial loading. Analytical models are developed herein to elucidate the behaviour of the hollow and composite columns considering cross section slenderness, yield stress and loading conditions. An iterative model considering the coupled global and local buckling in the elastic and plastic range incorporating material nonlinearities is developed to investigate the behaviour of slender columns fabricated from mild steel. An improved deformation control model is developed to investigate the behaviour of slender high strength steel columns considering the confinement effect and local and post-local buckling in the elastic and plastic range. Then a numerical model for biaxial bending is developed to study the behaviour of short and slender concrete filled high strength steel columns under biaxial loading incorporating interaction buckling considering material and geometric nonlinearities. The scope of the thesis presents a wide range of experimental and theoretical studies of an extremely novel nature. It demonstrates the benefit of confinement and the consideration of local and post-local buckling in the elastic and plastic range. It is hoped that this research will contribute to the area of composite steel-concrete structural applications.
275

Design and structural modifications of vibratory systems to achieve prescribed modal spectra / Dmitri D. Sivan.

Sivan, D. D. January 1997 (has links)
Bibliography: leaves 184-192. / xii, 198 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis reports on problems associated with design and structural modification of vibratory systems. Several common problems encountered in practical engineering applications are described and novel strategies for solving this problems are proposed. Mathematical formulations of these problems are generated, and solution methods are developed. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1997
276

Measurement selection and parameter estimation strategies for structural stiffness and mass updating using non-destructive test data /

Javdekar, Chitra N. January 2004 (has links)
Thesis (Ph.D.)--Tufts University, 2004. / Adviser: Masoud Sanayei. Submitted to the Dept. of Civil Engineering. Includes bibliographical references (leaves 300-305). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
277

A new development in domain decomposition techniques for analysis of plates with mixed edge supports /

Su, Guo Hua. January 2000 (has links)
Thesis (M.Sc. (Hons))--University of Western Sydney, Nepean, 2000. / "A thesis submitted by Guo Hua Su for the degree of Master of Engineering (Honours), School of Civic Engineering and Environment, University of Western Sydney, Nepean Campus, August, 2000." Includes appendices. Bibliography : leaves 9-1 to 9-12.
278

Development of a finite element based nominal stress extraction procedure for fatigue analysis of welded structures

Grove, Alewyn Petrus. January 2006 (has links)
Thesis (M.Eng.(Mechanical and Aeronautical Engineering))-University of Pretoria, 2006. / Abstract in English and Afrikaans. Includes bibliographical references.
279

Analysis of the AASHTO fatigue design provisions for welded steel bridge details using reliability theory

Cross, Benjamin Thomas. January 2007 (has links)
Thesis (M.C.E.)--University of Delaware, 2007. / Includes bibliographical references (p. 87-90).
280

A state estimation framework for ultrasonic structural health monitoring of fastener hole fatigue cracks

Cobb, Adam. January 2008 (has links)
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Michaels, Jennifer; Committee Member: Habetler, Thomas; Committee Member: Jacobs, Laurence; Committee Member: Michaels, Thomas; Committee Member: Vachtsevanos, George.

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